Commitments And Contingencies

12 Months Ended

Dec. 31, 2011

Commitments And Contingencies

NOTE 15 – COMMITMENTS AND CONTINGENCIES

We are involved in legal, tax and regulatory proceedings before various courts, regulatory commissions, and governmental agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in these notes to our financial statements, will not have a material adverse effect on our results of operations, financial position, or liquidity.

See also Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 10 – Callaway Energy Center and Note 14 – Related Party Transactions in this report.

Callaway Energy Center

The following table presents insurance coverage at Ameren Missouri's Callaway energy center at December 31, 2011. The property coverage and the nuclear liability coverage must be renewed on April 1 and January 1, respectively, of each year.

Type and Source of Coverage	Maximum Coverages			Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers	$	375			$        -
Pool participation		12,219	(a)		118	(b)
	$	12,594	(c)		$   118
Property damage:
Nuclear Electric Insurance Ltd.	$	2,750	(d)		$     23
Replacement power:
Nuclear Electric Insurance Ltd	$	490	(e)		$       9
Energy Risk Assurance Company	$	64	(f)		$        -

(a) Provided through mandatory participation in an industrywide retrospective premium assessment program.

(b) Retrospective premium under Price-Anderson. This is subject to retrospective assessment with respect to a covered loss in excess of $375 million in the event of an incident at any licensed U.S. commercial reactor, payable at $17.5 million per year.

(c) Limit of liability for each incident under the Price-Anderson liability provisions of the Atomic Energy Act of 1954, as amended. A company could be assessed up to $118 million per incident for each licensed reactor it operates with a maximum of $17.5 million per incident to be paid in a calendar year for each reactor. This limit is subject to change to account for the effects of inflation and changes in the number of licensed reactors.

(d) Provides for $500 million in property damage and decontamination, excess property insurance, and premature decommissioning coverage up to $2.25 billion for losses in excess of the $500 million primary coverage.

(e) Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. Weekly indemnity up to $4.5 million for 52 weeks, which commences after the first eight weeks of an outage, plus up to $3.6 million per week for a minimum of 71 weeks thereafter for a total not exceeding the policy limit of $490 million.

(f) Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. The coverage commences after the first 52 weeks of insurance coverage from Nuclear Electric Insurance Ltd. and is for a weekly indemnity of $900,000 for 71 weeks in excess of the $3.6 million per week set forth above. Energy Risk Assurance Company is an affiliate and has reinsured this coverage with third-party insurance companies. See Note 14 – Related Party Transactions for more information on this affiliate transaction.

The Price-Anderson Act is a federal law that limits the liability for claims from an incident involving any licensed United States commercial nuclear power facility. The limit is based on the number of licensed reactors. The limit of liability and the maximum potential annual payments are adjusted at least every five years for inflation to reflect changes in the Consumer Price Index. The five-year inflationary adjustment as prescribed by the most recent Price-Anderson Act renewal was effective October 29, 2008. Owners of a nuclear reactor cover this exposure through a combination of private insurance and mandatory participation in a financial protection pool, as established by Price-Anderson.

Losses resulting from terrorist attacks are covered under Nuclear Electric Insurance Ltd.'s policies, subject to an industrywide aggregate policy limit of $3.24 billion within a 12-month period for coverage for such terrorist acts.

If losses from a nuclear incident at the Callaway energy center exceed the limits of, or are not covered by, insurance, or if coverage is unavailable, Ameren Missouri is at risk for any uninsured losses. If a serious nuclear incident were to occur, it could have a material adverse effect on Ameren's and Ameren Missouri's results of operations, financial position, or liquidity.

Leases

We lease various facilities, office equipment, plant equipment, and rail cars under operating leases. The following table presents our lease obligations at December 31, 2011:

	Total		2012		2013		2014		2015		2016		After 5 Years
Ameren:(a)
Capital lease payments(b)	$	621	$	33	$	32	$	32	$	33	$	33	$	458
Less amount representing interest		312		28		27		27		27		27		176
Present value of minimum capital lease payments	$	309	$	5	$	5	$	5	$	6	$	6	$	282
Operating leases(c)		307		38		32		26		26		25		160
Total lease obligations	$	616	$	43	$	37	$	31	$	32	$	31	$	442
Ameren Missouri:
Capital lease payments(b)	$	621	$	33	$	32	$	32	$	33	$	33	$	458
Less amount representing interest		312		28		27		27		27		27		176
Present value of minimum capital lease payments	$	309	$	5	$	5	$	5	$	6	$	6	$	282
Operating leases(c)		134		13		12		12		12		12		73
Total lease obligations	$	443	$	18	$	17	$	17	$	18	$	18	$	355
Ameren Illinois:
Operating leases(c)	$	7	$	1	$	1	$	1	$	1	$	1	$	2
Genco:
Operating leases(c)	$	131	$	11	$	11	$	11	$	10	$	11	$	77

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

(b) See Properties under Part I, Item 2, and Note 3 – Property and Plant, Net of this report for additional information.

(c) Amounts related to certain real estate leases and railroad licenses have indefinite payment periods. Ameren's $2 million annual obligation for these items is included in the 2012 through 2016 columns. The amounts for the indefinite payments are not included in the After 5 Years column because that period is indefinite.

The following table presents total rental expense, included in operating expenses, for the years ended December 31, 2011, 2010 and 2009:

	2011		2010		2009
Ameren(a)	$	47	$	52	$	50
Ameren Missouri		29		29		30
Ameren Illinois		17		19		19
Genco		12		13		15

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

Other Obligations

To supply a portion of the fuel requirements of our generating plants, we have entered into various long-term commitments for the procurement of coal, natural gas, nuclear fuel, and methane gas. We also have entered into various long-term commitments for purchased power and natural gas for distribution. The table below presents our estimated fuel, purchased power, and other commitments at December 31, 2011. Ameren's and Ameren Missouri's coal commitments include multiyear agreements to procure ultra-low-sulfur coal and related transportation from the Powder River Basin in Wyoming. Ameren's and Ameren Missouri's purchased power obligations include a 102-MW power purchase agreement with a wind farm operator that expires in 2024. Ameren's and Ameren Illinois' purchased power obligations include the Ameren Illinois power purchase agreements entered into as part of the IPA-administered power procurement process. Included in the Other column are minimum purchase commitments under contracts for equipment, design and construction, meter reading services, and an Ameren tax credit obligation at December 31, 2011. Ameren's tax credit obligation is a $17 million note payable issued for an investment in a commercial real estate development partnership to acquire tax credits. This note payable was netted against the related investment in "Other assets" on Ameren's balance sheet at December 31, 2011, as Ameren has a legally enforceable right to offset under authoritative accounting guidance.

	Coal		Natural Gas		Nuclear Fuel		Purchased Power		Methane Gas		Other		Total
Ameren:(a)
2012	$	1,120	$	398	$	36	$	196	$	1	$	221	$	1,972
2013		792		295		37		309		3		80		1,516
2014		692		220		96		125		3		75		1,211
2015		687		116		90		51		3		52		999
2016		674		39		100		52		3		62		930
Thereafter		968		134		298		746		94		246		2,486
Total	$	4,933	$	1,202	$	657	$	1,479	$	107	$	736	$	9,114
Ameren Missouri:
2012	$	623	$	63	$	36	$	19	$	1	$	78	$	820
2013		605		48		37		19		3		50		762
2014		625		36		96		19		3		47		826
2015		614		19		90		19		3		28		773
2016		644		7		100		19		3		38		811
Thereafter		921		30		298		155		94		144		1,642
Total	$	4,032	$	203	$	657	$	250	$	107	$	385	$	5,634
Ameren Illinois:
2012	$	-	$	324	$	-	$	177	$	-	$	24	$	525
2013		-		243		-		290		-		22		555
2014		-		180		-		106		-		22		308
2015		-		94		-		32		-		24		150
2016		-		31		-		33		-		24		88
Thereafter		-		105		-		591		-		102		798
Total	$	-	$	977	$	-	$	1,229	$	-	$	218	$	2,424
Genco:
2012	$	355	$	9	$	-	$	-	$	-	$	98	$	462
2013		108		4		-		-		-		5		117
2014		40		3		-		-		-		5		48
2015		45		2		-		-		-		-		47
2016		-		-		-		-		-		-		-
Thereafter		-		-		-		-		-		-		-
Total	$	548	$	18	$	-	$	-	$	-	$	108	$	674

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

Also, as part of the 2007 Illinois Electric Settlement Agreement, Ameren Illinois entered into financial contracts with Marketing Company to lock in energy prices for 400 to 1,000 megawatts annually of their round-the-clock power requirements from 2008 to 2012. These commitments are not reflected in the above table. See Note 7 – Derivative Financial Instruments and Note 14 – Related Party Transactions for additional information.

In February 2012, a rate stability procurement for energy products and renewable energy credits was administered by the IPA for the June 2013 through May 2017 period to meet certain requirements for purchased power related to the IEIMA. Ameren Illinois contracted to purchase approximately 13 million megawatthours of energy products at an average price of approximately $31 per megawatthour. Ameren Illinois is currently reviewing the results of the renewable energy credits procurement proceeding.

Ameren Illinois has entered into an agreement to purchase approximately 15.5 billion cubic feet of synthetic natural gas annually over a 10-year period beginning in 2016 for its natural gas customers. The agreement is contingent on the counterparty reaching certain milestones during the project development and the construction of the plant that will produce the synthetic natural gas. Construction has not begun on the plant; therefore, Ameren Illinois' obligations are not yet certain at this time. The agreement was entered into pursuant to an Illinois law which became effective August 2, 2011, and provides that all contract costs for synthetic natural gas incurred by Ameren Illinois are reasonable and prudent and recoverable through the PGA and are not subject to review or disallowance by the ICC.

Environmental Matters

We are subject to various environmental laws and regulations enforced by federal, state, and local authorities. From the beginning phases of siting and development to the ongoing operation of existing or new electric generating, transmission and distribution facilities, natural gas storage, transmission and distribution facilities, our activities involve compliance with diverse environmental laws and regulations. These laws and regulations address emissions, impacts to air, land and water, noise, protected natural and cultural resources (such as wetlands, endangered species and other protected wildlife, and archeological and historical resources), and chemical and waste handling. Complex and lengthy processes are required to obtain approvals, permits, or licenses for new, existing or modified facilities. Additionally, the use and handling of various chemicals or hazardous materials (including wastes) requires release prevention plans and emergency response procedures.

In addition to existing laws and regulations, including the Illinois MPS that applies to our energy centers in Illinois, the EPA is developing numerous new environmental regulations that will have a significant impact on the electric utility industry. These regulations could be particularly burdensome for certain companies, including Ameren, Ameren Missouri and Genco, that operate coal-fired energy centers. Significant new rules proposed or promulgated since the beginning of 2010 include the regulation of greenhouse gas emissions; revised national ambient air quality standards for SO₂ and NO₂ emissions; the CSAPR, which requires further reductions of SO₂ and NO_x emissions from power plants; a regulation governing management of CCR and coal ash impoundments; the MATS, which requires reduction of emissions of mercury, toxic metals, and acid gases from power plants; revised NSPS for particulate matter, SO₂, and NO_x emissions from new sources; and new regulations under the Clean Water Act that could require significant capital expenditures such as new water intake structures or cooling towers at our energy centers. The EPA also plans to propose an additional rule, applicable to new and existing electric generating units, governing NSPS and emission guidelines for greenhouse gas emissions. These new regulations may be litigated, so the timing of their implementation is uncertain, as evidenced by the stay of the CSAPR by the United States Court of Appeals for the District of Columbia on December 30, 2011. Although many details of these future regulations are unknown, the combined effects of the new and proposed environmental regulations may result in significant capital expenditures and/or increased operating costs over the next five to ten years for Ameren, Ameren Missouri and Genco. Actions required to ensure that our facilities and operations are in compliance with environmental laws and regulations could be prohibitively expensive. If they are, these regulations could require us to close or to significantly alter the operation of our energy centers, which could have an adverse effect on our results of operations, financial position, and liquidity, including the impairment of plant assets. Failure to comply with environmental laws and regulations might also result in the imposition of fines, penalties, and injunctive measures.

The estimates in the table below contain all of the known capital costs to comply with existing environmental regulations and our assessment of the potential impacts of the EPA's proposed regulation for CCR, the recently finalized MATS, the stayed CSAPR as currently designed, and the revised national ambient air quality standards for SO₂ and NO_x emissions as of December 31, 2011. The estimates in the table below assume that CCR will continue to be regarded as nonhazardous. The estimates in the table below do not include the impacts of new regulations proposed by the EPA under the Clean Water Act in March 2011 regarding cooling water intake structures as our evaluation of those impacts is ongoing. The estimates shown in the table below could change significantly depending upon a variety of factors including:

Ÿ additional federal or state requirements;

Ÿ regulation of greenhouse gas emissions;

Ÿ new national ambient air quality standards or changes to existing standards for ozone, fine particulates, SO₂, and NO_x emissions;

Ÿ additional rules governing air pollutant transport;

Ÿ finalized regulations under the Clean Water Act;

Ÿ CCR being classified as hazardous;

Ÿ whether the CSAPR is implemented and whether any modifications are made to its existing requirements;

Ÿ new technology;

Ÿ expected power prices;

Ÿ variations in costs of material or labor; and

Ÿ alternative compliance strategies or investment decisions.

	2012		2013 - 2016				2017 - 2021				Total
AMO(a)	$	55	$	325 -	$	400	$	845 -	$	1,030	$	1,225 -	$	1,485
Genco		150		100 -		125		245 -		295		495 -		570
AERG		5		20 -		25		80 -		100		105 -		130
Ameren	$	210	$	445 -	$	550	$	1,170 -	$	1,425	$	1,825 -	$	2,185

(a) Ameren Missouri's expenditures are expected to be recoverable from ratepayers.

The decision to make pollution control equipment investments at our Merchant Generation business depends on whether the expected future market price for power reflects the increased cost for environmental compliance. In early 2012, there has been a decline in the market price for wholesale power because of factors such as declining natural gas prices and the stay of the CSAPR. As a result of this decline in the market price for power, as well as uncertain environmental regulations, Genco is decelerating the construction of two scrubbers at of its Newton energy center. These scrubbers were originally expected to be installed in late 2013 and spring 2014. The ultimate installation of these scrubbers, now estimated to occur between 2017 and 2021 in the table above, has been postponed until such time as the incremental investment necessary for completion is justified by visible market conditions. However, Genco will continue to incur capital costs related to the construction of these scrubbers. The table above includes Genco's estimated costs of approximately $150 million in 2012 and approximately $20 million annually, excluding capitalized interest, from 2013 through 2016 for the construction of the two scrubbers. In addition to Genco's reduction in estimated capital expenditures, AERG is deferring precipitator upgrades at its E.D. Edwards energy center beyond 2016.

The following sections describe the more significant environmental rules that affect our operations.

Clean Air Act

Both federal and state laws require significant reductions in SO₂ and NO_x emissions that result from burning fossil fuels. In March 2005, the EPA issued regulations with respect to SO₂ and NO_x emissions (the CAIR). The CAIR required generating facilities in 28 states, including Missouri and Illinois, and the District of Columbia to participate in cap-and-trade programs to reduce annual SO₂ emissions, annual NO_x emissions, and ozone season NO_x emissions.

In December 2008, the United States Court of Appeals for the District of Columbia remanded the CAIR to the EPA for further action to remedy the rule's flaws, but allowed the CAIR's cap-and-trade programs to remain effective until they are replaced by the EPA. In July 2011, the EPA issued the CSAPR as the CAIR replacement. The CSAPR was to become effective on January 1, 2012, for SO₂ and annual NO_x reductions and on May 1, 2012, for ozone season NO_x reductions. In the CSAPR, the EPA developed federal implementation plans for each state covered by this rule; however, each impacted state can develop its own implementation rule starting as early as 2013. The CSAPR establishes emission allowance budgets for each of the states subject to the regulation, including Missouri and Illinois. With the CSAPR, the EPA abandoned CAIR's regional approach to cutting emissions and instead set a pollution budget for each of the impacted states based on the EPA's analysis of each upwind state's contribution to air quality in downwind states. For Missouri and Illinois, emission reductions were required in two phases beginning in 2012, with further reductions in 2014. With the CSAPR, the EPA adopted a cap-and-trade approach that allows intrastate and limited interstate trading of emission allowances with other sources within the same program, that is, in the SO₂ program, in the annual NO_x, or in ozone season NO_x program. Multiple legal challenges were filed requesting to have CSAPR partially or entirely vacated and to stay the implementation of the CSAPR while the court considers the challenges. On December 30, 2011, the United States Court of Appeals for the District of Columbia issued a stay of the CSAPR. The stay does not invalidate the rule, but only delays its implementation until a final court ruling is issued. The United States Court of Appeals for the District of Columbia has expedited its consideration of the regulation and will hear arguments on the validity of CSAPR in April 2012. The ultimate outcome of the challenges to the regulation is uncertain. The court could uphold CSAPR or remand it back to the EPA for partial or entire revision. Until the CSAPR appeal process is concluded, the EPA will continue to administer the CAIR.

On December 21, 2011, the EPA issued the final MATS under the Clean Air Act, which require emission reductions for mercury and other hazardous air pollutants, such as acid gases, toxic metals, and particulate matter by setting emission limits equal to the average emissions of the best performing 12% of existing coal and oil-fired electric generating units. Also, the rule requires reductions in hydrogen chloride emissions, which were not regulated previously, and it may require continuous monitoring systems that are not currently in place. The MATS do not require a specific control technology to achieve the emission reductions. The MATS will apply to each unit at a coal-fired power plant; however, emission compliance can be averaged for the entire power plant. Compliance is required by April 2015 or, with a case-by-case extension, by April 2016.

Separately, in January and June 2010, the EPA finalized new ambient air quality standards for SO₂ and NO₂. It also announced plans for further reductions in the annual national ambient air quality standards for ozone and fine particulates. The state of Illinois and the state of Missouri will be required to develop separate attainment plans to comply with the new ambient air quality standards. Ameren, Ameren Missouri and Genco continue to assess the impacts of these new standards. In September 2011, the EPA withdrew its draft annual national ambient air quality standard for ozone and announced that it was implementing the 2008 national ambient air quality standard for ozone. The EPA is required to revisit this standard again in 2013.

Ameren Missouri's current environmental compliance plan for air emissions from its energy centers includes burning ultra-low-sulfur coal and installing new or optimizing existing pollution control equipment. In July 2011, Ameren Missouri contracted to procure significantly higher volumes of lower-sulfur-content coal than Ameren Missouri's energy centers have historically burned, which will allow Ameren Missouri to eliminate or postpone capital expenditures for pollution control equipment while still achieving required emissions levels. In 2010, Ameren Missouri completed the installation of two scrubbers at its Sioux energy center to reduce SO₂ emissions. Currently, Ameren Missouri's compliance plan assumes the installation of two scrubbers within its coal-fired fleet during the next 10 years and precipitator upgrades at multiple energy centers. However, Ameren Missouri is currently evaluating its operations and options to determine how to comply with the additional emission reductions requirements in 2014 set forth in the CSAPR, if ultimately enacted, the MATS, and other recently finalized or proposed EPA regulations.

Existing Illinois state regulations already required Ameren and Genco to reduce their emissions of mercury under the MPS. Ameren's and Genco's review of the MATS indicates that the scope of the federal standards is broader than the MPS, as no exemption exists for smaller coal-fired plants. Additionally, the MATS are more stringent than the MPS because compliance with the MATS is measured on a quarterly basis and, in some cases, a thirty-day rolling basis and not annually, as allowed under state requirements. At the end of 2011, Genco ceased operations of its Meredosia and Hutsonville energy centers. The closure of these energy centers was primarily due to the expected cost of complying with CSAPR and MATS. See Note 17 – Goodwill, Impairment and Other Charges for additional information.

Genco and AERG expect to install additional, or optimize existing, pollution control equipment, or modify operations to meet new and incremental emission reduction requirements under the MPS, the MATS, or the CSAPR as they become effective. Under the MPS, as amended, Illinois generators are required to reduce mercury, SO₂, and NO_x emissions by 2015. To comply with the MPS and other air emissions laws and regulations, Genco and AERG are installing equipment designed to reduce their emissions of mercury, NO_x, and SO₂. Genco and AERG have installed a total of three scrubbers at two energy centers. Two additional scrubbers are being constructed at Genco's Newton energy center. As discussed above, the timing of the installation of these scrubbers as well as precipitator upgrades at AERG's E.D. Edwards energy center have been extended. The closure of Genco's Meredosia and Hutsonville energy centers will allow the Merchant Generation segment additional flexibility in the methods to achieve compliance with environmental standards. Merchant Generation and Genco will continue to review and adjust their compliance plans in light of evolving outlooks for power and capacity prices, delivered fuel costs, environment standards and compliance technologies, among other factors.

The completion of Ameren's, Ameren Missouri's and Genco's review of recently finalized environmental regulations and compliance measures could result in significant increases in capital expenditures and operating costs. The compliance costs could be prohibitive at some of our energy centers as the expected return from these investments, at current market prices for energy and capacity, might not justify the required capital expenditures or their continued operation, which could result in the impairment of long-lived assets.

Emission Allowances

The Clean Air Act created marketable commodities called allowances under the acid rain program, the NO_x budget trading program, the CAIR, and the CSAPR. With the CSAPR, the EPA adopted a cap-and-trade approach that allows intrastate and limited interstate trading of emission allowances with other sources within the same program, that is, either the SO₂, annual NO_x, or ozone season NO_x programs. As noted above, on December 30, 2011, the United States Court of Appeals for the District of Columbia issued a stay of the CSAPR. Until the CSAPR appeal process is concluded, the EPA will continue to administer the CAIR including its allowance program. See Note 1 – Summary of Significant Accounting Policies for the SO₂ and NO_x emission allowance book values that were classified as intangible assets as of December 31, 2011 and 2010, and Note 17 – Goodwill, Impairment and Other Charges for information regarding the emission allowance impairments recorded during 2011 and 2010.

Environmental regulations including the CAIR and the CSAPR, the timing of the installation of pollution control equipment, fuel mix, and the level of operations, will have a significant impact on the number of allowances required for ongoing operations. The CAIR uses the acid rain program's allowances for SO₂ emissions and created annual and ozone season NO_x allowances. The CSAPR, however, will not rely upon the acid rain program, the NO_x budget trading program, or CAIR allowances for its allowance allocation program. Instead, the EPA issued a new type of emissions allowance for each program under the CSAPR. Any unused SO₂ allowances, annual NO_x allowances, and ozone season NO_x allowances issued under CAIR cannot be used for compliance with CSAPR. Ameren, Ameren Missouri and Genco expect to have adequate CAIR allowances for 2012 to avoid needing to make external purchases.

Should the CSAPR become effective as issued, Ameren, Ameren Missouri and Genco are studying their compliance options to identify additional opportunities that may exist for compliance in an economical fashion. Ameren, Ameren Missouri and Genco may be required to purchase emission allowances, if available, to install new or optimize existing pollution control equipment, to limit generation, or take other actions to achieve compliance with the CSAPR in future phase-in years.

