8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of report (Date of earliest event reported):    February 24, 2017

Commission File Number	Exact Name of Registrant as Specified in Charter; State of Incorporation; Address and Telephone Number	IRS Employer Identification Number
1-8962	Pinnacle West Capital Corporation (an Arizona corporation) 400 North Fifth Street, P.O. Box 53999 Phoenix, AZ 85072-3999 (602) 250-1000	86-0512431
1-4473	Arizona Public Service Company (an Arizona corporation) 400 North Fifth Street, P.O. Box 53999 Phoenix, AZ 85072-3999 (602) 250-1000	86-0011170

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

This combined Form 8-K is separately filed or furnished by Pinnacle West Capital Corporation and Arizona Public Service Company. Each registrant is filing or furnishing on its own behalf all of the information contained in this Form 8-K that relates to such registrant and, where required, its subsidiaries. Except as stated in the preceding sentence, neither registrant is filing or furnishing any information that does not relate to such registrant, and therefore makes no representation as to any such information.

Item 2.02. Results of Operations and Financial Condition.

The following information is furnished pursuant to Item 2.02.

On February 24, 2017, Pinnacle West Capital Corporation (the “Company” or “Pinnacle West”) issued a press release regarding its financial results for the fiscal quarter and full year ended December 31, 2016.  A copy of the press release is attached hereto as Exhibit 99.1.

Item 7.01. Regulation FD Disclosure.

The following information is furnished pursuant to Item 7.01.

The Company is providing a copy of the slide presentation made in connection with its earnings conference call on February 24, 2017.  This information contains Company operating results for the fiscal quarter and fiscal year ended December 31, 2016. The slide presentation is attached hereto as Exhibits 99.2 and is concurrently being posted to the Company’s website at www.pinnaclewest.com.

Item 9.01.Financial Statements and Exhibits.

(d)Exhibits

Exhibit No.	Registrant(s)	Description
99.1	Pinnacle West APS	Earnings News Release issued on February 24, 2017.
99.2	Pinnacle West APS	Pinnacle West 4th Quarter and Full-Year 2016 Results slide presentation accompanying February 24, 2017 conference call.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, each registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	PINNACLE WEST CAPITAL CORPORATION
	(Registrant)
Dated: February 24, 2017	By: /s/ James R. Hatfield
	James R. Hatfield
	Executive Vice President and
	Chief Financial Officer
	ARIZONA PUBLIC SERVICE COMPANY
	(Registrant)
Dated: February 24, 2017	By: /s/ James R. Hatfield
	James R. Hatfield
	Executive Vice President and
	Chief Financial Officer

Exhibit Index

Exhibit No.	Registrant(s)	Description
99.1	Pinnacle West APS	Earnings News Release issued on February 24, 2017.
99.2	Pinnacle West APS	Pinnacle West 4th Quarter and Full-Year 2016 Results slide presentation accompanying February 24, 2017 conference call.

EX-99.1

FOR IMMEDIATE RELEASE		February 24, 2017
Media Contact: Analyst Contact:	Alan Bunnell, (602) 250-3376 Ted Geisler (602) 250-3200 Chalese Haraldsen (602) 250-5643
Website:	pinnaclewest.com

PINNACLE WEST REPORTS 2016 FULL-YEAR AND FOURTH-QUARTER RESULTS

• Full-year results benefit from strong operational performance and cost management

• Palo Verde Nuclear Generating Station continues record-breaking performance

• Company makes progress on key regulatory initiatives

PHOENIX - Pinnacle West Capital Corporation (NYSE: PNW) today reported consolidated net income attributable to common shareholders of $442.0 million, or $3.95 per diluted share, for full-year 2016. This result compares with net income of $437.3 million, or $3.92 per share, in 2015.

“Reflecting steady improvement in Arizona’s economic conditions and our employees’ continued focus on sustainable cost management, our year-end results were in line with our expectations,” said Pinnacle West Chairman, President and Chief Executive Officer Don Brandt. “In addition, our employees contributed to strong operational performance, including a record-setting performance at the Palo Verde Nuclear Generating Station.”

Palo Verde achieved its 25th consecutive year as the nation’s largest power producer - producing 32.3 million megawatt-hours of carbon-free electricity. The plant’s three units achieved a capacity factor of 93.2 percent, and Unit 3’s fall 2016 refueling and maintenance outage was the shortest in plant history at 28 days, 17 hours. By comparison, the average length of a refueling and maintenance outage at all U.S. reactors in 2015 was 36.3 days, according to most recent industry data.

Brandt cited additional examples of the Company’s 2016 achievements:

• For the fifth straight year, Pinnacle West increased its common dividend, raising it by 4.8 percent.

• On October 1, the company commenced participation in the western regional Energy Imbalance Market (EIM), resulting in trading efficiencies and customer savings of about $6 million during the 2016 fourth quarter.

