Regulated Operations	9 Months Ended
Sep. 30, 2022
Regulated Operations [Abstract]
Rate Matters and Regulation	Rate Matters and Regulation Except as set forth below, the circumstances set forth in Note 16 to the financial statements included in the Registrants' 2021 Form 10-K appropriately represent, in all material respects, the current status of the Registrants' regulatory matters. Completed Regulatory Matters APSC Proceedings Arkansas 2021 Formula Rate Plan Filing In October 2021, OG&E filed its fourth evaluation report under its Formula Rate Plan, and on February 1, 2022, OG&E, the APSC General Staff and the Office of the Arkansas Attorney General filed a non-unanimous joint settlement agreement, which included an annual electric revenue increase of $4.2 million. The only non-signatory to the settlement agreement agreed not to oppose the settlement. On March 4, 2022, the APSC issued a final order approving the non-unanimous settlement agreement, and new rates became effective April 1, 2022. OCC Proceedings Winter Storm Uri In December 2021, the OCC approved a settlement agreement in a final financing order authorizing the issuance of securitization bonds in an amount up to $760.0 million, which included estimated finance costs and was subject to change for carrying costs, any updates from the SPP settlement process and actual securitization issuance costs. On July 20, 2022, the ODFA issued the securitization bonds consistent with the OCC's order. In connection with the securitization transaction, the ODFA and OG&E entered into an agreement on July 20, 2022 whereby the ODFA purchased, and OG&E sold, the securitization property that was created pursuant to legislation enacted by the State of Oklahoma in April 2021 and the financing order received from the OCC in December 2021. Such securitization property includes the right to assess, impose, adjust, collect and receive funds, in the form of the winter event securitization charge, from OG&E's existing and future Oklahoma customers in amounts intended to be sufficient to pay the principal and interest and financing charges on the securitization bonds. On July 20, 2022, OG&E received proceeds of approximately $750 million for the sale of the securitization property, which represented the amount of the securitization bonds sold less the issuance costs. OG&E used these proceeds to fund the Oklahoma Winter Storm Uri regulatory asset by recovering the authorized extreme, extraordinary fuel and purchased power costs incurred during Winter Storm Uri, as well as carrying costs. Beginning August 1, 2022, OG&E acts as a servicer for collecting the funds from Oklahoma customers that are then submitted to the ODFA to repay the securitization bonds over 28 years. 2021 Oklahoma General Rate Review In December 2021, OG&E filed a general rate review in Oklahoma seeking a rate increase of $163.5 million and a 10.2 percent return on equity based on a common equity percentage of 53.37 percent. The rate review was based on a September 30, 2021 test year and included a request for recovery of $1.2 billion of capital investment since the last general rate review. OG&E had the right to implement interim rates subject to refund beginning July 1, 2022 (180 days after the filing of its application on December 30, 2021). On July 1, 2022, OG&E implemented an annual interim rate increase of $30.0 million, subject to refund for amounts in excess of the rates approved by the OCC. On September 8, 2022, the OCC approved a Joint Stipulation and Settlement Agreement that had been entered into by OG&E, the OCC Public Utility Division Staff, the Oklahoma Attorney General, the OG&E Shareholders Association, Oklahoma Industrial Energy Consumers and other intervenors. Non-signatory parties had agreed not to contest this agreement. Key terms of the agreement, as approved by the OCC, include, among others: •A base rate revenue increase of $30.0 million; •OG&E would issue a refund, over a 12-month period, for the tax expense savings arising from the reduction in the Oklahoma state corporate income tax rate from 6 percent to 4 percent for the period from January 1, 2022 through June 30, 2022, as well as amortize over five years the excess accumulated deferred income tax balance resulting from this corporate tax rate change; •There would be no change in OG&E's current return on equity of 9.5 percent, and OG&E's requested capital structure based on a common equity percentage of 53.37 percent would be approved; •OG&E would utilize depreciation rates based on the recommendations of the Oklahoma Attorney General with the exception of transmission and general plant accounts, which would be based on the depreciation rates recommended by the Oklahoma Industrial Energy Consumers; •OG&E's Grid Enhancement Plan projects recorded as of March 31, 2022 would be considered prudent and be included in base rates; •OG&E's Grid Enhancement Plan interim recovery would continue and updated terms include: (i) cost recovery through a rider mechanism will be limited to projects placed in service in 2022, 2023 and 2024, capped at a revenue requirement of $6.0 million for each annual investment plan and include communication, automation and technology systems projects, as well as certain weather hardening projects; and (ii) the rider mechanism will terminate by the issuance of a final order in OG&E's first general rate review following completion of projects included in the 2024 annual investment plan or no later than July 1, 2025; •OG&E would amend several of its rider tariffs to incorporate the agreements of the stipulating parties; and •Regulatory accounting treatments approved include, among other things, the establishment of a regulatory asset to defer operation and maintenance costs associated with OG&E's SAP S/4 HANA enterprise resource planning system project for consideration in future rate proceedings with the carrying cost accruing at OG&E's short-term cost of debt, the amortization of COVID-19 regulatory asset balance over five years and the amortization of over/under-recovery balance of the pension tracker over 15 years, which is a change from the previous five-year recovery period. Due to the September 8, 2022 OCC approval of the rate increase of $30.0 million, no refund of interim rates was necessary. Pending Regulatory Matters Various proceedings pending before state or federal regulatory agencies are described below. Unless stated otherwise, the Registrants cannot predict when the regulatory agency will act or what action the regulatory agency will take. The Registrants' financial results are dependent in part on timely and constructive decisions by the regulatory agencies that set OG&E's rates. FERC Proceedings Order for Sponsored Transmission Upgrades within SPP Under the SPP Open Access Transmission Tariff, costs of participant-funded, or "sponsored," transmission upgrades may be recovered from other SPP customers whose transmission service depends on capacity enabled by the upgrade. The SPP Open Access Transmission Tariff required the SPP to charge for these upgrades beginning in 2008, but the SPP had not been charging its customers for these upgrades due to information system limitations. However, the SPP had informed participants in the market that these charges would be forthcoming. In July 2016, the FERC granted the SPP's request to recover the charges not billed since 2008. The SPP subsequently billed OG&E for these charges and credited OG&E related to transmission upgrades that OG&E had sponsored, which resulted in OG&E being a net receiver of sponsored upgrade credits. The majority of these net credits were refunded to customers through OG&E's various rate riders that include SPP activity with the remaining amounts retained by OG&E. Several companies that were net payers of Z2 charges sought rehearing of the FERC's July 2016 order; however, in November 2017, the FERC denied the rehearing requests. In January 2018, one of the impacted companies appealed the FERC's decision to the U.S. Court of Appeals for the District of Columbia Circuit. In July 2018, that court granted a motion requested by the FERC that the case be remanded back to the FERC for further examination and proceedings. In February 2019, the FERC reversed its July 2016 order and November 2017 rehearing denial, ruled that the SPP violated its tariff to charge for the 2008 through 2015 period in 2016, held that the SPP tariff provision that prohibited those charges could not be waived and ordered the SPP to develop a plan to refund the payments but not to implement the refunds until further ordered to do so. In response, in April 2019, OG&E filed a request for rehearing with the FERC, and in May 2019, OG&E filed a FERC 206 complaint against the SPP, alleging that the SPP's forced unwinding of the revenue credit payments to OG&E would violate the provisions of the Sponsored Upgrade Agreement and of the applicable tariff. OG&E's filing requested that the FERC rule that the SPP is not entitled to seek refunds or in any other way seek to unwind the revenue credit payments it had paid to OG&E pursuant to the Sponsored Upgrade Agreement. The SPP's response to OG&E's filing agreed that OG&E should be entitled to keep its Z2 payments and argued that the SPP should not be held responsible for those payments if refunds are ordered. Further, the SPP has requested the FERC to negotiate a global settlement with all impacted parties, including other project sponsors who, like OG&E, have also filed complaints at FERC contending that the payments they have received cannot properly be unwound. In February 2020, the FERC denied OG&E's request for rehearing of its February 2019 order, denying the waiver and ruling that the SPP must seek refunds from project sponsors for Z2 payments for the 2008 through 2015 period and pay them back to transmission owners. The FERC also denied the SPP's request for a stay and for institution of settlement procedures. The FERC stated it would not institute settlement procedures unless parties on both sides of the matter requested them. The FERC did not rule on OG&E's complaint or the complaints of other project sponsors, or consider the SPP's refund plan. The FERC thus has not set any date for payment of refunds. In March 2020, OG&E petitioned the U.S. Court of Appeals for the District of Columbia Circuit for review of the FERC's order denying the waiver and requiring refunds. The court issued a decision on August 27, 2021, denying review and holding that the SPP was prohibited by the filed rate doctrine from imposing Z2 charges during the 2008 through 2015 historical period. The court further held that the FERC reasonably exercised its remedial authority to order the SPP to refund the retroactive upgrade charge. The court did not direct a time frame or procedures for the SPP to implement refunds. OG&E and the SPP filed a petition for rehearing of the court's decision, which was denied in October 2021. The court returned the matter to the FERC for action in accordance with its opinion in November 2021. If the FERC proceeds to order refunds in full, OG&E estimates it would be required to refund $13.0 million, which is net of amounts paid to