Global Climate Change

State and federal authorities, including the United States Congress, have considered initiatives to limit greenhouse gas emissions and to address global climate change. Potential impacts from any climate change legislation or regulation could vary, depending upon proposed CO₂ emission limits, the timing of implementation of those limits, the method of distributing any allowances, the degree to which offsets are allowed and available, and provisions for cost-containment measures, such as a "safety valve" provision that provides a maximum price for emission allowances. As a result of our diverse fuel portfolio, our emissions of greenhouse gases vary among our energy centers, but coal-fired power plants are significant sources of CO₂. The enactment of a climate change law could result in a significant rise in household costs and rates for electricity could rise significantly. The burden could fall particularly hard on electricity consumers and upon the economy in the Midwest because of the region's reliance on electricity generated by coal-fired power plants. Natural gas emits about half as much CO₂ as coal when burned to produce electricity. Therefore, climate change regulation could cause the conversion of coal-fired power plants to natural gas, or the construction of new natural gas plants to replace coal-fired power plants. As a result, economywide shifts to natural gas as a fuel source for electricity generation also could affect the cost of heating for our utility customers and many industrial processes that use natural gas.

In December 2009, the EPA issued its "endangerment finding" under the Clean Air Act which stated that greenhouse gas emissions, including CO₂, endanger human health and welfare and that emissions of greenhouse gases from motor vehicles contribute to that endangerment. In March 2010, the EPA issued a determination that greenhouse gas emissions from stationary sources, such as power plants, would be subject to regulation under the Clean Air Act effective the beginning of 2011. As a result of these actions, we are required to consider the emissions of greenhouse gases in any air permit application.

Recognizing the difficulties presented by regulating at once virtually all emitters of greenhouse gases, the EPA finalized in May 2010 regulations, known as the "Tailoring Rule," that established new higher thresholds for regulating greenhouse gas emissions from stationary sources, such as power plants. The Tailoring Rule became effective in January 2011. The rule requires any source that already has an operating permit to have greenhouse-gas-specific provisions added to its permits upon renewal. Currently, all Ameren energy centers have operating permits that, when renewed, may be modified to address greenhouse gas emissions. The Tailoring Rule also provides that if projects performed at major sources result in an increase in emissions of greenhouse gases of at least 75,000 tons per year, measured in CO₂ equivalents, such projects could trigger permitting requirements under the NSR programs and the application of best available control technology, if any, to control greenhouse gas emissions. New major sources are also required to obtain such a permit and to install the best available control technology if their greenhouse gas emissions exceed the applicable emissions threshold. Separately, in December 2010, the EPA announced a settlement agreement under which it would propose NSPS for greenhouse gas emissions at new and existing fossil fuel-fired power plants by July 26, 2011 and issue a final standard by May 2012. The EPA has not yet proposed a rule and has not specified a new estimate of when it will issue that standard. It is uncertain whether reductions to greenhouse gas emissions would be required at Ameren's, Ameren Missouri's or Genco's energy centers as a result of any of the EPA's new and future rules. Legal challenges to the EPA's greenhouse gas rules have been filed. Any federal climate change legislation that is enacted may preempt the EPA's regulation of greenhouse gas emissions, including the Tailoring Rule, particularly as it relates to power plant greenhouse gas emissions. The extent to which the Tailoring Rule could have a material impact on our energy centers depends upon how state agencies apply the EPA's guidelines as to what constitutes the best available control technology for greenhouse gas emissions from power plants and whether physical changes or changes in operations subject to the rule occur at our energy centers. Although the EPA has stated its intention to regulate greenhouse gas emissions from stationary sources, such as power plants, congressional action could block or delay that effort.

Future federal and state legislation or regulations that mandate limits on the emission of greenhouse gases would likely result in significant increases in capital expenditures and operating costs, which, in turn, could lead to increased liquidity needs and higher financing costs. Moreover, to the extent Ameren Missouri requests recovery of these costs through rates, its regulators might delay or deny timely recovery of these costs. Excessive costs to comply with future legislation or regulations might force Ameren, Ameren Missouri and Genco as well as other similarly situated electric power generators to close some coal-fired facilities earlier than planned, which could lead to possible impairment of assets and reduced revenues. As a result, mandatory limits could have a material adverse impact on Ameren's, Ameren Missouri's, and Genco's results of operations, financial position, and liquidity.

Recent federal court decisions have considered the application of common law causes of action, such as nuisance, to address damages resulting from global climate change. In June 2011, the United States Supreme Court in State of Connecticut v. American Electric Power rejected state efforts to impose liability for CO₂ and greenhouse gases emissions under federal common law. That ruling, however, did not address whether private citizens could pursue causes of action based on state common law. In June 2011, a case called Comer v. Murphy Oil (Comer) was filed in the United States District Court for the Southern District of Mississippi. In this litigation, a Mississippi property owner sued several industrial companies, including Ameren Missouri and Genco, alleging that CO₂ emissions created the atmospheric conditions that intensified Hurricane Katrina. Although we are unable to predict the outcome of the Comer litigation on our results of operations, financial position, and liquidity, Ameren believes that it has meritorious defenses. Numerous procedural and substantive challenges are expected in the Comer litigation.

The impact on us of future initiatives related to greenhouse gas emissions and global climate change is unknown. Compliance costs could increase as future federal legislative, federal regulatory, and state-sponsored initiatives to control greenhouse gases continue to progress, making it more likely that some form of greenhouse gas emissions control will eventually be required. Since these initiatives continue to evolve, the impact on our coal-fired energy centers and our customers' costs is unknown, but any impact would probably be negative. Our costs of complying with any mandated federal or state greenhouse gas program could have a material impact on our future results of operations, financial position, and liquidity.

NSR and Clean Air Litigation

The EPA is engaged in an enforcement initiative to determine whether coal-fired power plants failed to comply with the requirements of the NSR and NSPS provisions under the Clean Air Act when the plants implemented modifications. The EPA's inquiries focus on whether projects performed at power plants should have triggered various permitting requirements and the installation of pollution control equipment.

In April 2005, Genco received a request from the EPA for information pursuant to Section 114(a) of the Clean Air Act. The request sought detailed operating and maintenance history data with respect to Genco's Coffeen, Hutsonville, Meredosia, Newton, and Joppa energy centers and AERG's E.D. Edwards and Duck Creek energy centers. In 2006, the EPA issued a second Section 114(a) request to Genco regarding projects at the Newton energy center. All of these facilities are coal-fired energy centers. In September 2008, the EPA issued a third Section 114(a) request regarding projects at all of Ameren's coal-fired energy centers in Illinois. We completed our response to the information requests, but we are unable to predict the outcome of this matter.

Following the issuance of a Notice of Violation, in January 2011, the Department of Justice on behalf of the EPA filed a complaint against Ameren Missouri in the United States District Court for the Eastern District of Missouri. The EPA's complaint alleges that in performing projects at its Rush Island coal-fired energy center, Ameren Missouri violated provisions of the Clean Air Act and Missouri law. In January 2012, the United States District Court granted, in part, Ameren Missouri's motion to dismiss various aspects of the EPA's penalty claims. The EPA's claims for injunctive relief, including to require the installation of pollution control equipment, remain. At present, the complaint does not include Ameren Missouri's other coal-fired energy centers, but the EPA has issued Notices of Violation under its NSR enforcement initiative against the company's Labadie, Meramec, and Sioux coal-fired energy centers. Litigation of this matter could take many years to resolve. Ameren Missouri believes its defenses to the allegations described in the complaint as well as the Notices of Violation are meritorious. Ameren Missouri will defend itself vigorously. However, there can be no assurances that it will be successful in its efforts.

Ultimate resolution of these matters could have a material adverse impact on the future results of operations, financial position, and liquidity of Ameren, Ameren Missouri and Genco. A resolution could result in increased capital expenditures for the installation of pollution control equipment, increased operations and maintenance expenses, and penalties. We are unable to predict the ultimate resolution of these matters or the costs that might be incurred. However, Ameren Missouri has concluded that, while a loss may be reasonably possible, the likelihood of loss is not probable. Therefore, no reserve has been established.

Clean Water Act

In March 2011, the EPA announced a proposed rule applicable to cooling water intake structures at existing power plants that have the ability to withdraw more than 2 million gallons of water per day from a body of water and use at least 25 percent of that water exclusively for cooling. Under the proposed rule, affected facilities would be required either to meet mortality limits for aquatic life impinged on the plant's intake screens or to reduce intake velocity to 0.5 feet per second. The proposed rule also requires plants to meet site-specific entrainment standards or to reduce the cooling water intake flow commensurate with the intake flow of a closed-cycle cooling system. The final rule is scheduled to be issued in July 2012, with compliance expected within eight years thereafter. All coal-fired, nuclear, and combined cycle energy centers at Ameren, Ameren Missouri and Genco with cooling water systems are subject to this proposed rule. The proposed rule did not mandate cooling towers at existing facilities, as other technology options potentially could meet the site-specific standards. Ameren, Ameren Missouri and Genco are currently evaluating the proposed rule, and their assessment of the proposed rule's impacts is ongoing. Therefore, we cannot predict at this time the capital or operating costs associated with compliance. The proposed rule could have an adverse effect on our results of operations, financial position, and liquidity if its implementation requires the installation of cooling towers at our electric generating stations.

In September 2009, the EPA announced its plan to revise the effluent guidelines applicable to steam electric generating units under the Clean Water Act. Effluent guidelines are national standards for wastewater discharges to surface water that are based on the effectiveness of available control technology. The EPA is engaged in information collection and analysis activities in support of this rulemaking. It has indicated that it expects to issue a proposed rule in July 2012 and to finalize the rule in 2014. We are unable at this time to predict the impact of this development.

Remediation

We are involved in a number of remediation actions to clean up hazardous waste sites as required by federal and state law. Such statutes require that responsible parties fund remediation actions regardless of their degree of fault, the legality of original disposal, or the ownership of a disposal site. Ameren Missouri and Ameren Illinois have each been identified by the federal or state governments as a potentially responsible party (PRP) at several contaminated sites. Several of these sites involve facilities that were transferred by our rate-regulated utility operations in Illinois to Genco in May 2000 and to AERG in October 2003. As part of each transfer, Ameren Illinois contractually agreed to indemnify Genco and AERG for remediation costs associated with preexisting environmental contamination at the transferred sites.

As of December 31, 2011, Ameren and Ameren Illinois owned or were otherwise responsible for 44 former MGP sites in Illinois. These are in various stages of investigation, evaluation, and remediation. Based on current estimated plans, Ameren and Ameren Illinois could substantially conclude remediation efforts at most of these sites by 2015. The ICC permits Ameren Illinois to recover remediation and litigation costs associated with its former MGP sites from its electric and natural gas utility customers through environmental adjustment rate riders. To be recoverable, such costs must be prudently and properly incurred. Costs are subject to annual review by the ICC.

As of December 31, 2011, Ameren and Ameren Missouri own or are otherwise responsible for 10 MGP sites in Missouri and one site in Iowa. Ameren Missouri does not currently have a rate rider mechanism that permits recovery of remediation costs associated with MGP sites from utility customers. Ameren Missouri does not have any retail utility operations in Iowa that would provide a source of recovery of these remediation costs.

The following table presents, as of December 31, 2011, the estimated probable obligation to remediate these MGP sites.

	Estimate				Recorded Liability(a)
	Low		High
Ameren	$	107	$	183	$	107
Ameren Missouri		3		4		3
Ameren Illinois		104		179		104

(a) Recorded liability represents the estimated minimum probable obligations, as no other amount within the range provided a better estimate.

Ameren Illinois is responsible for the cleanup of a former coal ash landfill in Coffeen, Illinois. As of December 31, 2011, Ameren Illinois estimated that obligation at $0.5 million to $6 million. Ameren Illinois recorded a liability of $0.5 million to represent its estimated minimum obligation for this site, as no other amount within the range was a better estimate. Ameren Illinois is also responsible for the cleanup of a landfill, underground storage tanks, and a water treatment plant in Illinois. As of December 31, 2011, Ameren Illinois recorded a liability of $0.8 million to represent its best estimate of the obligation for these sites.

Ameren Missouri has responsibility for the investigation and potential cleanup of two waste sites in Missouri as a result of federal agency mandates. One of the cleanup sites is a former coal tar distillery located in St. Louis, Missouri. In 2008, the EPA issued an administrative order to Ameren Missouri pertaining to this distillery operated by Koppers Company or its predecessor and successor companies. Ameren Missouri is the current owner of the site, but Ameren Missouri did not conduct any of the manufacturing operations involving coal tar or its byproducts. Ameren Missouri, along with two other PRPs, is currently performing a site investigation. As of December 31, 2011, Ameren Missouri estimated its obligation at $2 million to $5 million. Ameren Missouri has a liability of $2 million recorded to represent its estimated minimum obligation, as no other amount within the range was a better estimate. Ameren Missouri's other active federal agency-mandated cleanup site in Missouri is a site in Cape Girardeau. Ameren Missouri was a customer of an electrical equipment repair and disposal company that previously operated a facility at this site. A trust was established in the early 1990s by several businesses and governmental agencies to fund the cleanup of this site, which was completed in 2005. Ameren Missouri anticipates this trust fund will be sufficient to complete the remaining adjacent off-site cleanup and therefore has no recorded liability at December 31, 2011, related to this site.

Ameren Missouri also has a federal agency mandate to complete a site investigation for a site in Illinois. In 2000, the EPA notified Ameren Missouri and numerous other companies, including Solutia, that former landfills and lagoons in Sauget, Illinois, may contain soil and groundwater contamination. These sites are known as Sauget Area 2. From about 1926 until 1976, Ameren Missouri operated an energy center adjacent to Sauget Area 2. Ameren Missouri currently owns a parcel of property that was once used as a landfill. Under the terms of an Administrative Order on Consent, Ameren Missouri has joined with other PRPs to evaluate the extent of potential contamination with respect to Sauget Area 2.

The Sauget Area 2 investigations overseen by the EPA have been completed. The results have been submitted to the EPA, and a record of decision is expected in 2012. Once the EPA has selected a remedy, if any, it would begin negotiations with various PRPs regarding implementation. Over the last several years, numerous other parties have joined the PRP group. In addition, Pharmacia Corporation and Monsanto Company have agreed to assume the liabilities related to Solutia's former chemical waste landfill in the Sauget Area 2. As of December 31, 2011, Ameren Missouri estimated its obligation at $0.3 million to $10 million. Ameren Missouri has a liability of $0.3 million recorded to represent its estimated minimum obligation, as no other amount within the range was a better estimate.

In December 2004, AERG submitted a plan to the Illinois EPA to address groundwater and surface water issues associated with the recycle pond, ash ponds, and reservoir at the Duck Creek energy center. In 2010, AERG closed the recycle pond system. Remediation work on the recycle pond was completed in the first quarter of 2011, and therefore no liability exists as of December 31, 2011.

Our operations or those of our predecessor companies involve the use of, disposal of, and in appropriate circumstances, the cleanup of substances regulated under environmental protection laws. We are unable to determine whether such practices will result in future environmental commitments or affect our results of operations, financial position, or liquidity.

Ash Management

There has been activity at both state and federal levels regarding additional regulation of ash pond facilities and CCR. In May 2010, the EPA announced proposed new regulations regarding the regulatory framework for the management and disposal of CCR, which could affect future disposal and handling costs at our energy centers. Those proposed regulations include two options for managing CCRs under either solid or hazardous waste regulations, but either alternative would allow for some continued beneficial uses, such as recycling of CCR without classifying it as waste. As part of its proposal, the EPA is considering alternative regulatory approaches that require coal-fired power plants either to close surface impoundments, such as ash ponds, or to retrofit such facilities with liners. Existing impoundments and landfills used for the disposal of CCR would be subject to groundwater monitoring requirements and requirements related to closure and postclosure care under the proposed regulations. Additionally, in January 2010, EPA announced its intent to develop regulations establishing financial responsibility requirements for the electric generation industry, among other industries, and it specifically discussed CCR as a reason for developing the new requirements. Ameren, Ameren Missouri and Genco are currently evaluating all of the proposed regulations to determine whether current management of CCR, including beneficial reuse, and the use of the ash ponds should be altered. Ameren, Ameren Missouri and Genco also are evaluating the potential costs associated with compliance with the proposed regulation of CCR impoundments and landfills, which could be material, if such regulations are adopted.

In addition, the Illinois EPA requested that Ameren, Ameren Missouri and Genco establish groundwater monitoring plans for their ash impoundments in Illinois. Ameren and the Illinois EPA have established a framework for closure of ash ponds in Illinois, including the ash ponds at Venice, Hutsonville, and Duck Creek, when such facilities are ultimately taken out of service. Ameren, Ameren Missouri and Genco have recorded AROs, based on current laws, for the estimated costs of the retirement of their ash ponds.

Pumped-storage Hydroelectric Facility Breach

In December 2005, there was a breach of the upper reservoir at Ameren Missouri's Taum Sauk pumped-storage hydroelectric energy center. This resulted in significant flooding in the local area, which damaged a state park. Ameren Missouri settled with FERC and the state of Missouri all issues associated with the December 2005 Taum Sauk incident. The rebuilt Taum Sauk energy center became fully operational in April 2010.

Ameren Missouri included certain capitalized costs associated with enhancements, or costs that would have been incurred absent the breach, at the rebuilt Taum Sauk energy center not recovered from property insurers in its 2010 electric rate case filing. However, in the July 2011 rate order, the MoPSC disallowed all of these capitalized costs associated with the rebuilding of the Taum Sauk energy center. As a result of the order, Ameren and Ameren Missouri each recorded a pretax charge to earnings in 2011 of $89 million to reflect this disallowance. See Note 2 – Rate and Regulatory Matters for additional information about the appeal of the MoPSC's July 2011 electric rate order.

Ameren Missouri had property and liability insurance coverage for the Taum Sauk incident, subject to certain limits and deductibles. Insurance did not cover some lost electric margins or penalties paid to FERC. Ameren Missouri believes that the total cost for cleanup, damage and liabilities, excluding costs to rebuild the upper reservoir, is $209 million, which is the amount Ameren Missouri had paid as of December 31, 2011. As of December 31, 2011, Ameren Missouri had recorded expenses of $37 million, primarily in prior years (2011 – $1 million, 2010 – $1 million, 2009 – $2 million), for items not covered by insurance. Ameren Missouri recorded a $172 million receivable for amounts recoverable from insurance companies under liability coverage. As of December 31, 2011, Ameren Missouri had received $104 million from insurance companies for liability claims, which reduced the insurance receivable balance subject to liability coverage to $68 million.

In June 2010, Ameren Missouri sued an insurance company that was providing Ameren Missouri with liability coverage on the date of the Taum Sauk incident. In the litigation, filed in the United States District Court for the Eastern District of Missouri, Ameren Missouri claimed the insurance company breached its duty to indemnify Ameren Missouri for the losses experienced from the incident. In January 2011, the court ruled that the parties must first pursue alternative dispute resolution under the terms of their coverage agreement. In February 2011, Ameren Missouri filed an appeal of the January ruling with the United States Court of Appeals for the Eighth Circuit, seeking the ability to pursue resolution of this dispute outside of a dispute resolution process under the terms of its coverage agreement.

Until Ameren's remaining liability insurance claims and the related litigation are resolved, we are unable to determine the total impact the breach could have on Ameren's and Ameren Missouri's results of operations, financial position, and liquidity beyond those amounts already recognized.

Asbestos-related Litigation

Ameren, Ameren Missouri, Ameren Illinois and EEI have been named, along with numerous other parties, in a number of lawsuits filed by plaintiffs claiming varying degrees of injury from asbestos exposure. Most have been filed in the Circuit Court of Madison County, Illinois. The total number of defendants named in each case varies, with as many as 272 parties named in some pending cases and as few as two in others. In the cases pending as of December 31, 2011, the average number of parties was 80.

The claims filed against Ameren, Ameren Missouri, Ameren Illinois and Genco allege injury from asbestos exposure during the plaintiffs' activities at our present or former electric generating plants. Former CIPS plants are now owned by Genco, and former CILCO plants are now owned by AERG. As a part of the transfer of ownership of the CIPS and CILCO generating plants, CIPS and CILCO, now Ameren Illinois, contractually agreed to indemnify Genco and AERG, for liabilities associated with asbestos-related claims arising from activities prior to the transfer. Each lawsuit seeks unspecified damages that, if awarded at trial, typically would be shared among the various defendants.

The following table presents the pending asbestos-related lawsuits filed against the Ameren Companies as of December 31, 2011:

Ameren	Ameren Missouri	Ameren Illinois	Genco	Total(a)
4	53	77	(b)	93

(a) Total does not equal the sum of the subsidiary unit lawsuits because some of the lawsuits name multiple Ameren entities as defendants.

(b) As of December 31, 2011, six asbestos-related lawsuits were pending against EEI. The general liability insurance maintained by EEI provides coverage with respect to liabilities arising from asbestos-related claims.

At December 31, 2011, Ameren, Ameren Missouri, Ameren Illinois and Genco had liabilities of $18 million, $6 million, $12 million, and $- million, respectively, recorded to represent their best estimate of their obligations related to asbestos claims.

Ameren Illinois has a tariff rider to recover the costs of asbestos-related litigation claims, subject to the following terms: 90% of cash expenditures in excess of the amount included in base electric rates are to be recovered from a trust fund that was established when Ameren acquired IP. At December 31, 2011, the trust fund balance was $23 million, including accumulated interest. If cash expenditures are less than the amount in base rates, Ameren Illinois will contribute 90% of the difference to the fund. Once the trust fund is depleted, 90% of allowed cash expenditures in excess of base rates will be recovered through charges assessed to customers under the tariff rider. Following the Ameren Illinois Merger, this rider is applicable only for claims that occurred within IP's historical service territory. Similarly, the rider will permit recovery only from customers within IP's historical service territory.

Illinois Sales and Use Tax Exemptions and Credits

In Exelon Corporation v. Department of Revenue, the Illinois Supreme Court decided in 2009 that electricity is tangible personal property for purposes of the Illinois income tax investment credit. In March 2010, the United States Supreme Court refused to hear the case, and the decision became final. During the second quarter of 2010, Genco and AERG began claiming Illinois sales and use tax exemptions and credits for purchase transactions related to their generation operations. The basis for those claims is that the determination in the Exelon case that electricity is tangible personal property applies to sales and use tax manufacturing exemptions and credits. On November 2, 2011, EEI received a notice of proposed tax liability, documenting the state of Illinois' position that EEI did not qualify for the manufacturing exemption it used during 2010. Genco is challenging the State of Illinois' position. In December 2011, EEI filed a request for review by the Informal Conference Board of the Illinois Department of Revenue. Ameren and Genco do not believe that it is probable that the state of Illinois will prevail and therefore have not recorded a charge to earnings for the loss contingency. From the second quarter of 2010 through December 31, 2011, Ameren and Genco claimed manufacturing exemptions and credits of $27 million and $19 million, respectively.