• Arizona Public Service (APS) launched a suite of new tools that provides customers with an improved and more customized service experience, including a mobile app, an online outage map and a new automated phone system.

• APS continued investing in an advanced energy grid, including new technologies that enable customers to have greater choice and control over their energy use, while increasing reliability. These technologies included two separate “next generation” microgrids installed in Phoenix and at the Marine Corps Air Station in Yuma, Ariz.

• The Red Rock Solar Plant - APS’s largest self-owned grid-scale solar power plant at 40 megawatts - also was completed, helping the company reach one gigawatt of solar on its system and becoming the only utility outside California to achieve this milestone. To date, the company’s total investment in solar energy is about $2 billion.

• APS’s power reliability for 2016 remained among the strongest in the industry and received a top-quartile score from JD Power for “Power Quality & Reliability” among residential customers.

Looking forward, Brandt said the company remains committed to investing in infrastructure that creates value for customers and shareholders alike, while also building on the positive regulatory outcome in Arizona’s value and cost of distributed generation docket, which was decided in late 2016.

“We will continue to work collaboratively with regulators and other stakeholders on key issues important to Arizona’s energy future, including achieving a constructive regulatory outcome in our current rate review,” he said. “In many respects, this case serves as a transition from the challenges of the present to the opportunities of the future. “

The 2016 full-year financial results comparison was positively impacted by the following major factors:

• Higher lost fixed cost recovery revenue, an increase in transmission proceeds and revenue from the Company’s AZ Sun program improved earnings by $0.18 per share compared to 2015.

• Retail electricity sales improved earnings $0.05 per share due to changes in customer usage patterns and related pricing. Compared to a year ago, total customer growth improved 1.4 percent.

• The effects of weather variations improved the Company’s earnings by $0.02 per share, although weather was still unfavorable compared to normal. For the year, the company had a 6 percent decrease in cooling degree-days and a 5 percent decrease in heating degree-days (measures of the effects of weather) versus 2015. Compared to 10-year historical averages, cooling and heating degree days were down 2.7 percent and 18.7 percent, respectively.

• Lower interest expense, net of AFUDC, contributed $0.02 per share.

• The net effect of miscellaneous items increased earnings $0.06 per share, including the second-quarter sale of a 50 percent ownership stake in an existing transmission line, which resulted in a $0.03 contribution to the Company’s bottom line in the second quarter.

The above positive factors were largely offset by higher operations and maintenance expenses, which reduced annual earnings by $0.30 per share. These expenses were largely associated with major planned outages at the company’s Four Corners Power Plant in the first half of the year;

higher transmission, distribution and customer service costs associated with implementation of new systems; and higher employee benefit costs, among other items.

For the quarter ended December 31, 2016, Pinnacle West reported consolidated net income attributable to common shareholders of $53.2 million, or $0.47 per diluted share. This result compares with net income of $41.1 million, or $0.37 per share, for the same period a year ago.

The 2016 fourth-quarter results comparison versus the same 2015 period was positively impacted by lower operating expenses, partially offset by lower retail electricity sales. While October 2016 proved to be hotter than average, sales decreased in the last two months of the year, with December turning out to be the third mildest December since 1970 - a span of 46 years.

Conference Call and Webcast

Pinnacle West invites interested parties to listen to the live webcast of management’s conference call to discuss the Company’s 2016 year-end and fourth-quarter results, as well as recent developments, at 11 a.m. ET (9 a.m. AZ time) today, February 24. The webcast can be accessed at pinnaclewest.com/presentations and will be available for replay on the website for 30 days. To access the live conference call by telephone, dial (877) 407-8035 or (201) 689-8035 for international callers. A replay of the call also will be available until 11:59 p.m. (ET), Friday, March 3, 2017, by calling (877) 481-4010 in the U.S. and Canada or (919) 882-2331 internationally and entering conference ID number 10176.

About Pinnacle West Capital

Pinnacle West Capital Corp., an energy holding company based in Phoenix, has consolidated assets of about $16 billion, about 6,200 megawatts of generating capacity and 6,300 employees in Arizona and New Mexico. Through its principal subsidiary, Arizona Public Service, the Company provides retail electricity service to nearly 1.2 million Arizona homes and businesses. For more information about Pinnacle West, visit the Company’s website at pinnaclewest.com.

Earnings per share amounts are based on average diluted common shares outstanding. For more information on Pinnacle West’s operating statistics and earnings, please visit pinnaclewest.com/investors.