other utilities for upgrades and would be subject to interest at the FERC-approved rate. The SPP has stated in filings it made with the FERC while the appeal was pending that there are considerable complexities in implementing the refunds that will have to be resolved before they can be paid. Payment of refunds would shift recovery of these upgrade credits to future periods. The SPP filed an update on January 4, 2022 confirming that administering refunds would be complex and could take years unless the SPP is allowed to make certain simplifying assumptions. It also urged that all pending complaint proceedings, including four complaints against the SPP, be resolved before the refund process is ordered to begin. OG&E and other parties filed responses to the SPP report, and the matter remains pending at the FERC. Of the $13.0 million, the Registrants would be impacted by $5.0 million in expense that initially benefited the Registrants in 2016, and OG&E customers would incur a net impact of $8.0 million in expense through rider mechanisms or the FERC formula rate. As of September 30, 2022, the Registrants have reserved $13.0 million plus estimated interest for a potential refund. In January 2020, the FERC acted on an SPP proposal to eliminate Attachment Z2 revenue crediting and replace it with a different rate mechanism that would provide project sponsors, such as OG&E, the same level of recovery, and rejected the proposal to the extent it would limit recovery to the amount of the upgrade sponsor's directly assigned upgrade costs with interest. The SPP resubmitted a proposal in April 2020 without this limited recovery, and with the alternative rate mechanism, and the FERC approved it in June 2020, effective July 1, 2020. No party sought rehearing of the order, and it is now final. This order would only prospectively impact OG&E and its recovery of any future upgrade costs that it may incur as a project sponsor subsequent to July 2020. All of the existing projects that are eligible to receive revenue credits under Attachment Z2, which includes the $13.0 million at issue in OG&E's appeal as discussed above, will continue to do so. Incentive Adders for Transmission Rates The FERC issued a NOPR in March 2020, and issued a supplemental NOPR in April 2021, proposing to update its transmission incentives policy. Among other things, the NOPR proposes (i) the current 50-basis point return on equity adder for RTO/ISO participation would be applicable only to transmitting utilities that join an RTO/ISO, and this incentive would only apply for the first three years in which the utility is an RTO/ISO member and (ii) transmitting utilities that have been members of an RTO/ISO for three years or more, such as OG&E, would be required to make a compliance filing to remove the existing return on equity adder from their rates. Currently, there is no specific deadline for the FERC to take further action, and it is unknown whether the FERC will address the RTO participation adder individually or as part of a larger order on transmission incentives. APSC Proceedings Winter Storm Uri In February 2021, Winter Storm Uri resulted in record winter peak demand for electricity and extremely high natural gas and purchased power prices in OG&E's service territory. On April 1, 2021, OG&E filed with the APSC a Motion for Authority to Establish Special Regulatory Treatment within the Energy Cost Recovery Rider to Defer Extraordinary Fuel Costs Incurred Due to Winter Storm Uri. More specifically, OG&E's motion sought approval to defer, amortize and recover the extraordinary fuel costs over a ten-year period with a carrying charge of OG&E's pre-tax rate of return of 6.60 percent, through a special factor within OG&E's Energy Cost Recovery Rider beginning with the first billing cycle of May 2021. On April 13, 2021, the APSC issued an order allowing OG&E interim recovery at an interest rate equal to the customer deposit interest rate, which is currently 0.8 percent, over a period of ten years beginning with the first billing cycle of May 2021. Recovery is subject to a true-up after the APSC determines the appropriate allocation, length of recovery and carrying charge. On May 4, 2021, OG&E filed testimony further supporting its 10-year amortization period and a carrying charge of OG&E's pre-tax rate of return of 6.60 percent. In April 2021, Arkansas enacted legislation to amend its storm recovery securitization statute to allow for both electric and gas utilities to recover through securitization extraordinary natural gas, fuel and purchased power costs caused by storms. In May 2021, the APSC approved OG&E's motion for suspension of procedural schedule to investigate and evaluate the potential securitization recovery of the Arkansas jurisdictional portion of the Winter Storm Uri costs. On July 5, 2022, OG&E filed a motion to request recovery of the regulatory asset balance over 10 years using a weighted average cost of capital instead of through securitization. On July 15, 2022, the APSC Staff filed a response to OG&E’s motion stating the Staff does not oppose OG&E's request for recovery using a weighted average cost of capital, as long as no other party to the case opposes. Subsequently, other intervenors have filed their opposition to OG&E using a weighted average cost of capital for recovery. On August 1, 2022, the APSC issued a procedural order to set a schedule for additional testimony, and a hearing on the merits is expected to be held on December 2, 2022. As of September 30, 2022, OG&E has deferred $80.6 million to a regulatory asset, as indicated in