Ameren Illinois Company [Member]

Commitments And Contingencies

NOTE 15 – COMMITMENTS AND CONTINGENCIES

We are involved in legal, tax and regulatory proceedings before various courts, regulatory commissions, and governmental agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in these notes to our financial statements, will not have a material adverse effect on our results of operations, financial position, or liquidity.

See also Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 10 – Callaway Energy Center and Note 14 – Related Party Transactions in this report.

Callaway Energy Center

The following table presents insurance coverage at Ameren Missouri's Callaway energy center at December 31, 2011. The property coverage and the nuclear liability coverage must be renewed on April 1 and January 1, respectively, of each year.

Type and Source of Coverage	Maximum Coverages			Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers	$	375			$        -
Pool participation		12,219	(a)		118	(b)
	$	12,594	(c)		$   118
Property damage:
Nuclear Electric Insurance Ltd.	$	2,750	(d)		$     23
Replacement power:
Nuclear Electric Insurance Ltd	$	490	(e)		$       9
Energy Risk Assurance Company	$	64	(f)		$        -

(a) Provided through mandatory participation in an industrywide retrospective premium assessment program.

(b) Retrospective premium under Price-Anderson. This is subject to retrospective assessment with respect to a covered loss in excess of $375 million in the event of an incident at any licensed U.S. commercial reactor, payable at $17.5 million per year.

(c) Limit of liability for each incident under the Price-Anderson liability provisions of the Atomic Energy Act of 1954, as amended. A company could be assessed up to $118 million per incident for each licensed reactor it operates with a maximum of $17.5 million per incident to be paid in a calendar year for each reactor. This limit is subject to change to account for the effects of inflation and changes in the number of licensed reactors.

(d) Provides for $500 million in property damage and decontamination, excess property insurance, and premature decommissioning coverage up to $2.25 billion for losses in excess of the $500 million primary coverage.

(e) Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. Weekly indemnity up to $4.5 million for 52 weeks, which commences after the first eight weeks of an outage, plus up to $3.6 million per week for a minimum of 71 weeks thereafter for a total not exceeding the policy limit of $490 million.

(f) Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. The coverage commences after the first 52 weeks of insurance coverage from Nuclear Electric Insurance Ltd. and is for a weekly indemnity of $900,000 for 71 weeks in excess of the $3.6 million per week set forth above. Energy Risk Assurance Company is an affiliate and has reinsured this coverage with third-party insurance companies. See Note 14 – Related Party Transactions for more information on this affiliate transaction.

The Price-Anderson Act is a federal law that limits the liability for claims from an incident involving any licensed United States commercial nuclear power facility. The limit is based on the number of licensed reactors. The limit of liability and the maximum potential annual payments are adjusted at least every five years for inflation to reflect changes in the Consumer Price Index. The five-year inflationary adjustment as prescribed by the most recent Price-Anderson Act renewal was effective October 29, 2008. Owners of a nuclear reactor cover this exposure through a combination of private insurance and mandatory participation in a financial protection pool, as established by Price-Anderson.

Losses resulting from terrorist attacks are covered under Nuclear Electric Insurance Ltd.'s policies, subject to an industrywide aggregate policy limit of $3.24 billion within a 12-month period for coverage for such terrorist acts.

If losses from a nuclear incident at the Callaway energy center exceed the limits of, or are not covered by, insurance, or if coverage is unavailable, Ameren Missouri is at risk for any uninsured losses. If a serious nuclear incident were to occur, it could have a material adverse effect on Ameren's and Ameren Missouri's results of operations, financial position, or liquidity.

Leases

We lease various facilities, office equipment, plant equipment, and rail cars under operating leases. The following table presents our lease obligations at December 31, 2011:

	Total		2012		2013		2014		2015		2016		After 5 Years
Ameren:(a)
Capital lease payments(b)	$	621	$	33	$	32	$	32	$	33	$	33	$	458
Less amount representing interest		312		28		27		27		27		27		176
Present value of minimum capital lease payments	$	309	$	5	$	5	$	5	$	6	$	6	$	282
Operating leases(c)		307		38		32		26		26		25		160
Total lease obligations	$	616	$	43	$	37	$	31	$	32	$	31	$	442
Ameren Missouri:
Capital lease payments(b)	$	621	$	33	$	32	$	32	$	33	$	33	$	458
Less amount representing interest		312		28		27		27		27		27		176
Present value of minimum capital lease payments	$	309	$	5	$	5	$	5	$	6	$	6	$	282
Operating leases(c)		134		13		12		12		12		12		73
Total lease obligations	$	443	$	18	$	17	$	17	$	18	$	18	$	355
Ameren Illinois:
Operating leases(c)	$	7	$	1	$	1	$	1	$	1	$	1	$	2
Genco:
Operating leases(c)	$	131	$	11	$	11	$	11	$	10	$	11	$	77

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

(b) See Properties under Part I, Item 2, and Note 3 – Property and Plant, Net of this report for additional information.

(c) Amounts related to certain real estate leases and railroad licenses have indefinite payment periods. Ameren's $2 million annual obligation for these items is included in the 2012 through 2016 columns. The amounts for the indefinite payments are not included in the After 5 Years column because that period is indefinite.

The following table presents total rental expense, included in operating expenses, for the years ended December 31, 2011, 2010 and 2009:

	2011		2010		2009
Ameren(a)	$	47	$	52	$	50
Ameren Missouri		29		29		30
Ameren Illinois		17		19		19
Genco		12		13		15

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

Other Obligations

To supply a portion of the fuel requirements of our generating plants, we have entered into various long-term commitments for the procurement of coal, natural gas, nuclear fuel, and methane gas. We also have entered into various long-term commitments for purchased power and natural gas for distribution. The table below presents our estimated fuel, purchased power, and other commitments at December 31, 2011. Ameren's and Ameren Missouri's coal commitments include multiyear agreements to procure ultra-low-sulfur coal and related transportation from the Powder River Basin in Wyoming. Ameren's and Ameren Missouri's purchased power obligations include a 102-MW power purchase agreement with a wind farm operator that expires in 2024. Ameren's and Ameren Illinois' purchased power obligations include the Ameren Illinois power purchase agreements entered into as part of the IPA-administered power procurement process. Included in the Other column are minimum purchase commitments under contracts for equipment, design and construction, meter reading services, and an Ameren tax credit obligation at December 31, 2011. Ameren's tax credit obligation is a $17 million note payable issued for an investment in a commercial real estate development partnership to acquire tax credits. This note payable was netted against the related investment in "Other assets" on Ameren's balance sheet at December 31, 2011, as Ameren has a legally enforceable right to offset under authoritative accounting guidance.

	Coal		Natural Gas		Nuclear Fuel		Purchased Power		Methane Gas		Other		Total
Ameren:(a)
2012	$	1,120	$	398	$	36	$	196	$	1	$	221	$	1,972
2013		792		295		37		309		3		80		1,516
2014		692		220		96		125		3		75		1,211
2015		687		116		90		51		3		52		999
2016		674		39		100		52		3		62		930
Thereafter		968		134		298		746		94		246		2,486
Total	$	4,933	$	1,202	$	657	$	1,479	$	107	$	736	$	9,114
Ameren Missouri:
2012	$	623	$	63	$	36	$	19	$	1	$	78	$	820
2013		605		48		37		19		3		50		762
2014		625		36		96		19		3		47		826
2015		614		19		90		19		3		28		773
2016		644		7		100		19		3		38		811
Thereafter		921		30		298		155		94		144		1,642
Total	$	4,032	$	203	$	657	$	250	$	107	$	385	$	5,634
Ameren Illinois:
2012	$	-	$	324	$	-	$	177	$	-	$	24	$	525
2013		-		243		-		290		-		22		555
2014		-		180		-		106		-		22		308
2015		-		94		-		32		-		24		150
2016		-		31		-		33		-		24		88
Thereafter		-		105		-		591		-		102		798
Total	$	-	$	977	$	-	$	1,229	$	-	$	218	$	2,424
Genco:
2012	$	355	$	9	$	-	$	-	$	-	$	98	$	462
2013		108		4		-		-		-		5		117
2014		40		3		-		-		-		5		48
2015		45		2		-		-		-		-		47
2016		-		-		-		-		-		-		-
Thereafter		-		-		-		-		-		-		-
Total	$	548	$	18	$	-	$	-	$	-	$	108	$	674

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

Also, as part of the 2007 Illinois Electric Settlement Agreement, Ameren Illinois entered into financial contracts with Marketing Company to lock in energy prices for 400 to 1,000 megawatts annually of their round-the-clock power requirements from 2008 to 2012. These commitments are not reflected in the above table. See Note 7 – Derivative Financial Instruments and Note 14 – Related Party Transactions for additional information.

In February 2012, a rate stability procurement for energy products and renewable energy credits was administered by the IPA for the June 2013 through May 2017 period to meet certain requirements for purchased power related to the IEIMA. Ameren Illinois contracted to purchase approximately 13 million megawatthours of energy products at an average price of approximately $31 per megawatthour. Ameren Illinois is currently reviewing the results of the renewable energy credits procurement proceeding.

Ameren Illinois has entered into an agreement to purchase approximately 15.5 billion cubic feet of synthetic natural gas annually over a 10-year period beginning in 2016 for its natural gas customers. The agreement is contingent on the counterparty reaching certain milestones during the project development and the construction of the plant that will produce the synthetic natural gas. Construction has not begun on the plant; therefore, Ameren Illinois' obligations are not yet certain at this time. The agreement was entered into pursuant to an Illinois law which became effective August 2, 2011, and provides that all contract costs for synthetic natural gas incurred by Ameren Illinois are reasonable and prudent and recoverable through the PGA and are not subject to review or disallowance by the ICC.

Environmental Matters

We are subject to various environmental laws and regulations enforced by federal, state, and local authorities. From the beginning phases of siting and development to the ongoing operation of existing or new electric generating, transmission and distribution facilities, natural gas storage, transmission and distribution facilities, our activities involve compliance with diverse environmental laws and regulations. These laws and regulations address emissions, impacts to air, land and water, noise, protected natural and cultural resources (such as wetlands, endangered species and other protected wildlife, and archeological and historical resources), and chemical and waste handling. Complex and lengthy processes are required to obtain approvals, permits, or licenses for new, existing or modified facilities. Additionally, the use and handling of various chemicals or hazardous materials (including wastes) requires release prevention plans and emergency response procedures.

In addition to existing laws and regulations, including the Illinois MPS that applies to our energy centers in Illinois, the EPA is developing numerous new environmental regulations that will have a significant impact on the electric utility industry. These regulations could be particularly burdensome for certain companies, including Ameren, Ameren Missouri and Genco, that operate coal-fired energy centers. Significant new rules proposed or promulgated since the beginning of 2010 include the regulation of greenhouse gas emissions; revised national ambient air quality standards for SO₂ and NO₂ emissions; the CSAPR, which requires further reductions of SO₂ and NO_x emissions from power plants; a regulation governing management of CCR and coal ash impoundments; the MATS, which requires reduction of emissions of mercury, toxic metals, and acid gases from power plants; revised NSPS for particulate matter, SO₂, and NO_x emissions from new sources; and new regulations under the Clean Water Act that could require significant capital expenditures such as new water intake structures or cooling towers at our energy centers. The EPA also plans to propose an additional rule, applicable to new and existing electric generating units, governing NSPS and emission guidelines for greenhouse gas emissions. These new regulations may be litigated, so the timing of their implementation is uncertain, as evidenced by the stay of the CSAPR by the United States Court of Appeals for the District of Columbia on December 30, 2011. Although many details of these future regulations are unknown, the combined effects of the new and proposed environmental regulations may result in significant capital expenditures and/or increased operating costs over the next five to ten years for Ameren, Ameren Missouri and Genco. Actions required to ensure that our facilities and operations are in compliance with environmental laws and regulations could be prohibitively expensive. If they are, these regulations could require us to close or to significantly alter the operation of our energy centers, which could have an adverse effect on our results of operations, financial position, and liquidity, including the impairment of plant assets. Failure to comply with environmental laws and regulations might also result in the imposition of fines, penalties, and injunctive measures.

The estimates in the table below contain all of the known capital costs to comply with existing environmental regulations and our assessment of the potential impacts of the EPA's proposed regulation for CCR, the recently finalized MATS, the stayed CSAPR as currently designed, and the revised national ambient air quality standards for SO₂ and NO_x emissions as of December 31, 2011. The estimates in the table below assume that CCR will continue to be regarded as nonhazardous. The estimates in the table below do not include the impacts of new regulations proposed by the EPA under the Clean Water Act in March 2011 regarding cooling water intake structures as our evaluation of those impacts is ongoing. The estimates shown in the table below could change significantly depending upon a variety of factors including:

Ÿ additional federal or state requirements;

Ÿ regulation of greenhouse gas emissions;

Ÿ new national ambient air quality standards or changes to existing standards for ozone, fine particulates, SO₂, and NO_x emissions;

Ÿ additional rules governing air pollutant transport;

Ÿ finalized regulations under the Clean Water Act;

Ÿ CCR being classified as hazardous;

Ÿ whether the CSAPR is implemented and whether any modifications are made to its existing requirements;

Ÿ new technology;

Ÿ expected power prices;

Ÿ variations in costs of material or labor; and

Ÿ alternative compliance strategies or investment decisions.

	2012		2013 - 2016				2017 - 2021				Total
AMO(a)	$	55	$	325 -	$	400	$	845 -	$	1,030	$	1,225 -	$	1,485
Genco		150		100 -		125		245 -		295		495 -		570
AERG		5		20 -		25		80 -		100		105 -		130
Ameren	$	210	$	445 -	$	550	$	1,170 -	$	1,425	$	1,825 -	$	2,185

(a) Ameren Missouri's expenditures are expected to be recoverable from ratepayers.

The decision to make pollution control equipment investments at our Merchant Generation business depends on whether the expected future market price for power reflects the increased cost for environmental compliance. In early 2012, there has been a decline in the market price for wholesale power because of factors such as declining natural gas prices and the stay of the CSAPR. As a result of this decline in the market price for power, as well as uncertain environmental regulations, Genco is decelerating the construction of two scrubbers at of its Newton energy center. These scrubbers were originally expected to be installed in late 2013 and spring 2014. The ultimate installation of these scrubbers, now estimated to occur between 2017 and 2021 in the table above, has been postponed until such time as the incremental investment necessary for completion is justified by visible market conditions. However, Genco will continue to incur capital costs related to the construction of these scrubbers. The table above includes Genco's estimated costs of approximately $150 million in 2012 and approximately $20 million annually, excluding capitalized interest, from 2013 through 2016 for the construction of the two scrubbers. In addition to Genco's reduction in estimated capital expenditures, AERG is deferring precipitator upgrades at its E.D. Edwards energy center beyond 2016.

The following sections describe the more significant environmental rules that affect our operations.

Clean Air Act

Both federal and state laws require significant reductions in SO₂ and NO_x emissions that result from burning fossil fuels. In March 2005, the EPA issued regulations with respect to SO₂ and NO_x emissions (the CAIR). The CAIR required generating facilities in 28 states, including Missouri and Illinois, and the District of Columbia to participate in cap-and-trade programs to reduce annual SO₂ emissions, annual NO_x emissions, and ozone season NO_x emissions.

In December 2008, the United States Court of Appeals for the District of Columbia remanded the CAIR to the EPA for further action to remedy the rule's flaws, but allowed the CAIR's cap-and-trade programs to remain effective until they are replaced by the EPA. In July 2011, the EPA issued the CSAPR as the CAIR replacement. The CSAPR was to become effective on January 1, 2012, for SO₂ and annual NO_x reductions and on May 1, 2012, for ozone season NO_x reductions. In the CSAPR, the EPA developed federal implementation plans for each state covered by this rule; however, each impacted state can develop its own implementation rule starting as early as 2013. The CSAPR establishes emission allowance budgets for each of the states subject to the regulation, including Missouri and Illinois. With the CSAPR, the EPA abandoned CAIR's regional approach to cutting emissions and instead set a pollution budget for each of the impacted states based on the EPA's analysis of each upwind state's contribution to air quality in downwind states. For Missouri and Illinois, emission reductions were required in two phases beginning in 2012, with further reductions in 2014. With the CSAPR, the EPA adopted a cap-and-trade approach that allows intrastate and limited interstate trading of emission allowances with other sources within the same program, that is, in the SO₂ program, in the annual NO_x, or in ozone season NO_x program. Multiple legal challenges were filed requesting to have CSAPR partially or entirely vacated and to stay the implementation of the CSAPR while the court considers the challenges. On December 30, 2011, the United States Court of Appeals for the District of Columbia issued a stay of the CSAPR. The stay does not invalidate the rule, but only delays its implementation until a final court ruling is issued. The United States Court of Appeals for the District of Columbia has expedited its consideration of the regulation and will hear arguments on the validity of CSAPR in April 2012. The ultimate outcome of the challenges to the regulation is uncertain. The court could uphold CSAPR or remand it back to the EPA for partial or entire revision. Until the CSAPR appeal process is concluded, the EPA will continue to administer the CAIR.

On December 21, 2011, the EPA issued the final MATS under the Clean Air Act, which require emission reductions for mercury and other hazardous air pollutants, such as acid gases, toxic metals, and particulate matter by setting emission limits equal to the average emissions of the best performing 12% of existing coal and oil-fired electric generating units. Also, the rule requires reductions in hydrogen chloride emissions, which were not regulated previously, and it may require continuous monitoring systems that are not currently in place. The MATS do not require a specific control technology to achieve the emission reductions. The MATS will apply to each unit at a coal-fired power plant; however, emission compliance can be averaged for the entire power plant. Compliance is required by April 2015 or, with a case-by-case extension, by April 2016.

Separately, in January and June 2010, the EPA finalized new ambient air quality standards for SO₂ and NO₂. It also announced plans for further reductions in the annual national ambient air quality standards for ozone and fine particulates. The state of Illinois and the state of Missouri will be required to develop separate attainment plans to comply with the new ambient air quality standards. Ameren, Ameren Missouri and Genco continue to assess the impacts of these new standards. In September 2011, the EPA withdrew its draft annual national ambient air quality standard for ozone and announced that it was implementing the 2008 national ambient air quality standard for ozone. The EPA is required to revisit this standard again in 2013.

Ameren Missouri's current environmental compliance plan for air emissions from its energy centers includes burning ultra-low-sulfur coal and installing new or optimizing existing pollution control equipment. In July 2011, Ameren Missouri contracted to procure significantly higher volumes of lower-sulfur-content coal than Ameren Missouri's energy centers have historically burned, which will allow Ameren Missouri to eliminate or postpone capital expenditures for pollution control equipment while still achieving required emissions levels. In 2010, Ameren Missouri completed the installation of two scrubbers at its Sioux energy center to reduce SO₂ emissions. Currently, Ameren Missouri's compliance plan assumes the installation of two scrubbers within its coal-fired fleet during the next 10 years and precipitator upgrades at multiple energy centers. However, Ameren Missouri is currently evaluating its operations and options to determine how to comply with the additional emission reductions requirements in 2014 set forth in the CSAPR, if ultimately enacted, the MATS, and other recently finalized or proposed EPA regulations.

Existing Illinois state regulations already required Ameren and Genco to reduce their emissions of mercury under the MPS. Ameren's and Genco's review of the MATS indicates that the scope of the federal standards is broader than the MPS, as no exemption exists for smaller coal-fired plants. Additionally, the MATS are more stringent than the MPS because compliance with the MATS is measured on a quarterly basis and, in some cases, a thirty-day rolling basis and not annually, as allowed under state requirements. At the end of 2011, Genco ceased operations of its Meredosia and Hutsonville energy centers. The closure of these energy centers was primarily due to the expected cost of complying with CSAPR and MATS. See Note 17 – Goodwill, Impairment and Other Charges for additional information.

Genco and AERG expect to install additional, or optimize existing, pollution control equipment, or modify operations to meet new and incremental emission reduction requirements under the MPS, the MATS, or the CSAPR as they become effective. Under the MPS, as amended, Illinois generators are required to reduce mercury, SO₂, and NO_x emissions by 2015. To comply with the MPS and other air emissions laws and regulations, Genco and AERG are installing equipment designed to reduce their emissions of mercury, NO_x, and SO₂. Genco and AERG have installed a total of three scrubbers at two energy centers. Two additional scrubbers are being constructed at Genco's Newton energy center. As discussed above, the timing of the installation of these scrubbers as well as precipitator upgrades at AERG's E.D. Edwards energy center have been extended. The closure of Genco's Meredosia and Hutsonville energy centers will allow the Merchant Generation segment additional flexibility in the methods to achieve compliance with environmental standards. Merchant Generation and Genco will continue to review and adjust their compliance plans in light of evolving outlooks for power and capacity prices, delivered fuel costs, environment standards and compliance technologies, among other factors.

The completion of Ameren's, Ameren Missouri's and Genco's review of recently finalized environmental regulations and compliance measures could result in significant increases in capital expenditures and operating costs. The compliance costs could be prohibitive at some of our energy centers as the expected return from these investments, at current market prices for energy and capacity, might not justify the required capital expenditures or their continued operation, which could result in the impairment of long-lived assets.

Emission Allowances

The Clean Air Act created marketable commodities called allowances under the acid rain program, the NO_x budget trading program, the CAIR, and the CSAPR. With the CSAPR, the EPA adopted a cap-and-trade approach that allows intrastate and limited interstate trading of emission allowances with other sources within the same program, that is, either the SO₂, annual NO_x, or ozone season NO_x programs. As noted above, on December 30, 2011, the United States Court of Appeals for the District of Columbia issued a stay of the CSAPR. Until the CSAPR appeal process is concluded, the EPA will continue to administer the CAIR including its allowance program. See Note 1 – Summary of Significant Accounting Policies for the SO₂ and NO_x emission allowance book values that were classified as intangible assets as of December 31, 2011 and 2010, and Note 17 – Goodwill, Impairment and Other Charges for information regarding the emission allowance impairments recorded during 2011 and 2010.

Environmental regulations including the CAIR and the CSAPR, the timing of the installation of pollution control equipment, fuel mix, and the level of operations, will have a significant impact on the number of allowances required for ongoing operations. The CAIR uses the acid rain program's allowances for SO₂ emissions and created annual and ozone season NO_x allowances. The CSAPR, however, will not rely upon the acid rain program, the NO_x budget trading program, or CAIR allowances for its allowance allocation program. Instead, the EPA issued a new type of emissions allowance for each program under the CSAPR. Any unused SO₂ allowances, annual NO_x allowances, and ozone season NO_x allowances issued under CAIR cannot be used for compliance with CSAPR. Ameren, Ameren Missouri and Genco expect to have adequate CAIR allowances for 2012 to avoid needing to make external purchases.

Should the CSAPR become effective as issued, Ameren, Ameren Missouri and Genco are studying their compliance options to identify additional opportunities that may exist for compliance in an economical fashion. Ameren, Ameren Missouri and Genco may be required to purchase emission allowances, if available, to install new or optimize existing pollution control equipment, to limit generation, or take other actions to achieve compliance with the CSAPR in future phase-in years.