FORWARD-LOOKING STATEMENTS

This press release contains forward-looking statements based on our current expectations, including statements regarding our earnings guidance and financial outlook and goals. These forward-looking statements are often identified by words such as “estimate,” “predict,” “may,” “believe,” “plan,” “expect,” “require,” “intend,” “assume,” “project” and similar words. Because actual results may differ materially from expectations, we caution readers not to place undue reliance on these statements. A number of factors could cause future results to differ materially from historical results, or from outcomes currently expected or sought by Pinnacle West or APS. These factors include, but are not limited to:

• our ability to manage capital expenditures and operations and maintenance costs while maintaining high reliability and customer service levels;

• variations in demand for electricity, including those due to weather, seasonality, the general economy, customer and sales growth (or decline), and the effects of energy conservation measures and distributed generation;

• power plant and transmission system performance and outages;

• competition in retail and wholesale power markets;

• regulatory and judicial decisions, developments and proceedings;

• new legislation, ballot initiatives and regulation, including those relating to environmental requirements, regulatory policy, nuclear plant operations and potential deregulation of retail electric markets;

• fuel and water supply availability;

• our ability to achieve timely and adequate rate recovery of our costs, including returns on and of debt and equity capital investment;

• our ability to meet renewable energy and energy efficiency mandates and recover related costs;

• risks inherent in the operation of nuclear facilities, including spent fuel disposal uncertainty;

• current and future economic conditions in Arizona, including in real estate markets;

• the development of new technologies which may affect electric sales or delivery;

• the cost of debt and equity capital and the ability to access capital markets when required;

• environmental, economic and other concerns surrounding coal-fired generation, including regulation of greenhouse gas emissions;

• volatile fuel and purchased power costs;

• the investment performance of the assets of our nuclear decommissioning trust, pension, and other postretirement benefit plans and the resulting impact on future funding requirements;

• the liquidity of wholesale power markets and the use of derivative contracts in our business;

• potential shortfalls in insurance coverage;

• new accounting requirements or new interpretations of existing requirements;

• generation, transmission and distribution facility and system conditions and operating costs;

• the ability to meet the anticipated future need for additional generation and associated transmission facilities in our region;

• the willingness or ability of our counterparties, power plant participants and power plant land owners to meet contractual or other obligations or extend the rights for continued power plant operations; and

• restrictions on dividends or other provisions in our credit agreements and Arizona Corporation Commission orders.

These and other factors are discussed in Risk Factors described in Part 1, Item 1A of the Pinnacle West/APS Annual Report on Form 10-K for the fiscal year ended December 31, 2016, which readers should review carefully before placing any reliance on our financial statements or disclosures. Neither Pinnacle West nor APS assumes any obligation to update these statements, even if our internal estimates change, except as required by law.

# # #

PINNACLE WEST CAPITAL CORPORATION

CONSOLIDATED STATEMENTS OF INCOME

(unaudited)

(dollars and shares in thousands, except per share amounts)

		THREE MONTHS ENDED				TWELVE MONTHS ENDED
		DECEMBER 31,				DECEMBER 31,
		2016		2015		2016		2015
Operating Revenues		$ 739,199		$ 734,430		$ 3,498,682		$ 3,495,443
Operating Expenses
	Fuel and purchased power	243,257		232,737		1,075,510		1,101,298
	Operations and maintenance	208,277		222,019		911,319		868,377
	Depreciation and amortization	122,852		125,109		485,829		494,422
	Taxes other than income taxes	40,597		42,323		166,499		171,812
	Other expenses	1,400		2,408		3,541		4,932
	Total	616,383		624,596		2,642,698		2,640,841
Operating Income		122,816		109,834		855,984		854,602
Other Income (Deductions)
	Allowance for equity funds used during construction	11,061		9,001		42,140		35,215
	Other income	516		72		901		621
	Other expense	(3,252	)	(5,390	)	(15,337	)	(17,823	)
	Total	8,325		3,683		27,704		18,013
Interest Expense
	Interest charges	50,834		48,895		205,720		194,964
	Allowance for borrowed funds used during construction	(5,121	)	(4,203	)	(19,970	)	(16,259	)
	Total	45,713		44,692		185,750		178,705
Income Before Income Taxes		85,428		68,825		697,938		693,910
Income Taxes		27,309		22,847		236,411		237,720
Net Income		58,119		45,978		461,527		456,190
Less: Net income attributable to noncontrolling interests		4,873		4,861		19,493		18,933
Net Income Attributable To Common Shareholders		$ 53,246		$ 41,117		$ 442,034		$ 437,257
Weighted-Average Common Shares Outstanding - Basic		111,545		111,149		111,409		111,026
Weighted-Average Common Shares Outstanding - Diluted		112,223		111,738		112,046		111,552
Earnings Per Weighted-Average Common Share Outstanding
	Net income attributable to common shareholders - basic	$ 0.48		$ 0.37		$ 3.97		$ 3.94
	Net income attributable to common shareholders - diluted	$ 0.47		$ 0.37		$ 3.95		$ 3.92

EX-99.2

Fourth Quarter and Full-Year 2016 FOURTH QUARTER AND FULL-YEAR 2016 RESULTS February 24, 2017