Note 1. Arkansas 2021 Formula Rate Plan Filing - Extension On May 18, 2022, the APSC issued an order granting OG&E's request for a five-year extension of the Formula Rate Plan Rider with certain terms and conditions, including continuation of OG&E's current return on equity of 9.5 percent and a change to OG&E's current debt-to-equity ratio of 50/50 percent to 55/45 percent. On June 17, 2022, OG&E filed a request for rehearing seeking reconsideration by the APSC of their decision to alter the Formula Rate Plan Rider's capital structure. On September 19, 2022, the APSC issued an order reversing its May 18, 2022 order and denying the extension of OG&E's Formula Rate Plan Rider. On September 20, 2022, the APSC Staff filed a motion for clarification for the extension denial, and OG&E, the Arkansas Attorney General and Arkansas River Valley Energy Consumers filed responses to the clarification. On September 30, 2022, the APSC issued an order clarifying that OG&E is authorized to file its 2022 and 2023 evaluation reports under the Formula Rate Plan Rider to true-up prior projected year rate adjustments. On October 28, 2022, Arkansas River Valley Energy Consumers and Walmart Inc. filed a request for rehearing of the APSC's September 30, 2022 order and asked the APSC to reverse its position and prohibit OG&E from making any further filings under its current Formula Rate Plan. On November 1, 2022, OG&E filed against the request for rehearing. Despite the denial of the extension request, the Formula Rate Plan Rider will continue until new rates are set in a future general rate review. Arkansas 2022 Formula Rate Plan Filing On October 3, 2022, OG&E filed its fifth evaluation report under its Formula Rate Plan, including a request to increase its Arkansas retail revenues by $8.5 million. If approved, new rates will be effective April 1, 2023. OCC Proceedings Oklahoma Retail Electric Supplier Certified Territory Act Causes Several rural electric cooperative electricity suppliers have filed complaints with the OCC alleging that OG&E has violated the Oklahoma Retail Electric Supplier Certified Territory Act. OG&E believes it is lawfully serving customers specifically exempted from this act and has presented evidence and testimony to the OCC supporting its position. There have been five complaint cases initiated at the OCC, and the OCC has issued decisions on each of them. The OCC ruled in favor of the electric cooperatives in three of those cases and ruled in favor of OG&E in two of those cases. All five of those cases have been appealed to the Oklahoma Supreme Court, where they have been made companion cases but will be individually briefed and have individual final decisions. If the Oklahoma Supreme Court ultimately were to find that some or all of the customers being served are not exempted from the Oklahoma Retail Electric Supplier Certified Territory Act, OG&E would have to evaluate the recoverability of some plant investments made to serve these customers. The total amount of OG&E's plant investments made to serve the customers in all five cases is approximately $28.0 million, of which $11.7 million applies to the three cases where the OCC ruled in favor of the electric cooperatives. In addition to the evaluation of the recoverability of the investments, OG&E may also be required to reimburse certified territory suppliers for an amount of lost revenue. The amount of such lost revenue would depend on how the OCC calculates the revenue requirement but could range from approximately $17.4 million to $58.0 million for all five cases, of which $4.1 million to $7.0 million would apply to the three cases where the OCC ruled in favor of the electric cooperatives. 2021 Oklahoma Fuel Prudency On July 1, 2022, the Public Utility Division Staff filed their application initiating the review of the 2021 fuel adjustment clause and prudence review. OG&E filed its Minimum Filing Requirements and Supporting Testimony on August 30, 2022, and responsive testimony is due January 6, 2023. Fuel Cost Adjustment Show Cause On September 29, 2022, the OCC Public Utility Division Staff initiated a cause to determine the appropriate methodology to recover OG&E's fuel clause under recovery balance of $424.0 million and how OG&E's fuel factors should be set going forward. The Staff requested that OG&E explain how it arrived at the noted under recovery balance, explain its fuel forecasting process, justify its amortization period of 24 months and explain the adequacy of its resource mix and fuel supply plans. Updated fuel factors were implemented by OG&E on October 1, 2022 to recover the balance from customers over 24 months. The Staff did not oppose OG&E's implementation of updated fuel factors on an interim basis and subject to refund. A hearing on the merits is scheduled to begin on November 3, 2022. A final order on this matter is expected by November 11, 2022, which would comply with the statutory requirement that an order be issued seven days post-hearing. SPP Proceedings Planning Reserve Margin and Performance Based Accreditation On July 26, 2022, the SPP Board of Directors approved a planning reserve margin increase from 12 percent to 15 percent that each load serving entity, such as OG&E, must maintain. This change will be effective for the summer of 2023. At the same time, the SPP Board of Directors also approved a new unit accreditation methodology, which begins a phased implementation starting in the summer of 2024. As a result, OG&E is currently evaluating its plan to fill the incremental capacity needs brought about by these policy changes.