Global Climate Change

State and federal authorities, including the United States Congress, have considered initiatives to limit greenhouse gas emissions and to address global climate change. Potential impacts from any climate change legislation or regulation could vary, depending upon proposed CO₂ emission limits, the timing of implementation of those limits, the method of distributing any allowances, the degree to which offsets are allowed and available, and provisions for cost-containment measures, such as a "safety valve" provision that provides a maximum price for emission allowances. As a result of our diverse fuel portfolio, our emissions of greenhouse gases vary among our energy centers, but coal-fired power plants are significant sources of CO₂. The enactment of a climate change law could result in a significant rise in household costs and rates for electricity could rise significantly. The burden could fall particularly hard on electricity consumers and upon the economy in the Midwest because of the region's reliance on electricity generated by coal-fired power plants. Natural gas emits about half as much CO₂ as coal when burned to produce electricity. Therefore, climate change regulation could cause the conversion of coal-fired power plants to natural gas, or the construction of new natural gas plants to replace coal-fired power plants. As a result, economywide shifts to natural gas as a fuel source for electricity generation also could affect the cost of heating for our utility customers and many industrial processes that use natural gas.

In December 2009, the EPA issued its "endangerment finding" under the Clean Air Act which stated that greenhouse gas emissions, including CO₂, endanger human health and welfare and that emissions of greenhouse gases from motor vehicles contribute to that endangerment. In March 2010, the EPA issued a determination that greenhouse gas emissions from stationary sources, such as power plants, would be subject to regulation under the Clean Air Act effective the beginning of 2011. As a result of these actions, we are required to consider the emissions of greenhouse gases in any air permit application.

Recognizing the difficulties presented by regulating at once virtually all emitters of greenhouse gases, the EPA finalized in May 2010 regulations, known as the "Tailoring Rule," that established new higher thresholds for regulating greenhouse gas emissions from stationary sources, such as power plants. The Tailoring Rule became effective in January 2011. The rule requires any source that already has an operating permit to have greenhouse-gas-specific provisions added to its permits upon renewal. Currently, all Ameren energy centers have operating permits that, when renewed, may be modified to address greenhouse gas emissions. The Tailoring Rule also provides that if projects performed at major sources result in an increase in emissions of greenhouse gases of at least 75,000 tons per year, measured in CO₂ equivalents, such projects could trigger permitting requirements under the NSR programs and the application of best available control technology, if any, to control greenhouse gas emissions. New major sources are also required to obtain such a permit and to install the best available control technology if their greenhouse gas emissions exceed the applicable emissions threshold. Separately, in December 2010, the EPA announced a settlement agreement under which it would propose NSPS for greenhouse gas emissions at new and existing fossil fuel-fired power plants by July 26, 2011 and issue a final standard by May 2012. The EPA has not yet proposed a rule and has not specified a new estimate of when it will issue that standard. It is uncertain whether reductions to greenhouse gas emissions would be required at Ameren's, Ameren Missouri's or Genco's energy centers as a result of any of the EPA's new and future rules. Legal challenges to the EPA's greenhouse gas rules have been filed. Any federal climate change legislation that is enacted may preempt the EPA's regulation of greenhouse gas emissions, including the Tailoring Rule, particularly as it relates to power plant greenhouse gas emissions. The extent to which the Tailoring Rule could have a material impact on our energy centers depends upon how state agencies apply the EPA's guidelines as to what constitutes the best available control technology for greenhouse gas emissions from power plants and whether physical changes or changes in operations subject to the rule occur at our energy centers. Although the EPA has stated its intention to regulate greenhouse gas emissions from stationary sources, such as power plants, congressional action could block or delay that effort.

Future federal and state legislation or regulations that mandate limits on the emission of greenhouse gases would likely result in significant increases in capital expenditures and operating costs, which, in turn, could lead to increased liquidity needs and higher financing costs. Moreover, to the extent Ameren Missouri requests recovery of these costs through rates, its regulators might delay or deny timely recovery of these costs. Excessive costs to comply with future legislation or regulations might force Ameren, Ameren Missouri and Genco as well as other similarly situated electric power generators to close some coal-fired facilities earlier than planned, which could lead to possible impairment of assets and reduced revenues. As a result, mandatory limits could have a material adverse impact on Ameren's, Ameren Missouri's, and Genco's results of operations, financial position, and liquidity.

Recent federal court decisions have considered the application of common law causes of action, such as nuisance, to address damages resulting from global climate change. In June 2011, the United States Supreme Court in State of Connecticut v. American Electric Power rejected state efforts to impose liability for CO₂ and greenhouse gases emissions under federal common law. That ruling, however, did not address whether private citizens could pursue causes of action based on state common law. In June 2011, a case called Comer v. Murphy Oil (Comer) was filed in the United States District Court for the Southern District of Mississippi. In this litigation, a Mississippi property owner sued several industrial companies, including Ameren Missouri and Genco, alleging that CO₂ emissions created the atmospheric conditions that intensified Hurricane Katrina. Although we are unable to predict the outcome of the Comer litigation on our results of operations, financial position, and liquidity, Ameren believes that it has meritorious defenses. Numerous procedural and substantive challenges are expected in the Comer litigation.

The impact on us of future initiatives related to greenhouse gas emissions and global climate change is unknown. Compliance costs could increase as future federal legislative, federal regulatory, and state-sponsored initiatives to control greenhouse gases continue to progress, making it more likely that some form of greenhouse gas emissions control will eventually be required. Since these initiatives continue to evolve, the impact on our coal-fired energy centers and our customers' costs is unknown, but any impact would probably be negative. Our costs of complying with any mandated federal or state greenhouse gas program could have a material impact on our future results of operations, financial position, and liquidity.

NSR and Clean Air Litigation

The EPA is engaged in an enforcement initiative to determine whether coal-fired power plants failed to comply with the requirements of the NSR and NSPS provisions under the Clean Air Act when the plants implemented modifications. The EPA's inquiries focus on whether projects performed at power plants should have triggered various permitting requirements and the installation of pollution control equipment.

In April 2005, Genco received a request from the EPA for information pursuant to Section 114(a) of the Clean Air Act. The request sought detailed operating and maintenance history data with respect to Genco's Coffeen, Hutsonville, Meredosia, Newton, and Joppa energy centers and AERG's E.D. Edwards and Duck Creek energy centers. In 2006, the EPA issued a second Section 114(a) request to Genco regarding projects at the Newton energy center. All of these facilities are coal-fired energy centers. In September 2008, the EPA issued a third Section 114(a) request regarding projects at all of Ameren's coal-fired energy centers in Illinois. We completed our response to the information requests, but we are unable to predict the outcome of this matter.

Following the issuance of a Notice of Violation, in January 2011, the Department of Justice on behalf of the EPA filed a complaint against Ameren Missouri in the United States District Court for the Eastern District of Missouri. The EPA's complaint alleges that in performing projects at its Rush Island coal-fired energy center, Ameren Missouri violated provisions of the Clean Air Act and Missouri law. In January 2012, the United States District Court granted, in part, Ameren Missouri's motion to dismiss various aspects of the EPA's penalty claims. The EPA's claims for injunctive relief, including to require the installation of pollution control equipment, remain. At present, the complaint does not include Ameren Missouri's other coal-fired energy centers, but the EPA has issued Notices of Violation under its NSR enforcement initiative against the company's Labadie, Meramec, and Sioux coal-fired energy centers. Litigation of this matter could take many years to resolve. Ameren Missouri believes its defenses to the allegations described in the complaint as well as the Notices of Violation are meritorious. Ameren Missouri will defend itself vigorously. However, there can be no assurances that it will be successful in its efforts.

Ultimate resolution of these matters could have a material adverse impact on the future results of operations, financial position, and liquidity of Ameren, Ameren Missouri and Genco. A resolution could result in increased capital expenditures for the installation of pollution control equipment, increased operations and maintenance expenses, and penalties. We are unable to predict the ultimate resolution of these matters or the costs that might be incurred. However, Ameren Missouri has concluded that, while a loss may be reasonably possible, the likelihood of loss is not probable. Therefore, no reserve has been established.

Clean Water Act

In March 2011, the EPA announced a proposed rule applicable to cooling water intake structures at existing power plants that have the ability to withdraw more than 2 million gallons of water per day from a body of water and use at least 25 percent of that water exclusively for cooling. Under the proposed rule, affected facilities would be required either to meet mortality limits for aquatic life impinged on the plant's intake screens or to reduce intake velocity to 0.5 feet per second. The proposed rule also requires plants to meet site-specific entrainment standards or to reduce the cooling water intake flow commensurate with the intake flow of a closed-cycle cooling system. The final rule is scheduled to be issued in July 2012, with compliance expected within eight years thereafter. All coal-fired, nuclear, and combined cycle energy centers at Ameren, Ameren Missouri and Genco with cooling water systems are subject to this proposed rule. The proposed rule did not mandate cooling towers at existing facilities, as other technology options potentially could meet the site-specific standards. Ameren, Ameren Missouri and Genco are currently evaluating the proposed rule, and their assessment of the proposed rule's impacts is ongoing. Therefore, we cannot predict at this time the capital or operating costs associated with compliance. The proposed rule could have an adverse effect on our results of operations, financial position, and liquidity if its implementation requires the installation of cooling towers at our electric generating stations.

In September 2009, the EPA announced its plan to revise the effluent guidelines applicable to steam electric generating units under the Clean Water Act. Effluent guidelines are national standards for wastewater discharges to surface water that are based on the effectiveness of available control technology. The EPA is engaged in information collection and analysis activities in support of this rulemaking. It has indicated that it expects to issue a proposed rule in July 2012 and to finalize the rule in 2014. We are unable at this time to predict the impact of this development.

Remediation

We are involved in a number of remediation actions to clean up hazardous waste sites as required by federal and state law. Such statutes require that responsible parties fund remediation actions regardless of their degree of fault, the legality of original disposal, or the ownership of a disposal site. Ameren Missouri and Ameren Illinois have each been identified by the federal or state governments as a potentially responsible party (PRP) at several contaminated sites. Several of these sites involve facilities that were transferred by our rate-regulated utility operations in Illinois to Genco in May 2000 and to AERG in October 2003. As part of each transfer, Ameren Illinois contractually agreed to indemnify Genco and AERG for remediation costs associated with preexisting environmental contamination at the transferred sites.

As of December 31, 2011, Ameren and Ameren Illinois owned or were otherwise responsible for 44 former MGP sites in Illinois. These are in various stages of investigation, evaluation, and remediation. Based on current estimated plans, Ameren and Ameren Illinois could substantially conclude remediation efforts at most of these sites by 2015. The ICC permits Ameren Illinois to recover remediation and litigation costs associated with its former MGP sites from its electric and natural gas utility customers through environmental adjustment rate riders. To be recoverable, such costs must be prudently and properly incurred. Costs are subject to annual review by the ICC.

As of December 31, 2011, Ameren and Ameren Missouri own or are otherwise responsible for 10 MGP sites in Missouri and one site in Iowa. Ameren Missouri does not currently have a rate rider mechanism that permits recovery of remediation costs associated with MGP sites from utility customers. Ameren Missouri does not have any retail utility operations in Iowa that would provide a source of recovery of these remediation costs.

The following table presents, as of December 31, 2011, the estimated probable obligation to remediate these MGP sites.

	Estimate				Recorded Liability(a)
	Low		High
Ameren	$	107	$	183	$	107
Ameren Missouri		3		4		3
Ameren Illinois		104		179		104

(a) Recorded liability represents the estimated minimum probable obligations, as no other amount within the range provided a better estimate.

Ameren Illinois is responsible for the cleanup of a former coal ash landfill in Coffeen, Illinois. As of December 31, 2011, Ameren Illinois estimated that obligation at $0.5 million to $6 million. Ameren Illinois recorded a liability of $0.5 million to represent its estimated minimum obligation for this site, as no other amount within the range was a better estimate. Ameren Illinois is also responsible for the cleanup of a landfill, underground storage tanks, and a water treatment plant in Illinois. As of December 31, 2011, Ameren Illinois recorded a liability of $0.8 million to represent its best estimate of the obligation for these sites.

Ameren Missouri has responsibility for the investigation and potential cleanup of two waste sites in Missouri as a result of federal agency mandates. One of the cleanup sites is a former coal tar distillery located in St. Louis, Missouri. In 2008, the EPA issued an administrative order to Ameren Missouri pertaining to this distillery operated by Koppers Company or its predecessor and successor companies. Ameren Missouri is the current owner of the site, but Ameren Missouri did not conduct any of the manufacturing operations involving coal tar or its byproducts. Ameren Missouri, along with two other PRPs, is currently performing a site investigation. As of December 31, 2011, Ameren Missouri estimated its obligation at $2 million to $5 million. Ameren Missouri has a liability of $2 million recorded to represent its estimated minimum obligation, as no other amount within the range was a better estimate. Ameren Missouri's other active federal agency-mandated cleanup site in Missouri is a site in Cape Girardeau. Ameren Missouri was a customer of an electrical equipment repair and disposal company that previously operated a facility at this site. A trust was established in the early 1990s by several businesses and governmental agencies to fund the cleanup of this site, which was completed in 2005. Ameren Missouri anticipates this trust fund will be sufficient to complete the remaining adjacent off-site cleanup and therefore has no recorded liability at December 31, 2011, related to this site.

Ameren Missouri also has a federal agency mandate to complete a site investigation for a site in Illinois. In 2000, the EPA notified Ameren Missouri and numerous other companies, including Solutia, that former landfills and lagoons in Sauget, Illinois, may contain soil and groundwater contamination. These sites are known as Sauget Area 2. From about 1926 until 1976, Ameren Missouri operated an energy center adjacent to Sauget Area 2. Ameren Missouri currently owns a parcel of property that was once used as a landfill. Under the terms of an Administrative Order on Consent, Ameren Missouri has joined with other PRPs to evaluate the extent of potential contamination with respect to Sauget Area 2.

The Sauget Area 2 investigations overseen by the EPA have been completed. The results have been submitted to the EPA, and a record of decision is expected in 2012. Once the EPA has selected a remedy, if any, it would begin negotiations with various PRPs regarding implementation. Over the last several years, numerous other parties have joined the PRP group. In addition, Pharmacia Corporation and Monsanto Company have agreed to assume the liabilities related to Solutia's former chemical waste landfill in the Sauget Area 2. As of December 31, 2011, Ameren Missouri estimated its obligation at $0.3 million to $10 million. Ameren Missouri has a liability of $0.3 million recorded to represent its estimated minimum obligation, as no other amount within the range was a better estimate.

In December 2004, AERG submitted a plan to the Illinois EPA to address groundwater and surface water issues associated with the recycle pond, ash ponds, and reservoir at the Duck Creek energy center. In 2010, AERG closed the recycle pond system. Remediation work on the recycle pond was completed in the first quarter of 2011, and therefore no liability exists as of December 31, 2011.

Our operations or those of our predecessor companies involve the use of, disposal of, and in appropriate circumstances, the cleanup of substances regulated under environmental protection laws. We are unable to determine whether such practices will result in future environmental commitments or affect our results of operations, financial position, or liquidity.

Ash Management

There has been activity at both state and federal levels regarding additional regulation of ash pond facilities and CCR. In May 2010, the EPA announced proposed new regulations regarding the regulatory framework for the management and disposal of CCR, which could affect future disposal and handling costs at our energy centers. Those proposed regulations include two options for managing CCRs under either solid or hazardous waste regulations, but either alternative would allow for some continued beneficial uses, such as recycling of CCR without classifying it as waste. As part of its proposal, the EPA is considering alternative regulatory approaches that require coal-fired power plants either to close surface impoundments, such as ash ponds, or to retrofit such facilities with liners. Existing impoundments and landfills used for the disposal of CCR would be subject to groundwater monitoring requirements and requirements related to closure and postclosure care under the proposed regulations. Additionally, in January 2010, EPA announced its intent to develop regulations establishing financial responsibility requirements for the electric generation industry, among other industries, and it specifically discussed CCR as a reason for developing the new requirements. Ameren, Ameren Missouri and Genco are currently evaluating all of the proposed regulations to determine whether current management of CCR, including beneficial reuse, and the use of the ash ponds should be altered. Ameren, Ameren Missouri and Genco also are evaluating the potential costs associated with compliance with the proposed regulation of CCR impoundments and landfills, which could be material, if such regulations are adopted.

In addition, the Illinois EPA requested that Ameren, Ameren Missouri and Genco establish groundwater monitoring plans for their ash impoundments in Illinois. Ameren and the Illinois EPA have established a framework for closure of ash ponds in Illinois, including the ash ponds at Venice, Hutsonville, and Duck Creek, when such facilities are ultimately taken out of service. Ameren, Ameren Missouri and Genco have recorded AROs, based on current laws, for the estimated costs of the retirement of their ash ponds.

Pumped-storage Hydroelectric Facility Breach

In December 2005, there was a breach of the upper reservoir at Ameren Missouri's Taum Sauk pumped-storage hydroelectric energy center. This resulted in significant flooding in the local area, which damaged a state park. Ameren Missouri settled with FERC and the state of Missouri all issues associated with the December 2005 Taum Sauk incident. The rebuilt Taum Sauk energy center became fully operational in April 2010.

Ameren Missouri included certain capitalized costs associated with enhancements, or costs that would have been incurred absent the breach, at the rebuilt Taum Sauk energy center not recovered from property insurers in its 2010 electric rate case filing. However, in the July 2011 rate order, the MoPSC disallowed all of these capitalized costs associated with the rebuilding of the Taum Sauk energy center. As a result of the order, Ameren and Ameren Missouri each recorded a pretax charge to earnings in 2011 of $89 million to reflect this disallowance. See Note 2 – Rate and Regulatory Matters for additional information about the appeal of the MoPSC's July 2011 electric rate order.

Ameren Missouri had property and liability insurance coverage for the Taum Sauk incident, subject to certain limits and deductibles. Insurance did not cover some lost electric margins or penalties paid to FERC. Ameren Missouri believes that the total cost for cleanup, damage and liabilities, excluding costs to rebuild the upper reservoir, is $209 million, which is the amount Ameren Missouri had paid as of December 31, 2011. As of December 31, 2011, Ameren Missouri had recorded expenses of $37 million, primarily in prior years (2011 – $1 million, 2010 – $1 million, 2009 – $2 million), for items not covered by insurance. Ameren Missouri recorded a $172 million receivable for amounts recoverable from insurance companies under liability coverage. As of December 31, 2011, Ameren Missouri had received $104 million from insurance companies for liability claims, which reduced the insurance receivable balance subject to liability coverage to $68 million.

In June 2010, Ameren Missouri sued an insurance company that was providing Ameren Missouri with liability coverage on the date of the Taum Sauk incident. In the litigation, filed in the United States District Court for the Eastern District of Missouri, Ameren Missouri claimed the insurance company breached its duty to indemnify Ameren Missouri for the losses experienced from the incident. In January 2011, the court ruled that the parties must first pursue alternative dispute resolution under the terms of their coverage agreement. In February 2011, Ameren Missouri filed an appeal of the January ruling with the United States Court of Appeals for the Eighth Circuit, seeking the ability to pursue resolution of this dispute outside of a dispute resolution process under the terms of its coverage agreement.

Until Ameren's remaining liability insurance claims and the related litigation are resolved, we are unable to determine the total impact the breach could have on Ameren's and Ameren Missouri's results of operations, financial position, and liquidity beyond those amounts already recognized.

Asbestos-related Litigation

Ameren, Ameren Missouri, Ameren Illinois and EEI have been named, along with numerous other parties, in a number of lawsuits filed by plaintiffs claiming varying degrees of injury from asbestos exposure. Most have been filed in the Circuit Court of Madison County, Illinois. The total number of defendants named in each case varies, with as many as 272 parties named in some pending cases and as few as two in others. In the cases pending as of December 31, 2011, the average number of parties was 80.

The claims filed against Ameren, Ameren Missouri, Ameren Illinois and Genco allege injury from asbestos exposure during the plaintiffs' activities at our present or former electric generating plants. Former CIPS plants are now owned by Genco, and former CILCO plants are now owned by AERG. As a part of the transfer of ownership of the CIPS and CILCO generating plants, CIPS and CILCO, now Ameren Illinois, contractually agreed to indemnify Genco and AERG, for liabilities associated with asbestos-related claims arising from activities prior to the transfer. Each lawsuit seeks unspecified damages that, if awarded at trial, typically would be shared among the various defendants.

The following table presents the pending asbestos-related lawsuits filed against the Ameren Companies as of December 31, 2011:

Ameren	Ameren Missouri	Ameren Illinois	Genco	Total(a)
4	53	77	(b)	93

(a) Total does not equal the sum of the subsidiary unit lawsuits because some of the lawsuits name multiple Ameren entities as defendants.

(b) As of December 31, 2011, six asbestos-related lawsuits were pending against EEI. The general liability insurance maintained by EEI provides coverage with respect to liabilities arising from asbestos-related claims.

At December 31, 2011, Ameren, Ameren Missouri, Ameren Illinois and Genco had liabilities of $18 million, $6 million, $12 million, and $- million, respectively, recorded to represent their best estimate of their obligations related to asbestos claims.

Ameren Illinois has a tariff rider to recover the costs of asbestos-related litigation claims, subject to the following terms: 90% of cash expenditures in excess of the amount included in base electric rates are to be recovered from a trust fund that was established when Ameren acquired IP. At December 31, 2011, the trust fund balance was $23 million, including accumulated interest. If cash expenditures are less than the amount in base rates, Ameren Illinois will contribute 90% of the difference to the fund. Once the trust fund is depleted, 90% of allowed cash expenditures in excess of base rates will be recovered through charges assessed to customers under the tariff rider. Following the Ameren Illinois Merger, this rider is applicable only for claims that occurred within IP's historical service territory. Similarly, the rider will permit recovery only from customers within IP's historical service territory.

Illinois Sales and Use Tax Exemptions and Credits

In Exelon Corporation v. Department of Revenue, the Illinois Supreme Court decided in 2009 that electricity is tangible personal property for purposes of the Illinois income tax investment credit. In March 2010, the United States Supreme Court refused to hear the case, and the decision became final. During the second quarter of 2010, Genco and AERG began claiming Illinois sales and use tax exemptions and credits for purchase transactions related to their generation operations. The basis for those claims is that the determination in the Exelon case that electricity is tangible personal property applies to sales and use tax manufacturing exemptions and credits. On November 2, 2011, EEI received a notice of proposed tax liability, documenting the state of Illinois' position that EEI did not qualify for the manufacturing exemption it used during 2010. Genco is challenging the State of Illinois' position. In December 2011, EEI filed a request for review by the Informal Conference Board of the Illinois Department of Revenue. Ameren and Genco do not believe that it is probable that the state of Illinois will prevail and therefore have not recorded a charge to earnings for the loss contingency. From the second quarter of 2010 through December 31, 2011, Ameren and Genco claimed manufacturing exemptions and credits of $27 million and $19 million, respectively.

Ameren Energy Generating Company [Member]

Commitments And Contingencies

NOTE 15 – COMMITMENTS AND CONTINGENCIES

We are involved in legal, tax and regulatory proceedings before various courts, regulatory commissions, and governmental agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in these notes to our financial statements, will not have a material adverse effect on our results of operations, financial position, or liquidity.