Fourth Quarter and Full-Year 20162 FORWARD LOOKING STATEMENTS AND NON-GAAP FINANCIAL MEASURES This presentation contains forward-looking statements based on current expectations, including statements regarding our earnings guidance and financial outlook and goals. These forward-looking statements are often identified by words such as “estimate,” “predict,” “may,” “believe,” “plan,” “expect,” “require,” “intend,” “assume,” “project” and similar words. Because actual results may differ materially from expectations, we caution you not to place undue reliance on these statements. A number of factors could cause future results to differ materially from historical results, or from outcomes currently expected or sought by Pinnacle West or APS. These factors include, but are not limited to: our ability to manage capital expenditures and operations and maintenance costs while maintaining high reliability and customer service levels; variations in demand for electricity, including those due to weather seasonality, the general economy, customer and sales growth (or decline), and the effects of energy conservation measures and distributed generation; power plant and transmission system performance and outages; competition in retail and wholesale power markets; regulatory and judicial decisions, developments and proceedings; new legislation, ballet initiatives and regulation, including those relating to environmental requirements, regulatory policy, nuclear plant operations and potential deregulation of retail electric markets; fuel and water supply availability; our ability to achieve timely and adequate rate recovery of our costs, including returns on and of debt and equity capital investments; our ability to meet renewable energy and energy efficiency mandates and recover related costs; risks inherent in the operation of nuclear facilities, including spent fuel disposal uncertainty; current and future economic conditions in Arizona, including in real estate markets; the development of new technologies which may affect electric sales or delivery; the cost of debt and equity capital and the ability to access capital markets when required; environmental, economic and other concerns surrounding coal-fired generation, including regulation of greenhouse gas emissions; volatile fuel and purchased power costs; the investment performance of the assets of our nuclear decommissioning trust, pension, and other postretirement benefit plans and the resulting impact on future funding requirements; the liquidity of wholesale power markets and the use of derivative contracts in our business; potential shortfalls in insurance coverage; new accounting requirements or new interpretations of existing requirements; generation, transmission and distribution facility and system conditions and operating costs; the ability to meet the anticipated future need for additional generation and associated transmission facilities in our region; the willingness or ability of our counterparties, power plant participants and power plant land owners to meet contractual or other obligations or extend the rights for continued power plant operations; and restrictions on dividends or other provisions in our credit agreements and ACC orders. These and other factors are discussed in Risk Factors described in Part I, Item 1A of the Pinnacle West/APS Annual Report on Form 10-K for the fiscal year ended December 31, 2016, which you should review carefully before placing any reliance on our financial statements, disclosures or earnings outlook. Neither Pinnacle West nor APS assumes any obligation to update these statements, even if our internal estimates change, except as required by law. In this presentation, references to net income and earnings per share (EPS) refer to amounts attributable to common shareholders. We present “gross margin” per diluted share of common stock. Gross margin refers to operating revenues less fuel and purchased power expenses. Gross margin is a “non-GAAP financial measure,” as defined in accordance with SEC rules. The appendix contains a reconciliation of this non-GAAP financial measure to the referenced revenue and expense line items on our Consolidated Statements of Income, which are the most directly comparable financial measures calculated and presented in accordance with generally accepted accounting principles in the United States of America (GAAP). We view gross margin as an important performance measure of the core profitability of our operations. We refer to “on-going earnings” in this presentation, which is also a non-GAAP financial measure. We also provide a reconciliation to show the impacts associated with certain regulatory adjustments. We believe on-going earnings and these adjustments included in the reconciliation provide investors with a useful indicator of our results that is comparable among periods because it excludes the effects of unusual items that may occur on an irregular basis. Investors should note that these non-GAAP financial measures may involve judgments by management, including whether an item is classified as an unusual item. These measures are key components of our internal financial reporting and are used by our management in analyzing the operations of our business. We believe that investors benefit from having access to the same financial measures that management uses.

Fourth Quarter and Full-Year 20163 CONSOLIDATED EPS COMPARISON 2016 VS. 2015 $0.47 $0.37 2016 2015 4th Quarter GAAP Net Income $0.47 $0.37 4th Quarter On-Going Earnings $3.95 $3.92 2016 2015 Full-Year GAAP Net Income $3.95 $3.92 Full-Year On-Going Earnings

Fourth Quarter and Full-Year 20164 O&M(1) $0.06 ON-GOING EPS VARIANCES 4TH QUARTER 2016 VS. 4TH QUARTER 2015 Interest, net of AFUDC $0.01 4Q 2015 4Q 2016 Gross Margin(1),(2) Sales $ (0.03) LFCR $ 0.03 Transmission $ (0.01) Other $ 0.01 $0.37 $0.47 D&A(2) $(0.01) Other, net $0.03Other Taxes $0.01 (1) Excludes costs and offsetting operating revenues, associated with renewable energy (excluding AZ Sun) and demand side management programs. (2) Excludes revenues and offsetting depreciation and amortization expense related to reduced Palo Verde system benefits charge. See non-GAAP reconciliation.

