Rate Matters and Regulation	12 Months Ended
Dec. 31, 2022
Regulated Operations [Abstract]
Rate Matters and Regulation	14. Rate Matters and Regulation Regulation and Rates OG&E's retail electric tariffs are regulated by the OCC in Oklahoma and by the APSC in Arkansas. The issuance of certain securities by OG&E is also regulated by the OCC and the APSC. OG&E's transmission activities, short-term borrowing authorization and accounting practices are subject to the jurisdiction of the FERC. The Secretary of the U.S. Department of Energy has jurisdiction over some of OG&E's facilities and operations. In 2022, 88 percent of OG&E's electric revenue was subject to the jurisdiction of the OCC, eight percent to the APSC and four percent to the FERC. The OCC and the APSC require that, among other things, (i) OGE Energy permits the OCC and the APSC access to the books and records of OGE Energy and its affiliates relating to transactions with OG&E; (ii) OGE Energy employ accounting and other procedures and controls to protect against subsidization of non-utility activities by OG&E's customers; and (iii) OGE Energy refrain from pledging OG&E assets or income for affiliate transactions. In addition, the FERC has access to the books and records of OGE Energy and its affiliates as the FERC deems relevant to costs incurred by OG&E or necessary or appropriate for the protection of utility customers with respect to the FERC jurisdictional rates. 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. 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 seeking approval to defer, amortize and recover the extraordinary fuel costs over a 10-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 over a period of 10 years beginning with the first billing cycle of May 2021, subject to true-up. 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. A hearing on the merits was scheduled to be held on December 2, 2022 but was cancelled after all interested parties agreed to waive the hearing and have the APSC decide the matter based on the established record. In January 2023, the APSC issued an order approving OG&E's requested relief and authorizing OG&E to amortize the regulatory asset balance over 10 years using a pre-tax weighted average cost of capital of 6.49 percent as a carrying charge beginning March 2021. The impact of this order will be recorded beginning in the first quarter of 2023, as the order was received from the APSC in January 2023. 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 submitted its opposition to the request for rehearing. On November 28, 2022, the APSC granted the application for rehearing solely for the purpose of further consideration. On January 20, 2023, the APSC issued an order denying the request for rehearing of the September 30, 2022 order and ruling that OG&E is able to undertake two more true-up updates to its Formula Rate Plan Rider with adjustments to rates occurring in April 2023 and April 2024. Despite the denial of OG&E's extension request, the Formula Rate Plan Rider will continue until new rates are set in a future general rate review. 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 Attachment Z2 of 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 Tariff required the SPP to charge for these upgrades beginning in 2008, but the SPP did not begin charging its customers for these upgrades until 2016 due to information system limitations. At that time, the SPP sought a waiver of a time limitation in its tariff that otherwise would have prevented it from waiting until 2016 to bill for the 2008 through 2015 period. The FERC granted the waiver, and the SPP then billed OG&E as a user for these Z2 charges while simultaneously crediting OG&E as a sponsor of Z2 transmission upgrades, resulting in OG&E being a net recipient 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 2016 order approving the waiver and then appealed it. While that appeal was pending, the FERC obtained a remand and then reversed itself and ruled that the SPP tariff provision that prohibited the 2008 through 2015 charges could not be waived. It 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 at the FERC. The next month, it also filed a Complaint at the FERC against the SPP contending that the SPP and not OG&E should bear the cost of any refunds resulting from the SPP's tariff violation and that SPP’s actions also violated its contracts with OG&E. In February 2020, the FERC denied OG&E's request for rehearing but did not consider SPP's refund plan. No date for payment of refunds was established. In August 2021, the U.S. Court of Appeals for the District of Columbia Circuit denied OG&E's petition for review of the FERC's order denying the waiver and requiring refunds. After denying rehearing of its ruling, the court of appeals returned the matter in November 2021 to the FERC for further proceedings in accordance with its opinion. The FERC has not acted on that remand. 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 with the FERC both before and after the court of appeals decision 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 a report 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. The SPP also urged that all pending complaint proceedings, including OG&E's complaint and three similar complaints against the SPP, be resolved before any 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 December 31, 2022, the Registrants have reserved $13.0 million plus estimated interest for a potential refund. In November 2022, the FERC issued an order denying OG&E's complaint against SPP. It also issued orders granting the other three complaints against the SPP in part but awarded no relief. All four complainants timely sought rehearing of these orders. Those rehearing petitions remain pending, though OG&E and the other complainants can appeal them now if they choose to do so on the basis that they have been deemed denied by operation of law. The FERC, however, can continue to consider the rehearings on the merits, and the complainants will be able appeal any denial on the merits as well. In June 2020, the FERC approved, effective July 1, 2020, 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. This elimination of the Attachment Z2 revenue crediting 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 will remain eligible, which includes the $13.0 million that is at issue in the remand from OG&E's appeal and in OG&E's complaint proceeding. 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 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, which reflects a cap of 4.0 percent of annualized filing year revenues as of June 2022. After utilizing an adjustment to annualized filing year revenues as of October 2022, the capped revenue requirement increase rose to approximately $9.6 million. On December 29, 2022, intervening parties filed errors and objections to OG&E's fifth evaluation report. The Arkansas Attorney General made no recommended adjustments to the revenue requirement, and the Arkansas Valley Electric Consumers reiterated legal arguments about the legal permissibility of the fifth evaluation report. The APSC Staff made certain minor adjustments but agreed that the overall revenue requirement adjustment should reflect the capped amount of $9.6 million. On February 1, 2023, OG&E and the APSC Staff filed a non-unanimous joint settlement agreement, which includes an annual electric revenue increase of $9.6 million. The Arkansas Attorney General and the Arkansas Valley Electric Consumers have agreed not to oppose the settlement, and the settlement agreement is subject to approval by the APSC. OG&E and the APSC Staff have requested a final order from the APSC by early March 2023, with new rates to be effective April 1, 2023. Prudence Review - Winter Storm Uri Extraordinary Costs On February 2, 2023, the APSC issued an order to initiate proceedings to address the prudence and appropriate allocation of the extraordinary costs incurred by Arkansas jurisdictional electric and natural gas utilities during Winter Storm Uri. As discussed above, in January 2023, the APSC issued an order approving OG&E's recovery of the Winter Storm Uri regulatory asset balance, which included setting the carrying charges and term of recovery. The APSC did not rule on prudence or cost allocation at that time. OG&E's direct testimony is due in April 2024, and a hearing on the merits is expected to begin in August 2024. 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 $16.2 million to $63.9 million for all five cases, of which $4.4 million to $7.9 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 OCC Public Utility Division Staff filed their application initiating the review of the 2021 fuel adjustment clause and prudence review. On February 21, 2023, a Joint Stipulation and Settlement Agreement was filed, and OG&E filed its testimony in support of such agreement. The stipulating parties, which include the OCC Public Utility Division Staff and the Oklahoma Attorney General, agree that: (i) OG&E's practices, policies and judgment for fuel procurement during 2021 were prudent; (ii) OG&E's power purchase costs and expenses, monthly fuel filings and processes and fuel-related investments and decisions for 2021 were fair, just and reasonable and (iii) OG&E exercised prudent judgement pertaining to all such matters and that the electric generation, purchased power and fuel procurement expenses were prudently incurred. Further, the stipulating parties agree to certain revisions of the fuel clause adjustment tariff, including a revised semi-annual fuel clause adjustment factor redetermination process which will be subject to the OCC Public Utility Division approval or denial. A hearing on the merits for the Joint Stipulation and Settlement Agreement is scheduled for February 23, 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 OCC Public Utility Division 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 was held on November 3 and 4, 2022. Despite several public deliberations, the OCC has not issued a final order in this proceeding. On January 1, 2023, OG&E implemented its annual redetermination of its fuel factors, without further action or opposition from the OCC. 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 for conventional generation, effective 2024. As a result, OG&E is currently evaluating its plan to fill the incremental capacity needs brought about by these policy changes.