See also Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 10 – Callaway Energy Center and Note 14 – Related Party Transactions in this report.

Callaway Energy Center

The following table presents insurance coverage at Ameren Missouri's Callaway energy center at December 31, 2011. The property coverage and the nuclear liability coverage must be renewed on April 1 and January 1, respectively, of each year.

Type and Source of Coverage	Maximum Coverages			Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers	$	375			$        -
Pool participation		12,219	(a)		118	(b)
	$	12,594	(c)		$   118
Property damage:
Nuclear Electric Insurance Ltd.	$	2,750	(d)		$     23
Replacement power:
Nuclear Electric Insurance Ltd	$	490	(e)		$       9
Energy Risk Assurance Company	$	64	(f)		$        -

(a) Provided through mandatory participation in an industrywide retrospective premium assessment program.

(b) Retrospective premium under Price-Anderson. This is subject to retrospective assessment with respect to a covered loss in excess of $375 million in the event of an incident at any licensed U.S. commercial reactor, payable at $17.5 million per year.

(c) Limit of liability for each incident under the Price-Anderson liability provisions of the Atomic Energy Act of 1954, as amended. A company could be assessed up to $118 million per incident for each licensed reactor it operates with a maximum of $17.5 million per incident to be paid in a calendar year for each reactor. This limit is subject to change to account for the effects of inflation and changes in the number of licensed reactors.

(d) Provides for $500 million in property damage and decontamination, excess property insurance, and premature decommissioning coverage up to $2.25 billion for losses in excess of the $500 million primary coverage.

(e) Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. Weekly indemnity up to $4.5 million for 52 weeks, which commences after the first eight weeks of an outage, plus up to $3.6 million per week for a minimum of 71 weeks thereafter for a total not exceeding the policy limit of $490 million.

(f) Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. The coverage commences after the first 52 weeks of insurance coverage from Nuclear Electric Insurance Ltd. and is for a weekly indemnity of $900,000 for 71 weeks in excess of the $3.6 million per week set forth above. Energy Risk Assurance Company is an affiliate and has reinsured this coverage with third-party insurance companies. See Note 14 – Related Party Transactions for more information on this affiliate transaction.

The Price-Anderson Act is a federal law that limits the liability for claims from an incident involving any licensed United States commercial nuclear power facility. The limit is based on the number of licensed reactors. The limit of liability and the maximum potential annual payments are adjusted at least every five years for inflation to reflect changes in the Consumer Price Index. The five-year inflationary adjustment as prescribed by the most recent Price-Anderson Act renewal was effective October 29, 2008. Owners of a nuclear reactor cover this exposure through a combination of private insurance and mandatory participation in a financial protection pool, as established by Price-Anderson.

Losses resulting from terrorist attacks are covered under Nuclear Electric Insurance Ltd.'s policies, subject to an industrywide aggregate policy limit of $3.24 billion within a 12-month period for coverage for such terrorist acts.

If losses from a nuclear incident at the Callaway energy center exceed the limits of, or are not covered by, insurance, or if coverage is unavailable, Ameren Missouri is at risk for any uninsured losses. If a serious nuclear incident were to occur, it could have a material adverse effect on Ameren's and Ameren Missouri's results of operations, financial position, or liquidity.

Leases

We lease various facilities, office equipment, plant equipment, and rail cars under operating leases. The following table presents our lease obligations at December 31, 2011:

	Total		2012		2013		2014		2015		2016		After 5 Years
Ameren:(a)
Capital lease payments(b)	$	621	$	33	$	32	$	32	$	33	$	33	$	458
Less amount representing interest		312		28		27		27		27		27		176
Present value of minimum capital lease payments	$	309	$	5	$	5	$	5	$	6	$	6	$	282
Operating leases(c)		307		38		32		26		26		25		160
Total lease obligations	$	616	$	43	$	37	$	31	$	32	$	31	$	442
Ameren Missouri:
Capital lease payments(b)	$	621	$	33	$	32	$	32	$	33	$	33	$	458
Less amount representing interest		312		28		27		27		27		27		176
Present value of minimum capital lease payments	$	309	$	5	$	5	$	5	$	6	$	6	$	282
Operating leases(c)		134		13		12		12		12		12		73
Total lease obligations	$	443	$	18	$	17	$	17	$	18	$	18	$	355
Ameren Illinois:
Operating leases(c)	$	7	$	1	$	1	$	1	$	1	$	1	$	2
Genco:
Operating leases(c)	$	131	$	11	$	11	$	11	$	10	$	11	$	77

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

(b) See Properties under Part I, Item 2, and Note 3 – Property and Plant, Net of this report for additional information.

(c) Amounts related to certain real estate leases and railroad licenses have indefinite payment periods. Ameren's $2 million annual obligation for these items is included in the 2012 through 2016 columns. The amounts for the indefinite payments are not included in the After 5 Years column because that period is indefinite.

The following table presents total rental expense, included in operating expenses, for the years ended December 31, 2011, 2010 and 2009:

	2011		2010		2009
Ameren(a)	$	47	$	52	$	50
Ameren Missouri		29		29		30
Ameren Illinois		17		19		19
Genco		12		13		15

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

Other Obligations

To supply a portion of the fuel requirements of our generating plants, we have entered into various long-term commitments for the procurement of coal, natural gas, nuclear fuel, and methane gas. We also have entered into various long-term commitments for purchased power and natural gas for distribution. The table below presents our estimated fuel, purchased power, and other commitments at December 31, 2011. Ameren's and Ameren Missouri's coal commitments include multiyear agreements to procure ultra-low-sulfur coal and related transportation from the Powder River Basin in Wyoming. Ameren's and Ameren Missouri's purchased power obligations include a 102-MW power purchase agreement with a wind farm operator that expires in 2024. Ameren's and Ameren Illinois' purchased power obligations include the Ameren Illinois power purchase agreements entered into as part of the IPA-administered power procurement process. Included in the Other column are minimum purchase commitments under contracts for equipment, design and construction, meter reading services, and an Ameren tax credit obligation at December 31, 2011. Ameren's tax credit obligation is a $17 million note payable issued for an investment in a commercial real estate development partnership to acquire tax credits. This note payable was netted against the related investment in "Other assets" on Ameren's balance sheet at December 31, 2011, as Ameren has a legally enforceable right to offset under authoritative accounting guidance.

	Coal		Natural Gas		Nuclear Fuel		Purchased Power		Methane Gas		Other		Total
Ameren:(a)
2012	$	1,120	$	398	$	36	$	196	$	1	$	221	$	1,972
2013		792		295		37		309		3		80		1,516
2014		692		220		96		125		3		75		1,211
2015		687		116		90		51		3		52		999
2016		674		39		100		52		3		62		930
Thereafter		968		134		298		746		94		246		2,486
Total	$	4,933	$	1,202	$	657	$	1,479	$	107	$	736	$	9,114
Ameren Missouri:
2012	$	623	$	63	$	36	$	19	$	1	$	78	$	820
2013		605		48		37		19		3		50		762
2014		625		36		96		19		3		47		826
2015		614		19		90		19		3		28		773
2016		644		7		100		19		3		38		811
Thereafter		921		30		298		155		94		144		1,642
Total	$	4,032	$	203	$	657	$	250	$	107	$	385	$	5,634
Ameren Illinois:
2012	$	-	$	324	$	-	$	177	$	-	$	24	$	525
2013		-		243		-		290		-		22		555
2014		-		180		-		106		-		22		308
2015		-		94		-		32		-		24		150
2016		-		31		-		33		-		24		88
Thereafter		-		105		-		591		-		102		798
Total	$	-	$	977	$	-	$	1,229	$	-	$	218	$	2,424
Genco:
2012	$	355	$	9	$	-	$	-	$	-	$	98	$	462
2013		108		4		-		-		-		5		117
2014		40		3		-		-		-		5		48
2015		45		2		-		-		-		-		47
2016		-		-		-		-		-		-		-
Thereafter		-		-		-		-		-		-		-
Total	$	548	$	18	$	-	$	-	$	-	$	108	$	674

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

Also, as part of the 2007 Illinois Electric Settlement Agreement, Ameren Illinois entered into financial contracts with Marketing Company to lock in energy prices for 400 to 1,000 megawatts annually of their round-the-clock power requirements from 2008 to 2012. These commitments are not reflected in the above table. See Note 7 – Derivative Financial Instruments and Note 14 – Related Party Transactions for additional information.

In February 2012, a rate stability procurement for energy products and renewable energy credits was administered by the IPA for the June 2013 through May 2017 period to meet certain requirements for purchased power related to the IEIMA. Ameren Illinois contracted to purchase approximately 13 million megawatthours of energy products at an average price of approximately $31 per megawatthour. Ameren Illinois is currently reviewing the results of the renewable energy credits procurement proceeding.

Ameren Illinois has entered into an agreement to purchase approximately 15.5 billion cubic feet of synthetic natural gas annually over a 10-year period beginning in 2016 for its natural gas customers. The agreement is contingent on the counterparty reaching certain milestones during the project development and the construction of the plant that will produce the synthetic natural gas. Construction has not begun on the plant; therefore, Ameren Illinois' obligations are not yet certain at this time. The agreement was entered into pursuant to an Illinois law which became effective August 2, 2011, and provides that all contract costs for synthetic natural gas incurred by Ameren Illinois are reasonable and prudent and recoverable through the PGA and are not subject to review or disallowance by the ICC.

Environmental Matters

We are subject to various environmental laws and regulations enforced by federal, state, and local authorities. From the beginning phases of siting and development to the ongoing operation of existing or new electric generating, transmission and distribution facilities, natural gas storage, transmission and distribution facilities, our activities involve compliance with diverse environmental laws and regulations. These laws and regulations address emissions, impacts to air, land and water, noise, protected natural and cultural resources (such as wetlands, endangered species and other protected wildlife, and archeological and historical resources), and chemical and waste handling. Complex and lengthy processes are required to obtain approvals, permits, or licenses for new, existing or modified facilities. Additionally, the use and handling of various chemicals or hazardous materials (including wastes) requires release prevention plans and emergency response procedures.

In addition to existing laws and regulations, including the Illinois MPS that applies to our energy centers in Illinois, the EPA is developing numerous new environmental regulations that will have a significant impact on the electric utility industry. These regulations could be particularly burdensome for certain companies, including Ameren, Ameren Missouri and Genco, that operate coal-fired energy centers. Significant new rules proposed or promulgated since the beginning of 2010 include the regulation of greenhouse gas emissions; revised national ambient air quality standards for SO₂ and NO₂ emissions; the CSAPR, which requires further reductions of SO₂ and NO_x emissions from power plants; a regulation governing management of CCR and coal ash impoundments; the MATS, which requires reduction of emissions of mercury, toxic metals, and acid gases from power plants; revised NSPS for particulate matter, SO₂, and NO_x emissions from new sources; and new regulations under the Clean Water Act that could require significant capital expenditures such as new water intake structures or cooling towers at our energy centers. The EPA also plans to propose an additional rule, applicable to new and existing electric generating units, governing NSPS and emission guidelines for greenhouse gas emissions. These new regulations may be litigated, so the timing of their implementation is uncertain, as evidenced by the stay of the CSAPR by the United States Court of Appeals for the District of Columbia on December 30, 2011. Although many details of these future regulations are unknown, the combined effects of the new and proposed environmental regulations may result in significant capital expenditures and/or increased operating costs over the next five to ten years for Ameren, Ameren Missouri and Genco. Actions required to ensure that our facilities and operations are in compliance with environmental laws and regulations could be prohibitively expensive. If they are, these regulations could require us to close or to significantly alter the operation of our energy centers, which could have an adverse effect on our results of operations, financial position, and liquidity, including the impairment of plant assets. Failure to comply with environmental laws and regulations might also result in the imposition of fines, penalties, and injunctive measures.

The estimates in the table below contain all of the known capital costs to comply with existing environmental regulations and our assessment of the potential impacts of the EPA's proposed regulation for CCR, the recently finalized MATS, the stayed CSAPR as currently designed, and the revised national ambient air quality standards for SO₂ and NO_x emissions as of December 31, 2011. The estimates in the table below assume that CCR will continue to be regarded as nonhazardous. The estimates in the table below do not include the impacts of new regulations proposed by the EPA under the Clean Water Act in March 2011 regarding cooling water intake structures as our evaluation of those impacts is ongoing. The estimates shown in the table below could change significantly depending upon a variety of factors including:

Ÿ additional federal or state requirements;

Ÿ regulation of greenhouse gas emissions;

Ÿ new national ambient air quality standards or changes to existing standards for ozone, fine particulates, SO₂, and NO_x emissions;

Ÿ additional rules governing air pollutant transport;

Ÿ finalized regulations under the Clean Water Act;

Ÿ CCR being classified as hazardous;

Ÿ whether the CSAPR is implemented and whether any modifications are made to its existing requirements;

Ÿ new technology;

Ÿ expected power prices;

Ÿ variations in costs of material or labor; and

Ÿ alternative compliance strategies or investment decisions.

	2012		2013 - 2016				2017 - 2021				Total
AMO(a)	$	55	$	325 -	$	400	$	845 -	$	1,030	$	1,225 -	$	1,485
Genco		150		100 -		125		245 -		295		495 -		570
AERG		5		20 -		25		80 -		100		105 -		130
Ameren	$	210	$	445 -	$	550	$	1,170 -	$	1,425	$	1,825 -	$	2,185

(a) Ameren Missouri's expenditures are expected to be recoverable from ratepayers.

The decision to make pollution control equipment investments at our Merchant Generation business depends on whether the expected future market price for power reflects the increased cost for environmental compliance. In early 2012, there has been a decline in the market price for wholesale power because of factors such as declining natural gas prices and the stay of the CSAPR. As a result of this decline in the market price for power, as well as uncertain environmental regulations, Genco is decelerating the construction of two scrubbers at of its Newton energy center. These scrubbers were originally expected to be installed in late 2013 and spring 2014. The ultimate installation of these scrubbers, now estimated to occur between 2017 and 2021 in the table above, has been postponed until such time as the incremental investment necessary for completion is justified by visible market conditions. However, Genco will continue to incur capital costs related to the construction of these scrubbers. The table above includes Genco's estimated costs of approximately $150 million in 2012 and approximately $20 million annually, excluding capitalized interest, from 2013 through 2016 for the construction of the two scrubbers. In addition to Genco's reduction in estimated capital expenditures, AERG is deferring precipitator upgrades at its E.D. Edwards energy center beyond 2016.

The following sections describe the more significant environmental rules that affect our operations.

Clean Air Act

Both federal and state laws require significant reductions in SO₂ and NO_x emissions that result from burning fossil fuels. In March 2005, the EPA issued regulations with respect to SO₂ and NO_x emissions (the CAIR). The CAIR required generating facilities in 28 states, including Missouri and Illinois, and the District of Columbia to participate in cap-and-trade programs to reduce annual SO₂ emissions, annual NO_x emissions, and ozone season NO_x emissions.

In December 2008, the United States Court of Appeals for the District of Columbia remanded the CAIR to the EPA for further action to remedy the rule's flaws, but allowed the CAIR's cap-and-trade programs to remain effective until they are replaced by the EPA. In July 2011, the EPA issued the CSAPR as the CAIR replacement. The CSAPR was to become effective on January 1, 2012, for SO₂ and annual NO_x reductions and on May 1, 2012, for ozone season NO_x reductions. In the CSAPR, the EPA developed federal implementation plans for each state covered by this rule; however, each impacted state can develop its own implementation rule starting as early as 2013. The CSAPR establishes emission allowance budgets for each of the states subject to the regulation, including Missouri and Illinois. With the CSAPR, the EPA abandoned CAIR's regional approach to cutting emissions and instead set a pollution budget for each of the impacted states based on the EPA's analysis of each upwind state's contribution to air quality in downwind states. For Missouri and Illinois, emission reductions were required in two phases beginning in 2012, with further reductions in 2014. With the CSAPR, the EPA adopted a cap-and-trade approach that allows intrastate and limited interstate trading of emission allowances with other sources within the same program, that is, in the SO₂ program, in the annual NO_x, or in ozone season NO_x program. Multiple legal challenges were filed requesting to have CSAPR partially or entirely vacated and to stay the implementation of the CSAPR while the court considers the challenges. On December 30, 2011, the United States Court of Appeals for the District of Columbia issued a stay of the CSAPR. The stay does not invalidate the rule, but only delays its implementation until a final court ruling is issued. The United States Court of Appeals for the District of Columbia has expedited its consideration of the regulation and will hear arguments on the validity of CSAPR in April 2012. The ultimate outcome of the challenges to the regulation is uncertain. The court could uphold CSAPR or remand it back to the EPA for partial or entire revision. Until the CSAPR appeal process is concluded, the EPA will continue to administer the CAIR.

On December 21, 2011, the EPA issued the final MATS under the Clean Air Act, which require emission reductions for mercury and other hazardous air pollutants, such as acid gases, toxic metals, and particulate matter by setting emission limits equal to the average emissions of the best performing 12% of existing coal and oil-fired electric generating units. Also, the rule requires reductions in hydrogen chloride emissions, which were not regulated previously, and it may require continuous monitoring systems that are not currently in place. The MATS do not require a specific control technology to achieve the emission reductions. The MATS will apply to each unit at a coal-fired power plant; however, emission compliance can be averaged for the entire power plant. Compliance is required by April 2015 or, with a case-by-case extension, by April 2016.

Separately, in January and June 2010, the EPA finalized new ambient air quality standards for SO₂ and NO₂. It also announced plans for further reductions in the annual national ambient air quality standards for ozone and fine particulates. The state of Illinois and the state of Missouri will be required to develop separate attainment plans to comply with the new ambient air quality standards. Ameren, Ameren Missouri and Genco continue to assess the impacts of these new standards. In September 2011, the EPA withdrew its draft annual national ambient air quality standard for ozone and announced that it was implementing the 2008 national ambient air quality standard for ozone. The EPA is required to revisit this standard again in 2013.

Ameren Missouri's current environmental compliance plan for air emissions from its energy centers includes burning ultra-low-sulfur coal and installing new or optimizing existing pollution control equipment. In July 2011, Ameren Missouri contracted to procure significantly higher volumes of lower-sulfur-content coal than Ameren Missouri's energy centers have historically burned, which will allow Ameren Missouri to eliminate or postpone capital expenditures for pollution control equipment while still achieving required emissions levels. In 2010, Ameren Missouri completed the installation of two scrubbers at its Sioux energy center to reduce SO₂ emissions. Currently, Ameren Missouri's compliance plan assumes the installation of two scrubbers within its coal-fired fleet during the next 10 years and precipitator upgrades at multiple energy centers. However, Ameren Missouri is currently evaluating its operations and options to determine how to comply with the additional emission reductions requirements in 2014 set forth in the CSAPR, if ultimately enacted, the MATS, and other recently finalized or proposed EPA regulations.

Existing Illinois state regulations already required Ameren and Genco to reduce their emissions of mercury under the MPS. Ameren's and Genco's review of the MATS indicates that the scope of the federal standards is broader than the MPS, as no exemption exists for smaller coal-fired plants. Additionally, the MATS are more stringent than the MPS because compliance with the MATS is measured on a quarterly basis and, in some cases, a thirty-day rolling basis and not annually, as allowed under state requirements. At the end of 2011, Genco ceased operations of its Meredosia and Hutsonville energy centers. The closure of these energy centers was primarily due to the expected cost of complying with CSAPR and MATS. See Note 17 – Goodwill, Impairment and Other Charges for additional information.

Genco and AERG expect to install additional, or optimize existing, pollution control equipment, or modify operations to meet new and incremental emission reduction requirements under the MPS, the MATS, or the CSAPR as they become effective. Under the MPS, as amended, Illinois generators are required to reduce mercury, SO₂, and NO_x emissions by 2015. To comply with the MPS and other air emissions laws and regulations, Genco and AERG are installing equipment designed to reduce their emissions of mercury, NO_x, and SO₂. Genco and AERG have installed a total of three scrubbers at two energy centers. Two additional scrubbers are being constructed at Genco's Newton energy center. As discussed above, the timing of the installation of these scrubbers as well as precipitator upgrades at AERG's E.D. Edwards energy center have been extended. The closure of Genco's Meredosia and Hutsonville energy centers will allow the Merchant Generation segment additional flexibility in the methods to achieve compliance with environmental standards. Merchant Generation and Genco will continue to review and adjust their compliance plans in light of evolving outlooks for power and capacity prices, delivered fuel costs, environment standards and compliance technologies, among other factors.

The completion of Ameren's, Ameren Missouri's and Genco's review of recently finalized environmental regulations and compliance measures could result in significant increases in capital expenditures and operating costs. The compliance costs could be prohibitive at some of our energy centers as the expected return from these investments, at current market prices for energy and capacity, might not justify the required capital expenditures or their continued operation, which could result in the impairment of long-lived assets.

Emission Allowances

The Clean Air Act created marketable commodities called allowances under the acid rain program, the NO_x budget trading program, the CAIR, and the CSAPR. With the CSAPR, the EPA adopted a cap-and-trade approach that allows intrastate and limited interstate trading of emission allowances with other sources within the same program, that is, either the SO₂, annual NO_x, or ozone season NO_x programs. As noted above, on December 30, 2011, the United States Court of Appeals for the District of Columbia issued a stay of the CSAPR. Until the CSAPR appeal process is concluded, the EPA will continue to administer the CAIR including its allowance program. See Note 1 – Summary of Significant Accounting Policies for the SO₂ and NO_x emission allowance book values that were classified as intangible assets as of December 31, 2011 and 2010, and Note 17 – Goodwill, Impairment and Other Charges for information regarding the emission allowance impairments recorded during 2011 and 2010.

Environmental regulations including the CAIR and the CSAPR, the timing of the installation of pollution control equipment, fuel mix, and the level of operations, will have a significant impact on the number of allowances required for ongoing operations. The CAIR uses the acid rain program's allowances for SO₂ emissions and created annual and ozone season NO_x allowances. The CSAPR, however, will not rely upon the acid rain program, the NO_x budget trading program, or CAIR allowances for its allowance allocation program. Instead, the EPA issued a new type of emissions allowance for each program under the CSAPR. Any unused SO₂ allowances, annual NO_x allowances, and ozone season NO_x allowances issued under CAIR cannot be used for compliance with CSAPR. Ameren, Ameren Missouri and Genco expect to have adequate CAIR allowances for 2012 to avoid needing to make external purchases.

Should the CSAPR become effective as issued, Ameren, Ameren Missouri and Genco are studying their compliance options to identify additional opportunities that may exist for compliance in an economical fashion. Ameren, Ameren Missouri and Genco may be required to purchase emission allowances, if available, to install new or optimize existing pollution control equipment, to limit generation, or take other actions to achieve compliance with the CSAPR in future phase-in years.