In October 2021, OG&E filed its fourth evaluation report under its Formula Rate Plan, and on February 1, 2022, OG&E, the APSC General Staff and the Office of the Arkansas Attorney General filed a non-unanimous joint settlement agreement, which included an annual electric revenue increase of $4.2 million. The only non-signatory to the settlement agreement agreed not to oppose the settlement. On March 4, 2022, the APSC issued a final order approving the non-unanimous settlement agreement, and new rates became effective April 1, 2022.

In December 2021, the OCC approved a settlement agreement in a final financing order authorizing the issuance of securitization bonds in an amount up to $760.0 million, which included estimated finance costs and was subject to change for carrying costs, any updates from the SPP settlement process and actual securitization issuance costs. On July 20, 2022, the ODFA issued the securitization bonds consistent with the OCC's order.

In connection with the securitization transaction, the ODFA and OG&E entered into an agreement on July 20, 2022 whereby the ODFA purchased, and OG&E sold, the securitization property that was created pursuant to legislation enacted by the State of Oklahoma in April 2021 and the financing order received from the OCC in December 2021. Such securitization property includes the right to assess, impose, adjust, collect and receive funds, in the form of the winter event securitization charge, from OG&E's existing and future Oklahoma customers in amounts intended to be sufficient to pay the principal and interest and financing charges on the securitization bonds. On July 20, 2022, OG&E received proceeds of approximately $750 million for the sale of the securitization property, which represented the amount of the securitization bonds sold less the issuance costs. OG&E used these proceeds to fund the Oklahoma Winter Storm Uri regulatory asset by recovering the authorized extreme, extraordinary fuel and purchased power costs incurred during Winter Storm Uri, as well as carrying costs. Beginning August 1, 2022, OG&E acts as a servicer for collecting the funds from Oklahoma customers that are then submitted to the ODFA to repay the securitization bonds over 28 years.