OG&E's retail electric tariffs are regulated by the OCC in Oklahoma and by the APSC in Arkansas. The issuance of certain securities by OG&E is also regulated by the OCC and the APSC. OG&E's transmission activities, short-term borrowing authorization and accounting practices are subject to the jurisdiction of the FERC. The Secretary of the U.S. Department of Energy has jurisdiction over some of OG&E's facilities and operations. In 2022, 88 percent of OG&E's electric revenue was subject to the jurisdiction of the OCC, eight percent to the APSC and four percent to the FERC.

The OCC and the APSC require that, among other things, (i) OGE Energy permits the OCC and the APSC access to the books and records of OGE Energy and its affiliates relating to transactions with OG&E; (ii) OGE Energy employ accounting and other procedures and controls to protect against subsidization of non-utility activities by OG&E's customers; and (iii) OGE Energy refrain from pledging OG&E assets or income for affiliate transactions. In addition, the FERC has access to the books and records of OGE Energy and its affiliates as the FERC deems relevant to costs incurred by OG&E or necessary or appropriate for the protection of utility customers with respect to the FERC jurisdictional rates.

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 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 seeking approval to defer, amortize and recover the extraordinary fuel costs over a 10-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 over a period of 10 years beginning with the first billing cycle of May 2021, subject to true-up.

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. A hearing on the merits was scheduled to be held on December 2, 2022 but was cancelled after all interested parties agreed to waive the hearing and have the APSC decide the matter based on the established record. In January 2023, the APSC issued an order approving OG&E's requested relief and authorizing OG&E to amortize the regulatory asset balance over 10 years using a pre-tax weighted average cost of capital of 6.49 percent as a carrying charge beginning March 2021. The impact of this order will be recorded beginning in the first quarter of 2023, as the order was received from the APSC in January 2023.