Fourth Quarter and Full-Year 20165 Gross Margin(1), (2) $0.33 ON-GOING EPS VARIANCES FULL YEAR 2016 VS. 2015 O&M(1) $(0.30) D&A(2) $(0.03) Other, net $(0.02) Interest, net of AFUDC $0.02 $3.92 $3.95 2015 2016 Other Taxes $0.03 Gross Margin Weather $ 0.02 Sales $ 0.05 LFCR $ 0.09 Transmission $ 0.08 Transmission Line Sale $ 0.03 AZ Sun $ 0.01 Other $ 0.05 (1) Excludes costs and offsetting operating revenues, associated with renewable energy (excluding AZ Sun) and demand side management programs. (2) Excludes revenues and offsetting depreciation and amortization expense related to reduced Palo Verde system benefits charge. See non-GAAP reconciliation.

Fourth Quarter and Full-Year 20166 0 10,000 20,000 30,000 40,000 '07 '08 '09 '10 '11 '12 '13 '14 '15 '16 '17 Single Family Multifamily ECONOMIC INDICATORS Arizona and Metro Phoenix remain attractive places to live and do business Single Family & Multifamily Housing Permits Maricopa County Above-average job growth in construction and financial services Metro Phoenix growth rate 3rd fastest among top 15 metro areas - U.S. Census Bureau March 2016 E Scottsdale ranked best place in the U.S. to find a new job in 2017; 4 other valley cities ranked in Top 20 - WalletHub January 2017 Housing construction on pace to have its best year since 2007 Vacancy rates in office and retail space have fallen to pre-recessionary levels Nonresidential Net Absorption – Metro Phoenix (2) (1) - 1 2 3 4 5 '10 '11 '12 '13 '14 '15 '16 Millions Sq. Ft Office Retail

Fourth Quarter and Full-Year 2016 APPENDIX

Fourth Quarter and Full-Year 20168 2017 KEY DATES ACC Key Dates / Docket # Q1 Q2 Q3 Q4 Key Recurring Regulatory Filings Lost Fixed Cost Recovery E-01345A-11-0224 Jan 15 Transmission Cost Adjustor E-01345A-11-0224 May 15 2018 DSM/EE Implementation Plan Jun 1 2018 RES Implementation Plan for Reset of Renewable Energy Adjustor Jul 1 APS Rate Case E-01345A-16-0036 --------------- See Slide 10 --------------- Resource Planning and Procurement E-00000V-15-0094 April 3: Final IRP due Reducing System Peak Demand Costs E-00000J-16-0257 --------------- TBD --------------- Review, Modernization and Expansion of Arizona Renewable Energy Standards E-00000Q-16-0289 --------------- TBD --------------- ACC Open Meetings ACC Open Meetings Held Monthly * April 2017: Final IRP due Other Key Dates Q1 Q2 Q3 Q4 Arizona State Legislature In session Jan 9 – End of Q2

Fourth Quarter and Full-Year 20169 2016 APS RATE CASE Procedural Schedule Staff and Intervenor Direct Testimony (ex rate design) Staff and Intervenor Direct Testimony (Rate Design) APS Rebuttal Testimony Staff Resource Comparison Proxy (RCP) Direct Testimony Settlement Deadline APS and Intervener RCP Rebuttal Testimony Staff and Intervenor Surrebuttal Testimony Prehearing Conference Proposed Hearing Commencement Date December 28, 2016 February 3, 2017 February 24, 2017 March 10, 2017 March 17, 2017 March 31, 2017 April 14, 2017 April 20, 2017 April 24, 2017 • Filed June 1, 2016 • Propose new rates go into effect on July 1, 2017 • Docket Number: E-01345A-16-0036 • Additional details, including filing, can be found at http://www.azenergyfuture.com/rate-review/

Fourth Quarter and Full-Year 201610 ARIZONA ELECTRIC UTILITIES GENERAL RATE CASES UNS Electric (93,000 customers) Docket # E-04204A-15-0142 Application Filed May 5, 2015 Hearing (Mar 1 – 24, 2016) Phase One Decision (Decision No. 75697, Aug 18, 2016) UNSE Customer Education Plan on Rates : Filed Sep 30, 2016 Final Non-DG Rates Approved: Feb 8, 2017 Phase Two (Net Metering Issues) Testimony: Mar – Jun 2017 Phase Two Hearing: Begins June 28, 2017 Phase Two Decision: Expected Oct 2017 Tucson Electric Power Company (415,000 customers) Docket # E-01933A-15-0322 Application Filed Nov 5, 2015 Non-unanimous Revenue Requirement Settlement Filed (Aug 15, 2016) Hearing (Sep 8 – 20, 2016) Phase One Decision: Feb 9, 2017 Phase Two (Net Metering Issues) Testimony: Mar – Jun 2017 Phase Two Hearing : Begins Jun 28, 2017 Phase Two Decision: Expected Oct 2017 Sulphur Springs Valley Electric Cooperative (58,000 customers) Docket # E-01575A-15-0312 Application Filed Aug 31, 2015 Hearing (May 17 – 27 , 2016) Decision in Phase One (Decision No. 75788, Nov 11, 2016) Phase Two (Net Metering Issues) Testimony: Apr – Jun 2017 Phase Two Hearing: Begins Jul 20, 2017 Phase Two Decision: Expected Nov 2017 Trico Electric Cooperative (38,000 customers) Docket # E-01461A-15-0363 Application Filed Oct 23, 2015 Non-unanimous Revenue Requirement Settlement (Jul 8, 2016) Hearing (Aug 17, 2016) Decision: Feb 9, 2017 No Phase Two Proceeding Necessary