Global Climate Change

State and federal authorities, including the United States Congress, have considered initiatives to limit greenhouse gas emissions and to address global climate change. Potential impacts from any climate change legislation or regulation could vary, depending upon proposed CO₂ emission limits, the timing of implementation of those limits, the method of distributing any allowances, the degree to which offsets are allowed and available, and provisions for cost-containment measures, such as a "safety valve" provision that provides a maximum price for emission allowances. As a result of our diverse fuel portfolio, our emissions of greenhouse gases vary among our energy centers, but coal-fired power plants are significant sources of CO₂. The enactment of a climate change law could result in a significant rise in household costs and rates for electricity could rise significantly. The burden could fall particularly hard on electricity consumers and upon the economy in the Midwest because of the region's reliance on electricity generated by coal-fired power plants. Natural gas emits about half as much CO₂ as coal when burned to produce electricity. Therefore, climate change regulation could cause the conversion of coal-fired power plants to natural gas, or the construction of new natural gas plants to replace coal-fired power plants. As a result, economywide shifts to natural gas as a fuel source for electricity generation also could affect the cost of heating for our utility customers and many industrial processes that use natural gas.

In December 2009, the EPA issued its "endangerment finding" under the Clean Air Act which stated that greenhouse gas emissions, including CO₂, endanger human health and welfare and that emissions of greenhouse gases from motor vehicles contribute to that endangerment. In March 2010, the EPA issued a determination that greenhouse gas emissions from stationary sources, such as power plants, would be subject to regulation under the Clean Air Act effective the beginning of 2011. As a result of these actions, we are required to consider the emissions of greenhouse gases in any air permit application.

Recognizing the difficulties presented by regulating at once virtually all emitters of greenhouse gases, the EPA finalized in May 2010 regulations, known as the "Tailoring Rule," that established new higher thresholds for regulating greenhouse gas emissions from stationary sources, such as power plants. The Tailoring Rule became effective in January 2011. The rule requires any source that already has an operating permit to have greenhouse-gas-specific provisions added to its permits upon renewal. Currently, all Ameren energy centers have operating permits that, when renewed, may be modified to address greenhouse gas emissions. The Tailoring Rule also provides that if projects performed at major sources result in an increase in emissions of greenhouse gases of at least 75,000 tons per year, measured in CO₂ equivalents, such projects could trigger permitting requirements under the NSR programs and the application of best available control technology, if any, to control greenhouse gas emissions. New major sources are also required to obtain such a permit and to install the best available control technology if their greenhouse gas emissions exceed the applicable emissions threshold. Separately, in December 2010, the EPA announced a settlement agreement under which it would propose NSPS for greenhouse gas emissions at new and existing fossil fuel-fired power plants by July 26, 2011 and issue a final standard by May 2012. The EPA has not yet proposed a rule and has not specified a new estimate of when it will issue that standard. It is uncertain whether reductions to greenhouse gas emissions would be required at Ameren's, Ameren Missouri's or Genco's energy centers as a result of any of the EPA's new and future rules. Legal challenges to the EPA's greenhouse gas rules have been filed. Any federal climate change legislation that is enacted may preempt the EPA's regulation of greenhouse gas emissions, including the Tailoring Rule, particularly as it relates to power plant greenhouse gas emissions. The extent to which the Tailoring Rule could have a material impact on our energy centers depends upon how state agencies apply the EPA's guidelines as to what constitutes the best available control technology for greenhouse gas emissions from power plants and whether physical changes or changes in operations subject to the rule occur at our energy centers. Although the EPA has stated its intention to regulate greenhouse gas emissions from stationary sources, such as power plants, congressional action could block or delay that effort.

Future federal and state legislation or regulations that mandate limits on the emission of greenhouse gases would likely result in significant increases in capital expenditures and operating costs, which, in turn, could lead to increased liquidity needs and higher financing costs. Moreover, to the extent Ameren Missouri requests recovery of these costs through rates, its regulators might delay or deny timely recovery of these costs. Excessive costs to comply with future legislation or regulations might force Ameren, Ameren Missouri and Genco as well as other similarly situated electric power generators to close some coal-fired facilities earlier than planned, which could lead to possible impairment of assets and reduced revenues. As a result, mandatory limits could have a material adverse impact on Ameren's, Ameren Missouri's, and Genco's results of operations, financial position, and liquidity.

Recent federal court decisions have considered the application of common law causes of action, such as nuisance, to address damages resulting from global climate change. In June 2011, the United States Supreme Court in State of Connecticut v. American Electric Power rejected state efforts to impose liability for CO₂ and greenhouse gases emissions under federal common law. That ruling, however, did not address whether private citizens could pursue causes of action based on state common law. In June 2011, a case called Comer v. Murphy Oil (Comer) was filed in the United States District Court for the Southern District of Mississippi. In this litigation, a Mississippi property owner sued several industrial companies, including Ameren Missouri and Genco, alleging that CO₂ emissions created the atmospheric conditions that intensified Hurricane Katrina. Although we are unable to predict the outcome of the Comer litigation on our results of operations, financial position, and liquidity, Ameren believes that it has meritorious defenses. Numerous procedural and substantive challenges are expected in the Comer litigation.

The impact on us of future initiatives related to greenhouse gas emissions and global climate change is unknown. Compliance costs could increase as future federal legislative, federal regulatory, and state-sponsored initiatives to control greenhouse gases continue to progress, making it more likely that some form of greenhouse gas emissions control will eventually be required. Since these initiatives continue to evolve, the impact on our coal-fired energy centers and our customers' costs is unknown, but any impact would probably be negative. Our costs of complying with any mandated federal or state greenhouse gas program could have a material impact on our future results of operations, financial position, and liquidity.

NSR and Clean Air Litigation

The EPA is engaged in an enforcement initiative to determine whether coal-fired power plants failed to comply with the requirements of the NSR and NSPS provisions under the Clean Air Act when the plants implemented modifications. The EPA's inquiries focus on whether projects performed at power plants should have triggered various permitting requirements and the installation of pollution control equipment.

In April 2005, Genco received a request from the EPA for information pursuant to Section 114(a) of the Clean Air Act. The request sought detailed operating and maintenance history data with respect to Genco's Coffeen, Hutsonville, Meredosia, Newton, and Joppa energy centers and AERG's E.D. Edwards and Duck Creek energy centers. In 2006, the EPA issued a second Section 114(a) request to Genco regarding projects at the Newton energy center. All of these facilities are coal-fired energy centers. In September 2008, the EPA issued a third Section 114(a) request regarding projects at all of Ameren's coal-fired energy centers in Illinois. We completed our response to the information requests, but we are unable to predict the outcome of this matter.

Following the issuance of a Notice of Violation, in January 2011, the Department of Justice on behalf of the EPA filed a complaint against Ameren Missouri in the United States District Court for the Eastern District of Missouri. The EPA's complaint alleges that in performing projects at its Rush Island coal-fired energy center, Ameren Missouri violated provisions of the Clean Air Act and Missouri law. In January 2012, the United States District Court granted, in part, Ameren Missouri's motion to dismiss various aspects of the EPA's penalty claims. The EPA's claims for injunctive relief, including to require the installation of pollution control equipment, remain. At present, the complaint does not include Ameren Missouri's other coal-fired energy centers, but the EPA has issued Notices of Violation under its NSR enforcement initiative against the company's Labadie, Meramec, and Sioux coal-fired energy centers. Litigation of this matter could take many years to resolve. Ameren Missouri believes its defenses to the allegations described in the complaint as well as the Notices of Violation are meritorious. Ameren Missouri will defend itself vigorously. However, there can be no assurances that it will be successful in its efforts.

Ultimate resolution of these matters could have a material adverse impact on the future results of operations, financial position, and liquidity of Ameren, Ameren Missouri and Genco. A resolution could result in increased capital expenditures for the installation of pollution control equipment, increased operations and maintenance expenses, and penalties. We are unable to predict the ultimate resolution of these matters or the costs that might be incurred. However, Ameren Missouri has concluded that, while a loss may be reasonably possible, the likelihood of loss is not probable. Therefore, no reserve has been established.

Clean Water Act

In March 2011, the EPA announced a proposed rule applicable to cooling water intake structures at existing power plants that have the ability to withdraw more than 2 million gallons of water per day from a body of water and use at least 25 percent of that water exclusively for cooling. Under the proposed rule, affected facilities would be required either to meet mortality limits for aquatic life impinged on the plant's intake screens or to reduce intake velocity to 0.5 feet per second. The proposed rule also requires plants to meet site-specific entrainment standards or to reduce the cooling water intake flow commensurate with the intake flow of a closed-cycle cooling system. The final rule is scheduled to be issued in July 2012, with compliance expected within eight years thereafter. All coal-fired, nuclear, and combined cycle energy centers at Ameren, Ameren Missouri and Genco with cooling water systems are subject to this proposed rule. The proposed rule did not mandate cooling towers at existing facilities, as other technology options potentially could meet the site-specific standards. Ameren, Ameren Missouri and Genco are currently evaluating the proposed rule, and their assessment of the proposed rule's impacts is ongoing. Therefore, we cannot predict at this time the capital or operating costs associated with compliance. The proposed rule could have an adverse effect on our results of operations, financial position, and liquidity if its implementation requires the installation of cooling towers at our electric generating stations.

In September 2009, the EPA announced its plan to revise the effluent guidelines applicable to steam electric generating units under the Clean Water Act. Effluent guidelines are national standards for wastewater discharges to surface water that are based on the effectiveness of available control technology. The EPA is engaged in information collection and analysis activities in support of this rulemaking. It has indicated that it expects to issue a proposed rule in July 2012 and to finalize the rule in 2014. We are unable at this time to predict the impact of this development.

Remediation

We are involved in a number of remediation actions to clean up hazardous waste sites as required by federal and state law. Such statutes require that responsible parties fund remediation actions regardless of their degree of fault, the legality of original disposal, or the ownership of a disposal site. Ameren Missouri and Ameren Illinois have each been identified by the federal or state governments as a potentially responsible party (PRP) at several contaminated sites. Several of these sites involve facilities that were transferred by our rate-regulated utility operations in Illinois to Genco in May 2000 and to AERG in October 2003. As part of each transfer, Ameren Illinois contractually agreed to indemnify Genco and AERG for remediation costs associated with preexisting environmental contamination at the transferred sites.

As of December 31, 2011, Ameren and Ameren Illinois owned or were otherwise responsible for 44 former MGP sites in Illinois. These are in various stages of investigation, evaluation, and remediation. Based on current estimated plans, Ameren and Ameren Illinois could substantially conclude remediation efforts at most of these sites by 2015. The ICC permits Ameren Illinois to recover remediation and litigation costs associated with its former MGP sites from its electric and natural gas utility customers through environmental adjustment rate riders. To be recoverable, such costs must be prudently and properly incurred. Costs are subject to annual review by the ICC.

As of December 31, 2011, Ameren and Ameren Missouri own or are otherwise responsible for 10 MGP sites in Missouri and one site in Iowa. Ameren Missouri does not currently have a rate rider mechanism that permits recovery of remediation costs associated with MGP sites from utility customers. Ameren Missouri does not have any retail utility operations in Iowa that would provide a source of recovery of these remediation costs.

The following table presents, as of December 31, 2011, the estimated probable obligation to remediate these MGP sites.

	Estimate				Recorded Liability(a)
	Low		High
Ameren	$	107	$	183	$	107
Ameren Missouri		3		4		3
Ameren Illinois		104		179		104

(a) Recorded liability represents the estimated minimum probable obligations, as no other amount within the range provided a better estimate.

Ameren Illinois is responsible for the cleanup of a former coal ash landfill in Coffeen, Illinois. As of December 31, 2011, Ameren Illinois estimated that obligation at $0.5 million to $6 million. Ameren Illinois recorded a liability of $0.5 million to represent its estimated minimum obligation for this site, as no other amount within the range was a better estimate. Ameren Illinois is also responsible for the cleanup of a landfill, underground storage tanks, and a water treatment plant in Illinois. As of December 31, 2011, Ameren Illinois recorded a liability of $0.8 million to represent its best estimate of the obligation for these sites.

Ameren Missouri has responsibility for the investigation and potential cleanup of two waste sites in Missouri as a result of federal agency mandates. One of the cleanup sites is a former coal tar distillery located in St. Louis, Missouri. In 2008, the EPA issued an administrative order to Ameren Missouri pertaining to this distillery operated by Koppers Company or its predecessor and successor companies. Ameren Missouri is the current owner of the site, but Ameren Missouri did not conduct any of the manufacturing operations involving coal tar or its byproducts. Ameren Missouri, along with two other PRPs, is currently performing a site investigation. As of December 31, 2011, Ameren Missouri estimated its obligation at $2 million to $5 million. Ameren Missouri has a liability of $2 million recorded to represent its estimated minimum obligation, as no other amount within the range was a better estimate. Ameren Missouri's other active federal agency-mandated cleanup site in Missouri is a site in Cape Girardeau. Ameren Missouri was a customer of an electrical equipment repair and disposal company that previously operated a facility at this site. A trust was established in the early 1990s by several businesses and governmental agencies to fund the cleanup of this site, which was completed in 2005. Ameren Missouri anticipates this trust fund will be sufficient to complete the remaining adjacent off-site cleanup and therefore has no recorded liability at December 31, 2011, related to this site.

Ameren Missouri also has a federal agency mandate to complete a site investigation for a site in Illinois. In 2000, the EPA notified Ameren Missouri and numerous other companies, including Solutia, that former landfills and lagoons in Sauget, Illinois, may contain soil and groundwater contamination. These sites are known as Sauget Area 2. From about 1926 until 1976, Ameren Missouri operated an energy center adjacent to Sauget Area 2. Ameren Missouri currently owns a parcel of property that was once used as a landfill. Under the terms of an Administrative Order on Consent, Ameren Missouri has joined with other PRPs to evaluate the extent of potential contamination with respect to Sauget Area 2.

The Sauget Area 2 investigations overseen by the EPA have been completed. The results have been submitted to the EPA, and a record of decision is expected in 2012. Once the EPA has selected a remedy, if any, it would begin negotiations with various PRPs regarding implementation. Over the last several years, numerous other parties have joined the PRP group. In addition, Pharmacia Corporation and Monsanto Company have agreed to assume the liabilities related to Solutia's former chemical waste landfill in the Sauget Area 2. As of December 31, 2011, Ameren Missouri estimated its obligation at $0.3 million to $10 million. Ameren Missouri has a liability of $0.3 million recorded to represent its estimated minimum obligation, as no other amount within the range was a better estimate.

In December 2004, AERG submitted a plan to the Illinois EPA to address groundwater and surface water issues associated with the recycle pond, ash ponds, and reservoir at the Duck Creek energy center. In 2010, AERG closed the recycle pond system. Remediation work on the recycle pond was completed in the first quarter of 2011, and therefore no liability exists as of December 31, 2011.

Our operations or those of our predecessor companies involve the use of, disposal of, and in appropriate circumstances, the cleanup of substances regulated under environmental protection laws. We are unable to determine whether such practices will result in future environmental commitments or affect our results of operations, financial position, or liquidity.

Ash Management

There has been activity at both state and federal levels regarding additional regulation of ash pond facilities and CCR. In May 2010, the EPA announced proposed new regulations regarding the regulatory framework for the management and disposal of CCR, which could affect future disposal and handling costs at our energy centers. Those proposed regulations include two options for managing CCRs under either solid or hazardous waste regulations, but either alternative would allow for some continued beneficial uses, such as recycling of CCR without classifying it as waste. As part of its proposal, the EPA is considering alternative regulatory approaches that require coal-fired power plants either to close surface impoundments, such as ash ponds, or to retrofit such facilities with liners. Existing impoundments and landfills used for the disposal of CCR would be subject to groundwater monitoring requirements and requirements related to closure and postclosure care under the proposed regulations. Additionally, in January 2010, EPA announced its intent to develop regulations establishing financial responsibility requirements for the electric generation industry, among other industries, and it specifically discussed CCR as a reason for developing the new requirements. Ameren, Ameren Missouri and Genco are currently evaluating all of the proposed regulations to determine whether current management of CCR, including beneficial reuse, and the use of the ash ponds should be altered. Ameren, Ameren Missouri and Genco also are evaluating the potential costs associated with compliance with the proposed regulation of CCR impoundments and landfills, which could be material, if such regulations are adopted.

In addition, the Illinois EPA requested that Ameren, Ameren Missouri and Genco establish groundwater monitoring plans for their ash impoundments in Illinois. Ameren and the Illinois EPA have established a framework for closure of ash ponds in Illinois, including the ash ponds at Venice, Hutsonville, and Duck Creek, when such facilities are ultimately taken out of service. Ameren, Ameren Missouri and Genco have recorded AROs, based on current laws, for the estimated costs of the retirement of their ash ponds.

Pumped-storage Hydroelectric Facility Breach

In December 2005, there was a breach of the upper reservoir at Ameren Missouri's Taum Sauk pumped-storage hydroelectric energy center. This resulted in significant flooding in the local area, which damaged a state park. Ameren Missouri settled with FERC and the state of Missouri all issues associated with the December 2005 Taum Sauk incident. The rebuilt Taum Sauk energy center became fully operational in April 2010.

Ameren Missouri included certain capitalized costs associated with enhancements, or costs that would have been incurred absent the breach, at the rebuilt Taum Sauk energy center not recovered from property insurers in its 2010 electric rate case filing. However, in the July 2011 rate order, the MoPSC disallowed all of these capitalized costs associated with the rebuilding of the Taum Sauk energy center. As a result of the order, Ameren and Ameren Missouri each recorded a pretax charge to earnings in 2011 of $89 million to reflect this disallowance. See Note 2 – Rate and Regulatory Matters for additional information about the appeal of the MoPSC's July 2011 electric rate order.

Ameren Missouri had property and liability insurance coverage for the Taum Sauk incident, subject to certain limits and deductibles. Insurance did not cover some lost electric margins or penalties paid to FERC. Ameren Missouri believes that the total cost for cleanup, damage and liabilities, excluding costs to rebuild the upper reservoir, is $209 million, which is the amount Ameren Missouri had paid as of December 31, 2011. As of December 31, 2011, Ameren Missouri had recorded expenses of $37 million, primarily in prior years (2011 – $1 million, 2010 – $1 million, 2009 – $2 million), for items not covered by insurance. Ameren Missouri recorded a $172 million receivable for amounts recoverable from insurance companies under liability coverage. As of December 31, 2011, Ameren Missouri had received $104 million from insurance companies for liability claims, which reduced the insurance receivable balance subject to liability coverage to $68 million.

In June 2010, Ameren Missouri sued an insurance company that was providing Ameren Missouri with liability coverage on the date of the Taum Sauk incident. In the litigation, filed in the United States District Court for the Eastern District of Missouri, Ameren Missouri claimed the insurance company breached its duty to indemnify Ameren Missouri for the losses experienced from the incident. In January 2011, the court ruled that the parties must first pursue alternative dispute resolution under the terms of their coverage agreement. In February 2011, Ameren Missouri filed an appeal of the January ruling with the United States Court of Appeals for the Eighth Circuit, seeking the ability to pursue resolution of this dispute outside of a dispute resolution process under the terms of its coverage agreement.

Until Ameren's remaining liability insurance claims and the related litigation are resolved, we are unable to determine the total impact the breach could have on Ameren's and Ameren Missouri's results of operations, financial position, and liquidity beyond those amounts already recognized.

Asbestos-related Litigation

Ameren, Ameren Missouri, Ameren Illinois and EEI have been named, along with numerous other parties, in a number of lawsuits filed by plaintiffs claiming varying degrees of injury from asbestos exposure. Most have been filed in the Circuit Court of Madison County, Illinois. The total number of defendants named in each case varies, with as many as 272 parties named in some pending cases and as few as two in others. In the cases pending as of December 31, 2011, the average number of parties was 80.

The claims filed against Ameren, Ameren Missouri, Ameren Illinois and Genco allege injury from asbestos exposure during the plaintiffs' activities at our present or former electric generating plants. Former CIPS plants are now owned by Genco, and former CILCO plants are now owned by AERG. As a part of the transfer of ownership of the CIPS and CILCO generating plants, CIPS and CILCO, now Ameren Illinois, contractually agreed to indemnify Genco and AERG, for liabilities associated with asbestos-related claims arising from activities prior to the transfer. Each lawsuit seeks unspecified damages that, if awarded at trial, typically would be shared among the various defendants.

The following table presents the pending asbestos-related lawsuits filed against the Ameren Companies as of December 31, 2011:

Ameren	Ameren Missouri	Ameren Illinois	Genco	Total(a)
4	53	77	(b)	93

(a) Total does not equal the sum of the subsidiary unit lawsuits because some of the lawsuits name multiple Ameren entities as defendants.

(b) As of December 31, 2011, six asbestos-related lawsuits were pending against EEI. The general liability insurance maintained by EEI provides coverage with respect to liabilities arising from asbestos-related claims.

At December 31, 2011, Ameren, Ameren Missouri, Ameren Illinois and Genco had liabilities of $18 million, $6 million, $12 million, and $- million, respectively, recorded to represent their best estimate of their obligations related to asbestos claims.

Ameren Illinois has a tariff rider to recover the costs of asbestos-related litigation claims, subject to the following terms: 90% of cash expenditures in excess of the amount included in base electric rates are to be recovered from a trust fund that was established when Ameren acquired IP. At December 31, 2011, the trust fund balance was $23 million, including accumulated interest. If cash expenditures are less than the amount in base rates, Ameren Illinois will contribute 90% of the difference to the fund. Once the trust fund is depleted, 90% of allowed cash expenditures in excess of base rates will be recovered through charges assessed to customers under the tariff rider. Following the Ameren Illinois Merger, this rider is applicable only for claims that occurred within IP's historical service territory. Similarly, the rider will permit recovery only from customers within IP's historical service territory.

Illinois Sales and Use Tax Exemptions and Credits

In Exelon Corporation v. Department of Revenue, the Illinois Supreme Court decided in 2009 that electricity is tangible personal property for purposes of the Illinois income tax investment credit. In March 2010, the United States Supreme Court refused to hear the case, and the decision became final. During the second quarter of 2010, Genco and AERG began claiming Illinois sales and use tax exemptions and credits for purchase transactions related to their generation operations. The basis for those claims is that the determination in the Exelon case that electricity is tangible personal property applies to sales and use tax manufacturing exemptions and credits. On November 2, 2011, EEI received a notice of proposed tax liability, documenting the state of Illinois' position that EEI did not qualify for the manufacturing exemption it used during 2010. Genco is challenging the State of Illinois' position. In December 2011, EEI filed a request for review by the Informal Conference Board of the Illinois Department of Revenue. Ameren and Genco do not believe that it is probable that the state of Illinois will prevail and therefore have not recorded a charge to earnings for the loss contingency. From the second quarter of 2010 through December 31, 2011, Ameren and Genco claimed manufacturing exemptions and credits of $27 million and $19 million, respectively.

Union Electric Company [Member]

Commitments And Contingencies

NOTE 15 – COMMITMENTS AND CONTINGENCIES

We are involved in legal, tax and regulatory proceedings before various courts, regulatory commissions, and governmental agencies with respect to matters that arise in the ordinary course of business, some of which involve substantial amounts of money. We believe that the final disposition of these proceedings, except as otherwise disclosed in these notes to our financial statements, will not have a material adverse effect on our results of operations, financial position, or liquidity.