In December 2021, OG&E filed a general rate review in Oklahoma seeking a rate increase of $163.5 million and a 10.2 percent return on equity based on a common equity percentage of 53.37 percent. The rate review was based on a September 30, 2021 test year and included a request for recovery of $1.2 billion of capital investment since the last general rate review. OG&E had the right to implement interim rates subject to refund beginning July 1, 2022 (180 days after the filing of its application on December 30, 2021). On July 1, 2022, OG&E implemented an annual interim rate increase of $30.0 million, subject to refund for amounts in excess of the rates approved by the OCC.

On September 8, 2022, the OCC approved a Joint Stipulation and Settlement Agreement that had been entered into by OG&E, the OCC Public Utility Division Staff, the Oklahoma Attorney General, the OG&E Shareholders Association, Oklahoma Industrial Energy Consumers and other intervenors. Non-signatory parties had agreed not to contest this agreement. Key terms of the agreement, as approved by the OCC, include, among others:

•OG&E would issue a refund, over a 12-month period, for the tax expense savings arising from the reduction in the Oklahoma state corporate income tax rate from 6 percent to 4 percent for the period from January 1, 2022 through June 30, 2022, as well as amortize over five years the excess accumulated deferred income tax balance resulting from this corporate tax rate change;

•OG&E's Grid Enhancement Plan interim recovery would continue and updated terms include: (i) cost recovery through a rider mechanism will be limited to projects placed in service in 2022, 2023 and 2024, capped at a revenue requirement of $6.0 million for each annual investment plan and include communication, automation and technology systems projects, as well as certain weather hardening projects; and (ii) the rider mechanism will terminate by the issuance of a final order in OG&E's first general rate review following completion of projects included in the 2024 annual investment plan or no later than July 1, 2025;

•Regulatory accounting treatments approved include, among other things, the establishment of a regulatory asset to defer operation and maintenance costs associated with OG&E's SAP S/4 HANA enterprise resource planning system project for consideration in future rate proceedings with the carrying cost accruing at OG&E's short-term cost of debt, the amortization of COVID-19 regulatory asset balance over five years and the amortization of over/under-recovery balance of the pension tracker over 15 years, which is a change from the previous five-year recovery period.

Various proceedings pending before state or federal regulatory agencies are described below. Unless stated otherwise, the Registrants cannot predict when the regulatory agency will act or what action the regulatory agency will take. The Registrants' financial results are dependent in part on timely and constructive decisions by the regulatory agencies that set OG&E's rates.

Under the SPP Open Access Transmission Tariff, costs of participant-funded, or "sponsored," transmission upgrades may be recovered from other SPP customers whose transmission service depends on capacity enabled by the upgrade. The SPP Open Access Transmission Tariff required the SPP to charge for these upgrades beginning in 2008, but the SPP had not been charging its customers for these upgrades due to information system limitations. However, the SPP had informed participants in the market that these charges would be forthcoming. In July 2016, the FERC granted the SPP's request to recover the charges not billed since 2008. The SPP subsequently billed OG&E for these charges and credited OG&E related to transmission upgrades that OG&E had sponsored, which resulted in OG&E being a net receiver of sponsored upgrade credits. The majority of these net credits were refunded to customers through OG&E's various rate riders that include SPP activity with the remaining amounts retained by OG&E.

Several companies that were net payers of Z2 charges sought rehearing of the FERC's July 2016 order; however, in November 2017, the FERC denied the rehearing requests. In January 2018, one of the impacted companies appealed the FERC's decision to the U.S. Court of Appeals for the District of Columbia Circuit. In July 2018, that court granted a motion requested by the FERC that the case be remanded back to the FERC for further examination and proceedings. In February 2019, the FERC reversed its July 2016 order and November 2017 rehearing denial, ruled that the SPP violated its tariff to charge for the 2008 through 2015 period in 2016, held that the SPP tariff provision that prohibited those charges could not be waived and ordered the SPP to develop a plan to refund the payments but not to implement the refunds until further ordered to do so. In response, in April 2019, OG&E filed a request for rehearing with the FERC, and in May 2019, OG&E filed a FERC 206 complaint against the SPP, alleging that the SPP's forced unwinding of the revenue credit payments to OG&E would violate the provisions of the Sponsored Upgrade Agreement and of the applicable tariff. OG&E's filing requested that the FERC rule that the SPP is not entitled to seek refunds or in any other way seek to unwind the revenue credit payments it had paid to OG&E pursuant to the Sponsored Upgrade Agreement. The SPP's response to OG&E's filing agreed that OG&E should be entitled to keep its Z2 payments and argued that the SPP should not be held responsible for those payments if refunds are ordered. Further, the SPP has requested the FERC to negotiate a global settlement with all impacted parties, including other project sponsors who, like OG&E, have also filed complaints at FERC contending that the payments they have received cannot properly be unwound.

In February 2020, the FERC denied OG&E's request for rehearing of its February 2019 order, denying the waiver and ruling that the SPP must seek refunds from project sponsors for Z2 payments for the 2008 through 2015 period and pay them back to transmission owners. The FERC also denied the SPP's request for a stay and for institution of settlement procedures. The FERC stated it would not institute settlement procedures unless parties on both sides of the matter requested them. The FERC did not rule on OG&E's complaint or the complaints of other project sponsors, or consider the SPP's refund plan. The FERC thus has not set any date for payment of refunds. In March 2020, OG&E petitioned the U.S. Court of Appeals for the District of Columbia Circuit for review of the FERC's order denying the waiver and requiring refunds. The court issued a decision on August 27, 2021, denying review and holding that the SPP was prohibited by the filed rate doctrine from imposing Z2 charges during the 2008 through 2015 historical period. The court further held that the FERC reasonably exercised its remedial authority to order the SPP to refund the retroactive upgrade charge. The court did not direct a time frame or procedures for the SPP to implement refunds. OG&E and the SPP filed a petition for rehearing of the court's decision, which was denied in October 2021. The court returned the matter to the FERC for action in accordance with its opinion in November 2021.