Fourth Quarter and Full-Year 201611 2017 ON-GOING EARNINGS KEY DRIVERS • EPS guidance issuance pending timing and outcome of APS rate case • Retail customer growth about 1.5-2.5% • Weather-normalized retail electricity sales volume growth about 0.0-1.0% after customer conservation and energy efficiency and distributed renewable generation • Transmission rate increase • Operations and maintenance - Planned outages (e.g. Four Corners SCRs) • Depreciation and amortization - Higher plant balances • Interest rates • AFUDC

Fourth Quarter and Full-Year 201612 FINANCIAL OUTLOOK Key Factors & Assumptions as of February 24, 2017 Assumption Impact Retail customer growth • Projected to average in the range of about 2-3% • Modestly improving Arizona and U.S. economic conditions Weather-normalized retail electricity sales volume growth • About 0.5-1.5% after customer conservation and energy efficiency and distributed renewable generation initiatives Assumption Impact AZ Sun Program • Additions to flow through RES until next base rate case • First 50 MW of AZ Sun is recovered through base rates Lost Fixed Cost Recovery (LFCR) • Offsets 30-40% of revenues lost due to ACC-mandated energy efficiency and distributed renewable generation initiatives Environmental Improvement Surcharge (EIS) • Assumed to recover up to $5 million annually of carrying costs for government-mandated environmental capital expenditures Power Supply Adjustor (PSA) • 100% recovery as of July 1, 2012 Transmission Cost Adjustor (TCA) • TCA is filed each May and automatically goes into rates effective June 1 • Beginning July 1, 2012 following conclusion of the regulatory settlement, transmission revenue is accrued each month as it is earned. Four Corners Acquisition • Four Corners rate increase effective January 1, 2015 Potential Property Tax Deferrals (2012 retail rate settlement): Assume 60% of property tax increases relate to tax rates, therefore, will be eligible for deferrals (Deferral rates: 50% in 2013; 75% in 2014 and thereafter) Gross Margin – Customer Growth and Weather (2017-2019) Gross Margin – Related to 2012 Retail Rate Settlement

Fourth Quarter and Full-Year 201613 RATE BASE APS’s revenues come from a regulated retail rate base and meaningful transmission business $6.5 $8.3 $1.4 $1.8 2015 2016* 2017 2018 2019 APS Rate Base Growth Year-End ACC FERC Total Rate Base Projected Most Recent Rate Decisions ACC - Proposed FERC Rate Effective Date 7/1/2017 6/1/2016 Test Year Ended 12/31/20151 12/31/2015 Rate Base $6.8B $1.4B Equity Layer 56% 56% Allowed ROE 10.5% 10.75% 1 Adjusted to include post test-year plant in service through 6/30/2017 83% 17% Generation & Distribution Transmission *2016 rate base pending update following FERC Form 1 filing Rate base $ in billions, rounded

Fourth Quarter and Full-Year 201614 $221 $219 $284 $214 $79 $237 $119 $8 $220 $195 $105 $61 $102 $4 $1 $127 $206 $137 $150 $388 $402 $406 $480 $87 $74 $72 $81 2016 2017 2018 2019 APS CAPITAL EXPENDITURES Capital expenditures are funded primarily through internally generated cash flow ($ Millions) $1,224 $1,337 Other Distribution Transmission Renewable Generation Environmental(1) Traditional Generation Projected $1,124 New Gas Generation(2) • The table does not include capital expenditures related to 4CA’s 7% interest in Four Corners Units 4 and 5 of $30 million in 2016, $27 million in 2017, $15 million in 2018 and $6 million in 2019. • 2017 – 2019 as disclosed in 2016 Form 10-K. (1) Includes Selective Catalytic Reduction controls at Four Corners with in-service dates of Q4 2017 (Unit 5) and Q1 2018 (Unit 4) (2) Ocotillo Modernization Project: 2 units scheduled for completion in Q4 2018, 3 units scheduled for completion in Q1 2019 $994