See also Note 1 – Summary of Significant Accounting Policies, Note 2 – Rate and Regulatory Matters, Note 10 – Callaway Energy Center and Note 14 – Related Party Transactions in this report.

Callaway Energy Center

The following table presents insurance coverage at Ameren Missouri's Callaway energy center at December 31, 2011. The property coverage and the nuclear liability coverage must be renewed on April 1 and January 1, respectively, of each year.

Type and Source of Coverage	Maximum Coverages			Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers	$	375			$        -
Pool participation		12,219	(a)		118	(b)
	$	12,594	(c)		$   118
Property damage:
Nuclear Electric Insurance Ltd.	$	2,750	(d)		$     23
Replacement power:
Nuclear Electric Insurance Ltd	$	490	(e)		$       9
Energy Risk Assurance Company	$	64	(f)		$        -

(a) Provided through mandatory participation in an industrywide retrospective premium assessment program.

(b) Retrospective premium under Price-Anderson. This is subject to retrospective assessment with respect to a covered loss in excess of $375 million in the event of an incident at any licensed U.S. commercial reactor, payable at $17.5 million per year.

(c) Limit of liability for each incident under the Price-Anderson liability provisions of the Atomic Energy Act of 1954, as amended. A company could be assessed up to $118 million per incident for each licensed reactor it operates with a maximum of $17.5 million per incident to be paid in a calendar year for each reactor. This limit is subject to change to account for the effects of inflation and changes in the number of licensed reactors.

(d) Provides for $500 million in property damage and decontamination, excess property insurance, and premature decommissioning coverage up to $2.25 billion for losses in excess of the $500 million primary coverage.

(e) Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. Weekly indemnity up to $4.5 million for 52 weeks, which commences after the first eight weeks of an outage, plus up to $3.6 million per week for a minimum of 71 weeks thereafter for a total not exceeding the policy limit of $490 million.

(f) Provides the replacement power cost insurance in the event of a prolonged accidental outage at our nuclear energy center. The coverage commences after the first 52 weeks of insurance coverage from Nuclear Electric Insurance Ltd. and is for a weekly indemnity of $900,000 for 71 weeks in excess of the $3.6 million per week set forth above. Energy Risk Assurance Company is an affiliate and has reinsured this coverage with third-party insurance companies. See Note 14 – Related Party Transactions for more information on this affiliate transaction.

The Price-Anderson Act is a federal law that limits the liability for claims from an incident involving any licensed United States commercial nuclear power facility. The limit is based on the number of licensed reactors. The limit of liability and the maximum potential annual payments are adjusted at least every five years for inflation to reflect changes in the Consumer Price Index. The five-year inflationary adjustment as prescribed by the most recent Price-Anderson Act renewal was effective October 29, 2008. Owners of a nuclear reactor cover this exposure through a combination of private insurance and mandatory participation in a financial protection pool, as established by Price-Anderson.

Losses resulting from terrorist attacks are covered under Nuclear Electric Insurance Ltd.'s policies, subject to an industrywide aggregate policy limit of $3.24 billion within a 12-month period for coverage for such terrorist acts.

If losses from a nuclear incident at the Callaway energy center exceed the limits of, or are not covered by, insurance, or if coverage is unavailable, Ameren Missouri is at risk for any uninsured losses. If a serious nuclear incident were to occur, it could have a material adverse effect on Ameren's and Ameren Missouri's results of operations, financial position, or liquidity.

Leases

We lease various facilities, office equipment, plant equipment, and rail cars under operating leases. The following table presents our lease obligations at December 31, 2011:

	Total		2012		2013		2014		2015		2016		After 5 Years
Ameren:(a)
Capital lease payments(b)	$	621	$	33	$	32	$	32	$	33	$	33	$	458
Less amount representing interest		312		28		27		27		27		27		176
Present value of minimum capital lease payments	$	309	$	5	$	5	$	5	$	6	$	6	$	282
Operating leases(c)		307		38		32		26		26		25		160
Total lease obligations	$	616	$	43	$	37	$	31	$	32	$	31	$	442
Ameren Missouri:
Capital lease payments(b)	$	621	$	33	$	32	$	32	$	33	$	33	$	458
Less amount representing interest		312		28		27		27		27		27		176
Present value of minimum capital lease payments	$	309	$	5	$	5	$	5	$	6	$	6	$	282
Operating leases(c)		134		13		12		12		12		12		73
Total lease obligations	$	443	$	18	$	17	$	17	$	18	$	18	$	355
Ameren Illinois:
Operating leases(c)	$	7	$	1	$	1	$	1	$	1	$	1	$	2
Genco:
Operating leases(c)	$	131	$	11	$	11	$	11	$	10	$	11	$	77

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

(b) See Properties under Part I, Item 2, and Note 3 – Property and Plant, Net of this report for additional information.

(c) Amounts related to certain real estate leases and railroad licenses have indefinite payment periods. Ameren's $2 million annual obligation for these items is included in the 2012 through 2016 columns. The amounts for the indefinite payments are not included in the After 5 Years column because that period is indefinite.

The following table presents total rental expense, included in operating expenses, for the years ended December 31, 2011, 2010 and 2009:

	2011		2010		2009
Ameren(a)	$	47	$	52	$	50
Ameren Missouri		29		29		30
Ameren Illinois		17		19		19
Genco		12		13		15

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

Other Obligations

To supply a portion of the fuel requirements of our generating plants, we have entered into various long-term commitments for the procurement of coal, natural gas, nuclear fuel, and methane gas. We also have entered into various long-term commitments for purchased power and natural gas for distribution. The table below presents our estimated fuel, purchased power, and other commitments at December 31, 2011. Ameren's and Ameren Missouri's coal commitments include multiyear agreements to procure ultra-low-sulfur coal and related transportation from the Powder River Basin in Wyoming. Ameren's and Ameren Missouri's purchased power obligations include a 102-MW power purchase agreement with a wind farm operator that expires in 2024. Ameren's and Ameren Illinois' purchased power obligations include the Ameren Illinois power purchase agreements entered into as part of the IPA-administered power procurement process. Included in the Other column are minimum purchase commitments under contracts for equipment, design and construction, meter reading services, and an Ameren tax credit obligation at December 31, 2011. Ameren's tax credit obligation is a $17 million note payable issued for an investment in a commercial real estate development partnership to acquire tax credits. This note payable was netted against the related investment in "Other assets" on Ameren's balance sheet at December 31, 2011, as Ameren has a legally enforceable right to offset under authoritative accounting guidance.

	Coal		Natural Gas		Nuclear Fuel		Purchased Power		Methane Gas		Other		Total
Ameren:(a)
2012	$	1,120	$	398	$	36	$	196	$	1	$	221	$	1,972
2013		792		295		37		309		3		80		1,516
2014		692		220		96		125		3		75		1,211
2015		687		116		90		51		3		52		999
2016		674		39		100		52		3		62		930
Thereafter		968		134		298		746		94		246		2,486
Total	$	4,933	$	1,202	$	657	$	1,479	$	107	$	736	$	9,114
Ameren Missouri:
2012	$	623	$	63	$	36	$	19	$	1	$	78	$	820
2013		605		48		37		19		3		50		762
2014		625		36		96		19		3		47		826
2015		614		19		90		19		3		28		773
2016		644		7		100		19		3		38		811
Thereafter		921		30		298		155		94		144		1,642
Total	$	4,032	$	203	$	657	$	250	$	107	$	385	$	5,634
Ameren Illinois:
2012	$	-	$	324	$	-	$	177	$	-	$	24	$	525
2013		-		243		-		290		-		22		555
2014		-		180		-		106		-		22		308
2015		-		94		-		32		-		24		150
2016		-		31		-		33		-		24		88
Thereafter		-		105		-		591		-		102		798
Total	$	-	$	977	$	-	$	1,229	$	-	$	218	$	2,424
Genco:
2012	$	355	$	9	$	-	$	-	$	-	$	98	$	462
2013		108		4		-		-		-		5		117
2014		40		3		-		-		-		5		48
2015		45		2		-		-		-		-		47
2016		-		-		-		-		-		-		-
Thereafter		-		-		-		-		-		-		-
Total	$	548	$	18	$	-	$	-	$	-	$	108	$	674

(a) Includes amounts for Ameren registrant and nonregistrant subsidiaries and intercompany eliminations.

Also, as part of the 2007 Illinois Electric Settlement Agreement, Ameren Illinois entered into financial contracts with Marketing Company to lock in energy prices for 400 to 1,000 megawatts annually of their round-the-clock power requirements from 2008 to 2012. These commitments are not reflected in the above table. See Note 7 – Derivative Financial Instruments and Note 14 – Related Party Transactions for additional information.

In February 2012, a rate stability procurement for energy products and renewable energy credits was administered by the IPA for the June 2013 through May 2017 period to meet certain requirements for purchased power related to the IEIMA. Ameren Illinois contracted to purchase approximately 13 million megawatthours of energy products at an average price of approximately $31 per megawatthour. Ameren Illinois is currently reviewing the results of the renewable energy credits procurement proceeding.

Ameren Illinois has entered into an agreement to purchase approximately 15.5 billion cubic feet of synthetic natural gas annually over a 10-year period beginning in 2016 for its natural gas customers. The agreement is contingent on the counterparty reaching certain milestones during the project development and the construction of the plant that will produce the synthetic natural gas. Construction has not begun on the plant; therefore, Ameren Illinois' obligations are not yet certain at this time. The agreement was entered into pursuant to an Illinois law which became effective August 2, 2011, and provides that all contract costs for synthetic natural gas incurred by Ameren Illinois are reasonable and prudent and recoverable through the PGA and are not subject to review or disallowance by the ICC.

Environmental Matters

We are subject to various environmental laws and regulations enforced by federal, state, and local authorities. From the beginning phases of siting and development to the ongoing operation of existing or new electric generating, transmission and distribution facilities, natural gas storage, transmission and distribution facilities, our activities involve compliance with diverse environmental laws and regulations. These laws and regulations address emissions, impacts to air, land and water, noise, protected natural and cultural resources (such as wetlands, endangered species and other protected wildlife, and archeological and historical resources), and chemical and waste handling. Complex and lengthy processes are required to obtain approvals, permits, or licenses for new, existing or modified facilities. Additionally, the use and handling of various chemicals or hazardous materials (including wastes) requires release prevention plans and emergency response procedures.

In addition to existing laws and regulations, including the Illinois MPS that applies to our energy centers in Illinois, the EPA is developing numerous new environmental regulations that will have a significant impact on the electric utility industry. These regulations could be particularly burdensome for certain companies, including Ameren, Ameren Missouri and Genco, that operate coal-fired energy centers. Significant new rules proposed or promulgated since the beginning of 2010 include the regulation of greenhouse gas emissions; revised national ambient air quality standards for SO₂ and NO₂ emissions; the CSAPR, which requires further reductions of SO₂ and NO_x emissions from power plants; a regulation governing management of CCR and coal ash impoundments; the MATS, which requires reduction of emissions of mercury, toxic metals, and acid gases from power plants; revised NSPS for particulate matter, SO₂, and NO_x emissions from new sources; and new regulations under the Clean Water Act that could require significant capital expenditures such as new water intake structures or cooling towers at our energy centers. The EPA also plans to propose an additional rule, applicable to new and existing electric generating units, governing NSPS and emission guidelines for greenhouse gas emissions. These new regulations may be litigated, so the timing of their implementation is uncertain, as evidenced by the stay of the CSAPR by the United States Court of Appeals for the District of Columbia on December 30, 2011. Although many details of these future regulations are unknown, the combined effects of the new and proposed environmental regulations may result in significant capital expenditures and/or increased operating costs over the next five to ten years for Ameren, Ameren Missouri and Genco. Actions required to ensure that our facilities and operations are in compliance with environmental laws and regulations could be prohibitively expensive. If they are, these regulations could require us to close or to significantly alter the operation of our energy centers, which could have an adverse effect on our results of operations, financial position, and liquidity, including the impairment of plant assets. Failure to comply with environmental laws and regulations might also result in the imposition of fines, penalties, and injunctive measures.

The estimates in the table below contain all of the known capital costs to comply with existing environmental regulations and our assessment of the potential impacts of the EPA's proposed regulation for CCR, the recently finalized MATS, the stayed CSAPR as currently designed, and the revised national ambient air quality standards for SO₂ and NO_x emissions as of December 31, 2011. The estimates in the table below assume that CCR will continue to be regarded as nonhazardous. The estimates in the table below do not include the impacts of new regulations proposed by the EPA under the Clean Water Act in March 2011 regarding cooling water intake structures as our evaluation of those impacts is ongoing. The estimates shown in the table below could change significantly depending upon a variety of factors including:

Ÿ additional federal or state requirements;

Ÿ regulation of greenhouse gas emissions;

Ÿ new national ambient air quality standards or changes to existing standards for ozone, fine particulates, SO₂, and NO_x emissions;

Ÿ additional rules governing air pollutant transport;

Ÿ finalized regulations under the Clean Water Act;

Ÿ CCR being classified as hazardous;

Ÿ whether the CSAPR is implemented and whether any modifications are made to its existing requirements;

Ÿ new technology;

Ÿ expected power prices;

Ÿ variations in costs of material or labor; and

Ÿ alternative compliance strategies or investment decisions.

	2012		2013 - 2016				2017 - 2021				Total
AMO(a)	$	55	$	325 -	$	400	$	845 -	$	1,030	$	1,225 -	$	1,485
Genco		150		100 -		125		245 -		295		495 -		570
AERG		5		20 -		25		80 -		100		105 -		130
Ameren	$	210	$	445 -	$	550	$	1,170 -	$	1,425	$	1,825 -	$	2,185

(a) Ameren Missouri's expenditures are expected to be recoverable from ratepayers.

The decision to make pollution control equipment investments at our Merchant Generation business depends on whether the expected future market price for power reflects the increased cost for environmental compliance. In early 2012, there has been a decline in the market price for wholesale power because of factors such as declining natural gas prices and the stay of the CSAPR. As a result of this decline in the market price for power, as well as uncertain environmental regulations, Genco is decelerating the construction of two scrubbers at of its Newton energy center. These scrubbers were originally expected to be installed in late 2013 and spring 2014. The ultimate installation of these scrubbers, now estimated to occur between 2017 and 2021 in the table above, has been postponed until such time as the incremental investment necessary for completion is justified by visible market conditions. However, Genco will continue to incur capital costs related to the construction of these scrubbers. The table above includes Genco's estimated costs of approximately $150 million in 2012 and approximately $20 million annually, excluding capitalized interest, from 2013 through 2016 for the construction of the two scrubbers. In addition to Genco's reduction in estimated capital expenditures, AERG is deferring precipitator upgrades at its E.D. Edwards energy center beyond 2016.

The following sections describe the more significant environmental rules that affect our operations.

Clean Air Act

Both federal and state laws require significant reductions in SO₂ and NO_x emissions that result from burning fossil fuels. In March 2005, the EPA issued regulations with respect to SO₂ and NO_x emissions (the CAIR). The CAIR required generating facilities in 28 states, including Missouri and Illinois, and the District of Columbia to participate in cap-and-trade programs to reduce annual SO₂ emissions, annual NO_x emissions, and ozone season NO_x emissions.

In December 2008, the United States Court of Appeals for the District of Columbia remanded the CAIR to the EPA for further action to remedy the rule's flaws, but allowed the CAIR's cap-and-trade programs to remain effective until they are replaced by the EPA. In July 2011, the EPA issued the CSAPR as the CAIR replacement. The CSAPR was to become effective on January 1, 2012, for SO₂ and annual NO_x reductions and on May 1, 2012, for ozone season NO_x reductions. In the CSAPR, the EPA developed federal implementation plans for each state covered by this rule; however, each impacted state can develop its own implementation rule starting as early as 2013. The CSAPR establishes emission allowance budgets for each of the states subject to the regulation, including Missouri and Illinois. With the CSAPR, the EPA abandoned CAIR's regional approach to cutting emissions and instead set a pollution budget for each of the impacted states based on the EPA's analysis of each upwind state's contribution to air quality in downwind states. For Missouri and Illinois, emission reductions were required in two phases beginning in 2012, with further reductions in 2014. With the CSAPR, the EPA adopted a cap-and-trade approach that allows intrastate and limited interstate trading of emission allowances with other sources within the same program, that is, in the SO₂ program, in the annual NO_x, or in ozone season NO_x program. Multiple legal challenges were filed requesting to have CSAPR partially or entirely vacated and to stay the implementation of the CSAPR while the court considers the challenges. On December 30, 2011, the United States Court of Appeals for the District of Columbia issued a stay of the CSAPR. The stay does not invalidate the rule, but only delays its implementation until a final court ruling is issued. The United States Court of Appeals for the District of Columbia has expedited its consideration of the regulation and will hear arguments on the validity of CSAPR in April 2012. The ultimate outcome of the challenges to the regulation is uncertain. The court could uphold CSAPR or remand it back to the EPA for partial or entire revision. Until the CSAPR appeal process is concluded, the EPA will continue to administer the CAIR.

On December 21, 2011, the EPA issued the final MATS under the Clean Air Act, which require emission reductions for mercury and other hazardous air pollutants, such as acid gases, toxic metals, and particulate matter by setting emission limits equal to the average emissions of the best performing 12% of existing coal and oil-fired electric generating units. Also, the rule requires reductions in hydrogen chloride emissions, which were not regulated previously, and it may require continuous monitoring systems that are not currently in place. The MATS do not require a specific control technology to achieve the emission reductions. The MATS will apply to each unit at a coal-fired power plant; however, emission compliance can be averaged for the entire power plant. Compliance is required by April 2015 or, with a case-by-case extension, by April 2016.

Separately, in January and June 2010, the EPA finalized new ambient air quality standards for SO₂ and NO₂. It also announced plans for further reductions in the annual national ambient air quality standards for ozone and fine particulates. The state of Illinois and the state of Missouri will be required to develop separate attainment plans to comply with the new ambient air quality standards. Ameren, Ameren Missouri and Genco continue to assess the impacts of these new standards. In September 2011, the EPA withdrew its draft annual national ambient air quality standard for ozone and announced that it was implementing the 2008 national ambient air quality standard for ozone. The EPA is required to revisit this standard again in 2013.

Ameren Missouri's current environmental compliance plan for air emissions from its energy centers includes burning ultra-low-sulfur coal and installing new or optimizing existing pollution control equipment. In July 2011, Ameren Missouri contracted to procure significantly higher volumes of lower-sulfur-content coal than Ameren Missouri's energy centers have historically burned, which will allow Ameren Missouri to eliminate or postpone capital expenditures for pollution control equipment while still achieving required emissions levels. In 2010, Ameren Missouri completed the installation of two scrubbers at its Sioux energy center to reduce SO₂ emissions. Currently, Ameren Missouri's compliance plan assumes the installation of two scrubbers within its coal-fired fleet during the next 10 years and precipitator upgrades at multiple energy centers. However, Ameren Missouri is currently evaluating its operations and options to determine how to comply with the additional emission reductions requirements in 2014 set forth in the CSAPR, if ultimately enacted, the MATS, and other recently finalized or proposed EPA regulations.

Existing Illinois state regulations already required Ameren and Genco to reduce their emissions of mercury under the MPS. Ameren's and Genco's review of the MATS indicates that the scope of the federal standards is broader than the MPS, as no exemption exists for smaller coal-fired plants. Additionally, the MATS are more stringent than the MPS because compliance with the MATS is measured on a quarterly basis and, in some cases, a thirty-day rolling basis and not annually, as allowed under state requirements. At the end of 2011, Genco ceased operations of its Meredosia and Hutsonville energy centers. The closure of these energy centers was primarily due to the expected cost of complying with CSAPR and MATS. See Note 17 – Goodwill, Impairment and Other Charges for additional information.

Genco and AERG expect to install additional, or optimize existing, pollution control equipment, or modify operations to meet new and incremental emission reduction requirements under the MPS, the MATS, or the CSAPR as they become effective. Under the MPS, as amended, Illinois generators are required to reduce mercury, SO₂, and NO_x emissions by 2015. To comply with the MPS and other air emissions laws and regulations, Genco and AERG are installing equipment designed to reduce their emissions of mercury, NO_x, and SO₂. Genco and AERG have installed a total of three scrubbers at two energy centers. Two additional scrubbers are being constructed at Genco's Newton energy center. As discussed above, the timing of the installation of these scrubbers as well as precipitator upgrades at AERG's E.D. Edwards energy center have been extended. The closure of Genco's Meredosia and Hutsonville energy centers will allow the Merchant Generation segment additional flexibility in the methods to achieve compliance with environmental standards. Merchant Generation and Genco will continue to review and adjust their compliance plans in light of evolving outlooks for power and capacity prices, delivered fuel costs, environment standards and compliance technologies, among other factors.

The completion of Ameren's, Ameren Missouri's and Genco's review of recently finalized environmental regulations and compliance measures could result in significant increases in capital expenditures and operating costs. The compliance costs could be prohibitive at some of our energy centers as the expected return from these investments, at current market prices for energy and capacity, might not justify the required capital expenditures or their continued operation, which could result in the impairment of long-lived assets.

Emission Allowances

The Clean Air Act created marketable commodities called allowances under the acid rain program, the NO_x budget trading program, the CAIR, and the CSAPR. With the CSAPR, the EPA adopted a cap-and-trade approach that allows intrastate and limited interstate trading of emission allowances with other sources within the same program, that is, either the SO₂, annual NO_x, or ozone season NO_x programs. As noted above, on December 30, 2011, the United States Court of Appeals for the District of Columbia issued a stay of the CSAPR. Until the CSAPR appeal process is concluded, the EPA will continue to administer the CAIR including its allowance program. See Note 1 – Summary of Significant Accounting Policies for the SO₂ and NO_x emission allowance book values that were classified as intangible assets as of December 31, 2011 and 2010, and Note 17 – Goodwill, Impairment and Other Charges for information regarding the emission allowance impairments recorded during 2011 and 2010.

Environmental regulations including the CAIR and the CSAPR, the timing of the installation of pollution control equipment, fuel mix, and the level of operations, will have a significant impact on the number of allowances required for ongoing operations. The CAIR uses the acid rain program's allowances for SO₂ emissions and created annual and ozone season NO_x allowances. The CSAPR, however, will not rely upon the acid rain program, the NO_x budget trading program, or CAIR allowances for its allowance allocation program. Instead, the EPA issued a new type of emissions allowance for each program under the CSAPR. Any unused SO₂ allowances, annual NO_x allowances, and ozone season NO_x allowances issued under CAIR cannot be used for compliance with CSAPR. Ameren, Ameren Missouri and Genco expect to have adequate CAIR allowances for 2012 to avoid needing to make external purchases.

Should the CSAPR become effective as issued, Ameren, Ameren Missouri and Genco are studying their compliance options to identify additional opportunities that may exist for compliance in an economical fashion. Ameren, Ameren Missouri and Genco may be required to purchase emission allowances, if available, to install new or optimize existing pollution control equipment, to limit generation, or take other actions to achieve compliance with the CSAPR in future phase-in years.