If the FERC proceeds to order refunds in full, OG&E estimates it would be required to refund $13.0 million, which is net of amounts paid to other utilities for upgrades and would be subject to interest at the FERC-approved rate. The SPP has stated in filings it made with the FERC while the appeal was pending that there are considerable complexities in implementing the refunds that will have to be resolved before they can be paid. Payment of refunds would shift recovery of these upgrade credits to future periods. The SPP filed an update on January 4, 2022 confirming that administering refunds would be complex and could take years unless the SPP is allowed to make certain simplifying assumptions. It also urged that all pending complaint proceedings, including four complaints against the SPP, be resolved before the refund process is ordered to begin. OG&E and other parties filed responses to the SPP report, and the matter remains pending at the FERC. Of the $13.0 million, the Registrants would be impacted by $5.0 million in expense that initially benefited the Registrants in 2016, and OG&E customers would incur a net impact of $8.0 million in expense through rider mechanisms or the FERC formula rate. As of September 30, 2022, the Registrants have reserved $13.0 million plus estimated interest for a potential refund.

In January 2020, the FERC acted on an SPP proposal to eliminate Attachment Z2 revenue crediting and replace it with a different rate mechanism that would provide project sponsors, such as OG&E, the same level of recovery, and rejected the proposal to the extent it would limit recovery to the amount of the upgrade sponsor's directly assigned upgrade costs with interest. The SPP resubmitted a proposal in April 2020 without this limited recovery, and with the alternative rate mechanism, and the FERC approved it in June 2020, effective July 1, 2020. No party sought rehearing of the order, and it is now final. This order would only prospectively impact OG&E and its recovery of any future upgrade costs that it may incur as a project sponsor subsequent to July 2020. All of the existing projects that are eligible to receive revenue credits under Attachment Z2, which includes the $13.0 million at issue in OG&E's appeal as discussed above, will continue to do so.

The FERC issued a NOPR in March 2020, and issued a supplemental NOPR in April 2021, proposing to update its transmission incentives policy. Among other things, the NOPR proposes (i) the current 50-basis point return on equity adder for RTO/ISO participation would be applicable only to transmitting utilities that join an RTO/ISO, and this incentive would only apply for the first three years in which the utility is an RTO/ISO member and (ii) transmitting utilities that have been members of an RTO/ISO for three years or more, such as OG&E, would be required to make a compliance filing to remove the existing return on equity adder from their rates. Currently, there is no specific deadline for the FERC to take further action, and it is unknown whether the FERC will address the RTO participation adder individually or as part of a larger order on transmission incentives.

In February 2021, Winter Storm Uri resulted in record winter peak demand for electricity and extremely high natural gas and purchased power prices in OG&E's service territory. On April 1, 2021, OG&E filed with the APSC a Motion for Authority to Establish Special Regulatory Treatment within the Energy Cost Recovery Rider to Defer Extraordinary Fuel Costs Incurred Due to Winter Storm Uri. More specifically, OG&E's motion sought approval to defer, amortize and recover the extraordinary fuel costs over a ten-year period with a carrying charge of OG&E's pre-tax rate of return of 6.60 percent, through a special factor within OG&E's Energy Cost Recovery Rider beginning with the first billing cycle of May 2021. On April 13, 2021, the APSC issued an order allowing OG&E interim recovery at an interest rate equal to the customer deposit interest rate, which is currently 0.8 percent, over a period of ten years beginning with the first billing cycle of May 2021. Recovery is subject

In April 2021, Arkansas enacted legislation to amend its storm recovery securitization statute to allow for both electric and gas utilities to recover through securitization extraordinary natural gas, fuel and purchased power costs caused by storms. In May 2021, the APSC approved OG&E's motion for suspension of procedural schedule to investigate and evaluate the potential securitization recovery of the Arkansas jurisdictional portion of the Winter Storm Uri costs.