Fourth Quarter and Full-Year 201615 OPERATIONS & MAINTENANCE Goal is to keep O&M per kWh flat, adjusted for planned outages $754 $761 $788 $805 $772 $828 $150 $124 $137 $103 $96 $83 2011 2012 2013 2014 2015 2016 PNW Consolidated RES/DSM* *Renewable energy and demand side management expenses are offset by adjustment mechanisms. ($ Millions)

Fourth Quarter and Full-Year 201616 Credit Ratings • A- rating or better at S&P, Moody’s and Fitch 2016 Major Financing Activities • $100 million 3-year term loan closed April 2016 • $350 million 30-year 3.75% APS senior unsecured notes issued May 2016 • $250 million 10-year 2.55% APS senior unsecured notes issued September 2016 2017 Major Financing Activities • Currently expect up to $850 million of long-term debt, including refinance of $125 million PNW term loan We are disclosing credit ratings to enhance understanding of our sources of liquidity and the effects of our ratings on our costs of funds. BALANCE SHEET STRENGTH $50 $600 $250 $125 $- $100 $200 $300 $400 $500 $600 2017 2018 2019 2020 APS PNW ($Millions) Debt Maturity Schedule

Fourth Quarter and Full-Year 201617 • Funded status of the pension plan finished 2016 at 88%, unchanged from YE 2015. • The pension plan continues to employ a liability driven investment strategy in order to reduce volatility in the plan’s funded status. PENSION & OTHER POST RETIREMENT BENEFITS (“OPEB”) 90% 88% 88% YE 2014 YE 2015 YE 2016 Pension Funded Status(1) Expense(2) 2016A 2017E Pension(1) $19 $24 OPEB ($12) ($19) Contributions 2016A 2017E 2018E 2019E Pension $100 $100 Up to $100 Up to $100 OPEB $0.8 $0.4 $0.0 $0.0 Expense Assumptions 2016 2017 Discount Rate: Pension 4.37% 4.08% Expected Long-Term Return on Plan Assets: Pension 6.90% 6.55% (1) Excludes supplemental excess benefit retirement plan calculated on a PBO basis. (2) Excludes approximately 50% of total estimated expense which is attributable to amounts capitalized or billed to electric generating plant joint owners. Data as of February 24, 2017 ($ in millions)

Fourth Quarter and Full-Year 201618 249 357 339 442 610 710 641 783 871 939 523 836 0 250 500 750 1000 1250 1500 1750 2000 2250 2500 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2014 Applications 2015 Applications 2016 Applications 2017 Applications * Monthly data equals applications received minus cancelled applications. As of January 31, 2017 approximately 55,000 residential grid-tied solar photovoltaic (PV) systems have been installed in APS’s service territory, totaling more than 420 MWdc of installed capacity. Excludes APS Solar Partner Program residential PV systems. Note: www.arizonagoessolar.org logs total residential application volume, including cancellations. Solar water heaters can also be found on the site, but are not included in the chart above. RESIDENTIAL PV APPLICATIONS* 10 18 22 44 51 57 74 133 12 2009 2011 2013 2015 2017 Residential DG (MWdc) Annual Additions

Fourth Quarter and Full-Year 201619 (8) (4) (1) 4 (5) 13 (17) 4 $(20) $(15) $(10) $(5) $0 $5 $10 $15 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 GROSS MARGIN EFFECTS OF WEATHER VARIANCES VS. NORMAL Pretax Millions All periods recalculated to current 10-year rolling average (2005-2014) 2015 $(8) Million 2016 $(5) Million

Fourth Quarter and Full-Year 201620 12 7 11 11 8 4 7 6 11 14 18 12 12 15 18 13 $0 $10 $20 $30 $40 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Renewable Energy Demand Side Management RENEWABLE ENERGY AND DEMAND SIDE MANAGEMENT EXPENSES* * O&M expenses related to renewable energy and demand side management programs are partially offset by comparable revenue amounts Pretax Millions 2015 $96 Million 2016 $83 Million

Fourth Quarter and Full-Year 201621 NON-GAAP MEASURE RECONCILIATION $ millions pretax, except per share amounts 2016 2015 Operating revenues* 739$ 734$ Fuel and purchased power expenses* (243) (232) Gross margin 496 502 (0.03)$ Adjustments: Renewable energy (excluding AZ Sun) and demand side management programs (14) (18) 0.02 Palo Verde system benefits charge 2 - 0.01 Adjusted gross margin 484$ 484$ -$ Depreciation and amortization* (123)$ (125)$ 0.01$ Adjustments: Palo Verde system benefits charge - (4) 0.02 Adjusted depreciation and amortization 123$ (121)$ (0.01)$ * Line items from Consolidated Statements of Income Three Months Ended December 31, EPS Impact