Global Climate Change

State and federal authorities, including the United States Congress, have considered initiatives to limit greenhouse gas emissions and to address global climate change. Potential impacts from any climate change legislation or regulation could vary, depending upon proposed CO₂ emission limits, the timing of implementation of those limits, the method of distributing any allowances, the degree to which offsets are allowed and available, and provisions for cost-containment measures, such as a "safety valve" provision that provides a maximum price for emission allowances. As a result of our diverse fuel portfolio, our emissions of greenhouse gases vary among our energy centers, but coal-fired power plants are significant sources of CO₂. The enactment of a climate change law could result in a significant rise in household costs and rates for electricity could rise significantly. The burden could fall particularly hard on electricity consumers and upon the economy in the Midwest because of the region's reliance on electricity generated by coal-fired power plants. Natural gas emits about half as much CO₂ as coal when burned to produce electricity. Therefore, climate change regulation could cause the conversion of coal-fired power plants to natural gas, or the construction of new natural gas plants to replace coal-fired power plants. As a result, economywide shifts to natural gas as a fuel source for electricity generation also could affect the cost of heating for our utility customers and many industrial processes that use natural gas.

In December 2009, the EPA issued its "endangerment finding" under the Clean Air Act which stated that greenhouse gas emissions, including CO₂, endanger human health and welfare and that emissions of greenhouse gases from motor vehicles contribute to that endangerment. In March 2010, the EPA issued a determination that greenhouse gas emissions from stationary sources, such as power plants, would be subject to regulation under the Clean Air Act effective the beginning of 2011. As a result of these actions, we are required to consider the emissions of greenhouse gases in any air permit application.

Recognizing the difficulties presented by regulating at once virtually all emitters of greenhouse gases, the EPA finalized in May 2010 regulations, known as the "Tailoring Rule," that established new higher thresholds for regulating greenhouse gas emissions from stationary sources, such as power plants. The Tailoring Rule became effective in January 2011. The rule requires any source that already has an operating permit to have greenhouse-gas-specific provisions added to its permits upon renewal. Currently, all Ameren energy centers have operating permits that, when renewed, may be modified to address greenhouse gas emissions. The Tailoring Rule also provides that if projects performed at major sources result in an increase in emissions of greenhouse gases of at least 75,000 tons per year, measured in CO₂ equivalents, such projects could trigger permitting requirements under the NSR programs and the application of best available control technology, if any, to control greenhouse gas emissions. New major sources are also required to obtain such a permit and to install the best available control technology if their greenhouse gas emissions exceed the applicable emissions threshold. Separately, in December 2010, the EPA announced a settlement agreement under which it would propose NSPS for greenhouse gas emissions at new and existing fossil fuel-fired power plants by July 26, 2011 and issue a final standard by May 2012. The EPA has not yet proposed a rule and has not specified a new estimate of when it will issue that standard. It is uncertain whether reductions to greenhouse gas emissions would be required at Ameren's, Ameren Missouri's or Genco's energy centers as a result of any of the EPA's new and future rules. Legal challenges to the EPA's greenhouse gas rules have been filed. Any federal climate change legislation that is enacted may preempt the EPA's regulation of greenhouse gas emissions, including the Tailoring Rule, particularly as it relates to power plant greenhouse gas emissions. The extent to which the Tailoring Rule could have a material impact on our energy centers depends upon how state agencies apply the EPA's guidelines as to what constitutes the best available control technology for greenhouse gas emissions from power plants and whether physical changes or changes in operations subject to the rule occur at our energy centers. Although the EPA has stated its intention to regulate greenhouse gas emissions from stationary sources, such as power plants, congressional action could block or delay that effort.

Future federal and state legislation or regulations that mandate limits on the emission of greenhouse gases would likely result in significant increases in capital expenditures and operating costs, which, in turn, could lead to increased liquidity needs and higher financing costs. Moreover, to the extent Ameren Missouri requests recovery of these costs through rates, its regulators might delay or deny timely recovery of these costs. Excessive costs to comply with future legislation or regulations might force Ameren, Ameren Missouri and Genco as well as other similarly situated electric power generators to close some coal-fired facilities earlier than planned, which could lead to possible impairment of assets and reduced revenues. As a result, mandatory limits could have a material adverse impact on Ameren's, Ameren Missouri's, and Genco's results of operations, financial position, and liquidity.

Recent federal court decisions have considered the application of common law causes of action, such as nuisance, to address damages resulting from global climate change. In June 2011, the United States Supreme Court in State of Connecticut v. American Electric Power rejected state efforts to impose liability for CO₂ and greenhouse gases emissions under federal common law. That ruling, however, did not address whether private citizens could pursue causes of action based on state common law. In June 2011, a case called Comer v. Murphy Oil (Comer) was filed in the United States District Court for the Southern District of Mississippi. In this litigation, a Mississippi property owner sued several industrial companies, including Ameren Missouri and Genco, alleging that CO₂ emissions created the atmospheric conditions that intensified Hurricane Katrina. Although we are unable to predict the outcome of the Comer litigation on our results of operations, financial position, and liquidity, Ameren believes that it has meritorious defenses. Numerous procedural and substantive challenges are expected in the Comer litigation.

The impact on us of future initiatives related to greenhouse gas emissions and global climate change is unknown. Compliance costs could increase as future federal legislative, federal regulatory, and state-sponsored initiatives to control greenhouse gases continue to progress, making it more likely that some form of greenhouse gas emissions control will eventually be required. Since these initiatives continue to evolve, the impact on our coal-fired energy centers and our customers' costs is unknown, but any impact would probably be negative. Our costs of complying with any mandated federal or state greenhouse gas program could have a material impact on our future results of operations, financial position, and liquidity.

NSR and Clean Air Litigation

The EPA is engaged in an enforcement initiative to determine whether coal-fired power plants failed to comply with the requirements of the NSR and NSPS provisions under the Clean Air Act when the plants implemented modifications. The EPA's inquiries focus on whether projects performed at power plants should have triggered various permitting requirements and the installation of pollution control equipment.

In April 2005, Genco received a request from the EPA for information pursuant to Section 114(a) of the Clean Air Act. The request sought detailed operating and maintenance history data with respect to Genco's Coffeen, Hutsonville, Meredosia, Newton, and Joppa energy centers and AERG's E.D. Edwards and Duck Creek energy centers. In 2006, the EPA issued a second Section 114(a) request to Genco regarding projects at the Newton energy center. All of these facilities are coal-fired energy centers. In September 2008, the EPA issued a third Section 114(a) request regarding projects at all of Ameren's coal-fired energy centers in Illinois. We completed our response to the information requests, but we are unable to predict the outcome of this matter.

Following the issuance of a Notice of Violation, in January 2011, the Department of Justice on behalf of the EPA filed a complaint against Ameren Missouri in the United States District Court for the Eastern District of Missouri. The EPA's complaint alleges that in performing projects at its Rush Island coal-fired energy center, Ameren Missouri violated provisions of the Clean Air Act and Missouri law. In January 2012, the United States District Court granted, in part, Ameren Missouri's motion to dismiss various aspects of the EPA's penalty claims. The EPA's claims for injunctive relief, including to require the installation of pollution control equipment, remain. At present, the complaint does not include Ameren Missouri's other coal-fired energy centers, but the EPA has issued Notices of Violation under its NSR enforcement initiative against the company's Labadie, Meramec, and Sioux coal-fired energy centers. Litigation of this matter could take many years to resolve. Ameren Missouri believes its defenses to the allegations described in the complaint as well as the Notices of Violation are meritorious. Ameren Missouri will defend itself vigorously. However, there can be no assurances that it will be successful in its efforts.

Ultimate resolution of these matters could have a material adverse impact on the future results of operations, financial position, and liquidity of Ameren, Ameren Missouri and Genco. A resolution could result in increased capital expenditures for the installation of pollution control equipment, increased operations and maintenance expenses, and penalties. We are unable to predict the ultimate resolution of these matters or the costs that might be incurred. However, Ameren Missouri has concluded that, while a loss may be reasonably possible, the likelihood of loss is not probable. Therefore, no reserve has been established.

Clean Water Act

In March 2011, the EPA announced a proposed rule applicable to cooling water intake structures at existing power plants that have the ability to withdraw more than 2 million gallons of water per day from a body of water and use at least 25 percent of that water exclusively for cooling. Under the proposed rule, affected facilities would be required either to meet mortality limits for aquatic life impinged on the plant's intake screens or to reduce intake velocity to 0.5 feet per second. The proposed rule also requires plants to meet site-specific entrainment standards or to reduce the cooling water intake flow commensurate with the intake flow of a closed-cycle cooling system. The final rule is scheduled to be issued in July 2012, with compliance expected within eight years thereafter. All coal-fired, nuclear, and combined cycle energy centers at Ameren, Ameren Missouri and Genco with cooling water systems are subject to this proposed rule. The proposed rule did not mandate cooling towers at existing facilities, as other technology options potentially could meet the site-specific standards. Ameren, Ameren Missouri and Genco are currently evaluating the proposed rule, and their assessment of the proposed rule's impacts is ongoing. Therefore, we cannot predict at this time the capital or operating costs associated with compliance. The proposed rule could have an adverse effect on our results of operations, financial position, and liquidity if its implementation requires the installation of cooling towers at our electric generating stations.

In September 2009, the EPA announced its plan to revise the effluent guidelines applicable to steam electric generating units under the Clean Water Act. Effluent guidelines are national standards for wastewater discharges to surface water that are based on the effectiveness of available control technology. The EPA is engaged in information collection and analysis activities in support of this rulemaking. It has indicated that it expects to issue a proposed rule in July 2012 and to finalize the rule in 2014. We are unable at this time to predict the impact of this development.

Remediation

We are involved in a number of remediation actions to clean up hazardous waste sites as required by federal and state law. Such statutes require that responsible parties fund remediation actions regardless of their degree of fault, the legality of original disposal, or the ownership of a disposal site. Ameren Missouri and Ameren Illinois have each been identified by the federal or state governments as a potentially responsible party (PRP) at several contaminated sites. Several of these sites involve facilities that were transferred by our rate-regulated utility operations in Illinois to Genco in May 2000 and to AERG in October 2003. As part of each transfer, Ameren Illinois contractually agreed to indemnify Genco and AERG for remediation costs associated with preexisting environmental contamination at the transferred sites.

As of December 31, 2011, Ameren and Ameren Illinois owned or were otherwise responsible for 44 former MGP sites in Illinois. These are in various stages of investigation, evaluation, and remediation. Based on current estimated plans, Ameren and Ameren Illinois could substantially conclude remediation efforts at most of these sites by 2015. The ICC permits Ameren Illinois to recover remediation and litigation costs associated with its former MGP sites from its electric and natural gas utility customers through environmental adjustment rate riders. To be recoverable, such costs must be prudently and properly incurred. Costs are subject to annual review by the ICC.

As of December 31, 2011, Ameren and Ameren Missouri own or are otherwise responsible for 10 MGP sites in Missouri and one site in Iowa. Ameren Missouri does not currently have a rate rider mechanism that permits recovery of remediation costs associated with MGP sites from utility customers. Ameren Missouri does not have any retail utility operations in Iowa that would provide a source of recovery of these remediation costs.

The following table presents, as of December 31, 2011, the estimated probable obligation to remediate these MGP sites.

	Estimate				Recorded Liability(a)
	Low		High
Ameren	$	107	$	183	$	107
Ameren Missouri		3		4		3
Ameren Illinois		104		179		104

(a) Recorded liability represents the estimated minimum probable obligations, as no other amount within the range provided a better estimate.

Ameren Illinois is responsible for the cleanup of a former coal ash landfill in Coffeen, Illinois. As of December 31, 2011, Ameren Illinois estimated that obligation at $0.5 million to $6 million. Ameren Illinois recorded a liability of $0.5 million to represent its estimated minimum obligation for this site, as no other amount within the range was a better estimate. Ameren Illinois is also responsible for the cleanup of a landfill, underground storage tanks, and a water treatment plant in Illinois. As of December 31, 2011, Ameren Illinois recorded a liability of $0.8 million to represent its best estimate of the obligation for these sites.

Ameren Missouri has responsibility for the investigation and potential cleanup of two waste sites in Missouri as a result of federal agency mandates. One of the cleanup sites is a former coal tar distillery located in St. Louis, Missouri. In 2008, the EPA issued an administrative order to Ameren Missouri pertaining to this distillery operated by Koppers Company or its predecessor and successor companies. Ameren Missouri is the current owner of the site, but Ameren Missouri did not conduct any of the manufacturing operations involving coal tar or its byproducts. Ameren Missouri, along with two other PRPs, is currently performing a site investigation. As of December 31, 2011, Ameren Missouri estimated its obligation at $2 million to $5 million. Ameren Missouri has a liability of $2 million recorded to represent its estimated minimum obligation, as no other amount within the range was a better estimate. Ameren Missouri's other active federal agency-mandated cleanup site in Missouri is a site in Cape Girardeau. Ameren Missouri was a customer of an electrical equipment repair and disposal company that previously operated a facility at this site. A trust was established in the early 1990s by several businesses and governmental agencies to fund the cleanup of this site, which was completed in 2005. Ameren Missouri anticipates this trust fund will be sufficient to complete the remaining adjacent off-site cleanup and therefore has no recorded liability at December 31, 2011, related to this site.

Ameren Missouri also has a federal agency mandate to complete a site investigation for a site in Illinois. In 2000, the EPA notified Ameren Missouri and numerous other companies, including Solutia, that former landfills and lagoons in Sauget, Illinois, may contain soil and groundwater contamination. These sites are known as Sauget Area 2. From about 1926 until 1976, Ameren Missouri operated an energy center adjacent to Sauget Area 2. Ameren Missouri currently owns a parcel of property that was once used as a landfill. Under the terms of an Administrative Order on Consent, Ameren Missouri has joined with other PRPs to evaluate the extent of potential contamination with respect to Sauget Area 2.

The Sauget Area 2 investigations overseen by the EPA have been completed. The results have been submitted to the EPA, and a record of decision is expected in 2012. Once the EPA has selected a remedy, if any, it would begin negotiations with various PRPs regarding implementation. Over the last several years, numerous other parties have joined the PRP group. In addition, Pharmacia Corporation and Monsanto Company have agreed to assume the liabilities related to Solutia's former chemical waste landfill in the Sauget Area 2. As of December 31, 2011, Ameren Missouri estimated its obligation at $0.3 million to $10 million. Ameren Missouri has a liability of $0.3 million recorded to represent its estimated minimum obligation, as no other amount within the range was a better estimate.

In December 2004, AERG submitted a plan to the Illinois EPA to address groundwater and surface water issues associated with the recycle pond, ash ponds, and reservoir at the Duck Creek energy center. In 2010, AERG closed the recycle pond system. Remediation work on the recycle pond was completed in the first quarter of 2011, and therefore no liability exists as of December 31, 2011.

Our operations or those of our predecessor companies involve the use of, disposal of, and in appropriate circumstances, the cleanup of substances regulated under environmental protection laws. We are unable to determine whether such practices will result in future environmental commitments or affect our results of operations, financial position, or liquidity.

Ash Management

There has been activity at both state and federal levels regarding additional regulation of ash pond facilities and CCR. In May 2010, the EPA announced proposed new regulations regarding the regulatory framework for the management and disposal of CCR, which could affect future disposal and handling costs at our energy centers. Those proposed regulations include two options for managing CCRs under either solid or hazardous waste regulations, but either alternative would allow for some continued beneficial uses, such as recycling of CCR without classifying it as waste. As part of its proposal, the EPA is considering alternative regulatory approaches that require coal-fired power plants either to close surface impoundments, such as ash ponds, or to retrofit such facilities with liners. Existing impoundments and landfills used for the disposal of CCR would be subject to groundwater monitoring requirements and requirements related to closure and postclosure care under the proposed regulations. Additionally, in January 2010, EPA announced its intent to develop regulations establishing financial responsibility requirements for the electric generation industry, among other industries, and it specifically discussed CCR as a reason for developing the new requirements. Ameren, Ameren Missouri and Genco are currently evaluating all of the proposed regulations to determine whether current management of CCR, including beneficial reuse, and the use of the ash ponds should be altered. Ameren, Ameren Missouri and Genco also are evaluating the potential costs associated with compliance with the proposed regulation of CCR impoundments and landfills, which could be material, if such regulations are adopted.

In addition, the Illinois EPA requested that Ameren, Ameren Missouri and Genco establish groundwater monitoring plans for their ash impoundments in Illinois. Ameren and the Illinois EPA have established a framework for closure of ash ponds in Illinois, including the ash ponds at Venice, Hutsonville, and Duck Creek, when such facilities are ultimately taken out of service. Ameren, Ameren Missouri and Genco have recorded AROs, based on current laws, for the estimated costs of the retirement of their ash ponds.

Pumped-storage Hydroelectric Facility Breach

In December 2005, there was a breach of the upper reservoir at Ameren Missouri's Taum Sauk pumped-storage hydroelectric energy center. This resulted in significant flooding in the local area, which damaged a state park. Ameren Missouri settled with FERC and the state of Missouri all issues associated with the December 2005 Taum Sauk incident. The rebuilt Taum Sauk energy center became fully operational in April 2010.

Ameren Missouri included certain capitalized costs associated with enhancements, or costs that would have been incurred absent the breach, at the rebuilt Taum Sauk energy center not recovered from property insurers in its 2010 electric rate case filing. However, in the July 2011 rate order, the MoPSC disallowed all of these capitalized costs associated with the rebuilding of the Taum Sauk energy center. As a result of the order, Ameren and Ameren Missouri each recorded a pretax charge to earnings in 2011 of $89 million to reflect this disallowance. See Note 2 – Rate and Regulatory Matters for additional information about the appeal of the MoPSC's July 2011 electric rate order.

Ameren Missouri had property and liability insurance coverage for the Taum Sauk incident, subject to certain limits and deductibles. Insurance did not cover some lost electric margins or penalties paid to FERC. Ameren Missouri believes that the total cost for cleanup, damage and liabilities, excluding costs to rebuild the upper reservoir, is $209 million, which is the amount Ameren Missouri had paid as of December 31, 2011. As of December 31, 2011, Ameren Missouri had recorded expenses of $37 million, primarily in prior years (2011 – $1 million, 2010 – $1 million, 2009 – $2 million), for items not covered by insurance. Ameren Missouri recorded a $172 million receivable for amounts recoverable from insurance companies under liability coverage. As of December 31, 2011, Ameren Missouri had received $104 million from insurance companies for liability claims, which reduced the insurance receivable balance subject to liability coverage to $68 million.

In June 2010, Ameren Missouri sued an insurance company that was providing Ameren Missouri with liability coverage on the date of the Taum Sauk incident. In the litigation, filed in the United States District Court for the Eastern District of Missouri, Ameren Missouri claimed the insurance company breached its duty to indemnify Ameren Missouri for the losses experienced from the incident. In January 2011, the court ruled that the parties must first pursue alternative dispute resolution under the terms of their coverage agreement. In February 2011, Ameren Missouri filed an appeal of the January ruling with the United States Court of Appeals for the Eighth Circuit, seeking the ability to pursue resolution of this dispute outside of a dispute resolution process under the terms of its coverage agreement.

Until Ameren's remaining liability insurance claims and the related litigation are resolved, we are unable to determine the total impact the breach could have on Ameren's and Ameren Missouri's results of operations, financial position, and liquidity beyond those amounts already recognized.

Asbestos-related Litigation

Ameren, Ameren Missouri, Ameren Illinois and EEI have been named, along with numerous other parties, in a number of lawsuits filed by plaintiffs claiming varying degrees of injury from asbestos exposure. Most have been filed in the Circuit Court of Madison County, Illinois. The total number of defendants named in each case varies, with as many as 272 parties named in some pending cases and as few as two in others. In the cases pending as of December 31, 2011, the average number of parties was 80.

The claims filed against Ameren, Ameren Missouri, Ameren Illinois and Genco allege injury from asbestos exposure during the plaintiffs' activities at our present or former electric generating plants. Former CIPS plants are now owned by Genco, and former CILCO plants are now owned by AERG. As a part of the transfer of ownership of the CIPS and CILCO generating plants, CIPS and CILCO, now Ameren Illinois, contractually agreed to indemnify Genco and AERG, for liabilities associated with asbestos-related claims arising from activities prior to the transfer. Each lawsuit seeks unspecified damages that, if awarded at trial, typically would be shared among the various defendants.

The following table presents the pending asbestos-related lawsuits filed against the Ameren Companies as of December 31, 2011:

Ameren	Ameren Missouri	Ameren Illinois	Genco	Total(a)
4	53	77	(b)	93

(a) Total does not equal the sum of the subsidiary unit lawsuits because some of the lawsuits name multiple Ameren entities as defendants.

(b) As of December 31, 2011, six asbestos-related lawsuits were pending against EEI. The general liability insurance maintained by EEI provides coverage with respect to liabilities arising from asbestos-related claims.

At December 31, 2011, Ameren, Ameren Missouri, Ameren Illinois and Genco had liabilities of $18 million, $6 million, $12 million, and $- million, respectively, recorded to represent their best estimate of their obligations related to asbestos claims.

Ameren Illinois has a tariff rider to recover the costs of asbestos-related litigation claims, subject to the following terms: 90% of cash expenditures in excess of the amount included in base electric rates are to be recovered from a trust fund that was established when Ameren acquired IP. At December 31, 2011, the trust fund balance was $23 million, including accumulated interest. If cash expenditures are less than the amount in base rates, Ameren Illinois will contribute 90% of the difference to the fund. Once the trust fund is depleted, 90% of allowed cash expenditures in excess of base rates will be recovered through charges assessed to customers under the tariff rider. Following the Ameren Illinois Merger, this rider is applicable only for claims that occurred within IP's historical service territory. Similarly, the rider will permit recovery only from customers within IP's historical service territory.

Illinois Sales and Use Tax Exemptions and Credits

In Exelon Corporation v. Department of Revenue, the Illinois Supreme Court decided in 2009 that electricity is tangible personal property for purposes of the Illinois income tax investment credit. In March 2010, the United States Supreme Court refused to hear the case, and the decision became final. During the second quarter of 2010, Genco and AERG began claiming Illinois sales and use tax exemptions and credits for purchase transactions related to their generation operations. The basis for those claims is that the determination in the Exelon case that electricity is tangible personal property applies to sales and use tax manufacturing exemptions and credits. On November 2, 2011, EEI received a notice of proposed tax liability, documenting the state of Illinois' position that EEI did not qualify for the manufacturing exemption it used during 2010. Genco is challenging the State of Illinois' position. In December 2011, EEI filed a request for review by the Informal Conference Board of the Illinois Department of Revenue. Ameren and Genco do not believe that it is probable that the state of Illinois will prevail and therefore have not recorded a charge to earnings for the loss contingency. From the second quarter of 2010 through December 31, 2011, Ameren and Genco claimed manufacturing exemptions and credits of $27 million and $19 million, respectively.