On July 5, 2022, OG&E filed a motion to request recovery of the regulatory asset balance over 10 years using a weighted average cost of capital instead of through securitization. On July 15, 2022, the APSC Staff filed a response to OG&E’s motion stating the Staff does not oppose OG&E's request for recovery using a weighted average cost of capital, as long as no other party to the case opposes. Subsequently, other intervenors have filed their opposition to OG&E using a weighted average cost of capital for recovery. On August 1, 2022, the APSC issued a procedural order to set a schedule for additional testimony, and a hearing on the merits is expected to be held on December 2, 2022. As of September 30, 2022, OG&E has deferred $80.6 million to a regulatory asset, as indicated in Note 1.

On May 18, 2022, the APSC issued an order granting OG&E's request for a five-year extension of the Formula Rate Plan Rider with certain terms and conditions, including continuation of OG&E's current return on equity of 9.5 percent and a change to OG&E's current debt-to-equity ratio of 50/50 percent to 55/45 percent. On June 17, 2022, OG&E filed a request for rehearing seeking reconsideration by the APSC of their decision to alter the Formula Rate Plan Rider's capital structure. On September 19, 2022, the APSC issued an order reversing its May 18, 2022 order and denying the extension of OG&E's Formula Rate Plan Rider. On September 20, 2022, the APSC Staff filed a motion for clarification for the extension denial, and OG&E, the Arkansas Attorney General and Arkansas River Valley Energy Consumers filed responses to the clarification. On September 30, 2022, the APSC issued an order clarifying that OG&E is authorized to file its 2022 and 2023 evaluation reports under the Formula Rate Plan Rider to true-up prior projected year rate adjustments. On October 28, 2022, Arkansas River Valley Energy Consumers and Walmart Inc. filed a request for rehearing of the APSC's September 30, 2022 order and asked the APSC to reverse its position and prohibit OG&E from making any further filings under its current Formula Rate Plan. On November 1, 2022, OG&E filed against the request for rehearing. Despite the denial of the extension request, the Formula Rate Plan Rider will continue until new rates are set in a future general rate review.

Several rural electric cooperative electricity suppliers have filed complaints with the OCC alleging that OG&E has violated the Oklahoma Retail Electric Supplier Certified Territory Act. OG&E believes it is lawfully serving customers specifically exempted from this act and has presented evidence and testimony to the OCC supporting its position. There have been five complaint cases initiated at the OCC, and the OCC has issued decisions on each of them. The OCC ruled in favor of the electric cooperatives in three of those cases and ruled in favor of OG&E in two of those cases. All five of those cases have been appealed to the Oklahoma Supreme Court, where they have been made companion cases but will be individually briefed and have individual final decisions.

If the Oklahoma Supreme Court ultimately were to find that some or all of the customers being served are not exempted from the Oklahoma Retail Electric Supplier Certified Territory Act, OG&E would have to evaluate the recoverability of some plant investments made to serve these customers. The total amount of OG&E's plant investments made to serve the customers in all five cases is approximately $28.0 million, of which $11.7 million applies to the three cases where the OCC ruled in favor of the electric cooperatives. In addition to the evaluation of the recoverability of the investments, OG&E may also be required to reimburse certified territory suppliers for an amount of lost revenue. The amount of such lost revenue would depend on how the OCC calculates the revenue requirement but could range from approximately $17.4 million to $58.0 million for all five cases, of which $4.1 million to $7.0 million would apply to the three cases where the OCC ruled in favor of the electric cooperatives.

On September 29, 2022, the OCC Public Utility Division Staff initiated a cause to determine the appropriate methodology to recover OG&E's fuel clause under recovery balance of $424.0 million and how OG&E's fuel factors should be set going forward. The Staff requested that OG&E explain how it arrived at the noted under recovery balance, explain its fuel forecasting process, justify its amortization period of 24 months and explain the adequacy of its resource mix and fuel supply plans. Updated fuel factors were implemented by OG&E on October 1, 2022 to recover the balance from customers over 24 months. The Staff did not oppose OG&E's implementation of updated fuel factors on an interim basis and subject to refund. A hearing on the merits is scheduled to begin on November 3, 2022. A final order on this matter is expected by November 11, 2022, which would comply with the statutory requirement that an order be issued seven days post-hearing.

On July 26, 2022, the SPP Board of Directors approved a planning reserve margin increase from 12 percent to 15 percent that each load serving entity, such as OG&E, must maintain. This change will be effective for the summer of 2023. At the same time, the SPP Board of Directors also approved a new unit accreditation methodology, which begins a phased implementation starting in the summer of 2024. As a result, OG&E is currently evaluating its plan to fill the incremental capacity needs brought about by these policy changes.