Fourth Quarter and Full-Year 201622 NON-GAAP MEASURE RECONCILIATION $ millions pretax, except per share amounts 2016 2015 Operating revenues* 3,499$ 3,495$ Fuel and purchased power expenses* (1,076) (1,101) Gross margin 2,423 2,394 0.16$ Adjustments: Renewable energy (excluding AZ Sun) and demand side management programs (61) (78) 0.09 Palo Verde system benefits charge 14 - 0.08 Adjusted gross margin 2,376$ 2,316$ 0.33$ Depreciation and amortization* (486)$ (494)$ 0.05$ Adjustments: Palo Verde system benefits charge (2) (16) 0.08 Adjusted depreciation and amortization (484)$ (478)$ (0.03)$ * Line items from Consolidated Statements of Income Twelve Months Ended December 31, EPS Impact

Fourth Quarter and Full-Year 201623 CONSOLIDATED STATISTICS 2016 2015 Incr (Decr) 2016 2015 Incr (Decr) ELECTRIC OPERATING REVENUES (Dollars in Millions) Retail Residential 332$ 328$ 4$ 1,730$ 1,702$ 28$ Business 362 349 13 1,605 1,584 21 Total Retail 694 677 17 3,335 3,286 49 Sales for Resale (Wholesale) 30 40 (10) 95 149 (54) Transmission for Others 7 7 - 28 34 (6) Other Miscellaneous Services 6 10 (4) 32 23 9 Total Electric Operating Revenues 737$ 734$ 3$ 3,490$ 3,492$ (2)$ ELECTRIC SALES (GWH) Retail Residential 2,671 2,767 (96) 13,195 13,160 35 Business 3,460 3,445 15 14,827 14,791 36 Total Retail 6,131 6,212 (81) 28,022 27,951 71 Sales for Resale (Wholesale) 1,045 2,357 (1,312) 3,767 6,340 (2,573) Total Electric Sales 7,176 8,569 (1,393) 31,789 34,291 (2,502) RETAIL SALES (GWH) - WEATHER NORMALIZED Residential 2,648 2,727 (79) 13,297 13,366 (69) Business 3,431 3,417 14 14,766 14,695 71 Total Retail Sales 6,079 6,144 (65) 28,063 28,061 2 Retail sales (GWH) (% over prior year) (1.1)% - AVERAGE ELECTRIC CUSTOMERS Retail Customers Residential 1,066,711 1,053,177 13,534 1,061,814 1,046,990 14,824 Business 132,173 130,846 1,327 131,697 130,505 1,192 Total Retail 1,198,884 1,184,023 14,861 1,193,511 1,177,495 16,016 Wholesale Customers 46 47 (1) 46 47 (1) Total Customers 1,198,930 1,184,070 14,860 1,193,557 1,177,542 16,015 Total Customer Growth (% over prior year) 1.3% 1.4% RETAIL USAGE - WEATHER NORMALIZED (KWh/Average Customer) Residential 2,482 2,589 (107) 12,523 12,766 (243) Business 25,960 26,118 (158) 112,120 112,602 (482) 3 Months Ended December 31, 12 Months Ended December 31,

Fourth Quarter and Full-Year 201624 CONSOLIDATED STATISTICS 2016 2015 Incr (Decr) 2016 2015 Incr (Decr) WEATHER INDICATORS - RESIDENTIAL Actual Cooling Degree-Days 57 73 (16) 1,720 1,822 (102) Heating Degree-Days 282 463 (181) 679 717 (38) Average Humidity 29% 41% (12)% 27% 31% (4)% 10-Year Averages (2005 - 2014) Cooling Degree-Days 41 41 - 1,768 1,768 - Heating Degree-Days 346 346 - 835 835 - Average Humidity 27% 27% - 25% 25% - ENERGY SOURCES (GWH) Generation Production Nuclear 2,276 2,202 74 9,384 9,464 (80) Coal 2,376 2,621 (245) 6,687 10,921 (4,233) Gas, Oil and Other 1,508 1,988 (480) 8,270 6,573 1,697 Renewables 93 106 (13) 397 529 (132) Total Generation Production 6,252 6,916 (664) 24,738 27,487 (2,748) Purchased Power - - Conventional 753 941 (188) 5,737 5,614 123 Resales 188 83 105 785 380 404 Renewables 430 454 (24) 1,825 1,794 31 Total Purchased Power 1,371 1,478 (107) 8,346 7,788 558 Total Energy Sources 7,624 8,394 (771) 33,084 35,274 (2,190) POWER PLANT PERFORMANCE Capacity Factors - Owned Nuclear 90% 87% 3% 93% 94% (1)% Coal 36% 71% (35)% 46% 74% (29)% Gas, Oil and Other 31% 27% 4% 28% 22% 6% Solar 22% 25% (3)% 24% 23% 1% System Average 46% 51% (5)% 45% 50% (5)% 3 Months Ended December 31, 12 Months Ended December 31,