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 submitted its opposition to the request for rehearing. On November 28, 2022, the APSC granted the application for rehearing solely for the purpose of further consideration. On January 20, 2023, the APSC issued an order denying the request for rehearing of the September 30, 2022 order and ruling that OG&E is able to undertake two more true-up updates to its Formula Rate Plan Rider with adjustments to rates occurring in April 2023 and April 2024. Despite the denial of OG&E's extension request, the Formula Rate Plan Rider will continue until new rates are set in a future general rate review.

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:

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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;

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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;

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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;

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OG&E's Grid Enhancement Plan projects recorded as of March 31, 2022 would be considered prudent and be included in base rates;

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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;

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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.

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 Attachment Z2 of 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 Tariff required the SPP to charge for these upgrades beginning in 2008, but the SPP did not begin charging its customers for these upgrades until 2016 due to information system limitations. At that time, the SPP sought a waiver of a time limitation in its tariff that otherwise would have prevented it from waiting until 2016 to bill for the 2008 through 2015 period. The FERC granted the waiver, and the SPP then billed OG&E as a user for these Z2 charges while simultaneously crediting OG&E as a sponsor of Z2 transmission upgrades, resulting in OG&E being a net recipient 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 2016 order approving the waiver and then appealed it. While that appeal was pending, the FERC obtained a remand and then reversed itself and ruled that the SPP tariff provision that prohibited the 2008 through 2015 charges could not be waived. It 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 at the FERC. The next month, it also filed a Complaint at the FERC against the SPP contending that the SPP and not OG&E should bear the cost of any refunds resulting from the SPP's tariff violation and that SPP’s actions also violated its contracts with OG&E. In February 2020, the FERC denied OG&E's request for rehearing but did not consider SPP's refund plan. No date for payment of refunds was established. In August 2021, the U.S. Court of Appeals for the District of Columbia Circuit denied OG&E's petition for review of the FERC's order denying the waiver and requiring refunds. After denying rehearing of its ruling, the court of appeals returned the matter in November 2021 to the FERC for further proceedings in accordance with its opinion. The FERC has not acted on that remand.

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 with the FERC both before and after the court of appeals decision 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 a report 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. The SPP also urged that all pending complaint proceedings, including OG&E's complaint and three similar complaints against the SPP, be resolved before any 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 December 31, 2022, the Registrants have reserved $13.0 million plus estimated interest for a potential refund.

In November 2022, the FERC issued an order denying OG&E's complaint against SPP. It also issued orders granting the other three complaints against the SPP in part but awarded no relief. All four complainants timely sought rehearing of these orders. Those rehearing petitions remain pending, though OG&E and the other complainants can appeal them now if they choose to do so on the basis that they have been deemed denied by operation of law. The FERC, however, can continue to consider the rehearings on the merits, and the complainants will be able appeal any denial on the merits as well.

In June 2020, the FERC approved, effective July 1, 2020, 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. This elimination of the Attachment Z2 revenue crediting 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 will remain eligible, which includes the $13.0 million that is at issue in the remand from OG&E's appeal and in OG&E's complaint proceeding.

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.

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, which reflects a cap of 4.0 percent of annualized filing year revenues as of June 2022. After utilizing an adjustment to annualized filing year revenues as of October 2022, the capped revenue requirement increase rose to approximately $9.6 million. On December 29, 2022, intervening parties filed errors and objections to OG&E's fifth evaluation report. The Arkansas Attorney General made no recommended adjustments to the revenue requirement, and the Arkansas Valley Electric Consumers reiterated legal arguments about the legal permissibility of the fifth evaluation report. The APSC Staff made certain minor adjustments but agreed that the overall revenue requirement adjustment should reflect the capped amount of $9.6 million. On February 1, 2023, OG&E and the APSC Staff filed a non-unanimous joint settlement agreement, which includes an annual electric revenue increase of $9.6 million. The Arkansas Attorney General and the Arkansas Valley Electric Consumers have agreed not to oppose the settlement, and the settlement agreement is subject to approval by the APSC. OG&E and the APSC Staff have requested a final order from the APSC by early March 2023, with new rates to be effective April 1, 2023.

On February 2, 2023, the APSC issued an order to initiate proceedings to address the prudence and appropriate allocation of the extraordinary costs incurred by Arkansas jurisdictional electric and natural gas utilities during Winter Storm Uri. As discussed above, in January 2023, the APSC issued an order approving OG&E's recovery of the Winter Storm Uri regulatory asset balance, which included setting the carrying charges and term of recovery. The APSC did not rule on prudence or cost allocation at that time. OG&E's direct testimony is due in April 2024, and a hearing on the merits is expected to begin in August 2024.

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 $16.2 million to $63.9 million for all five cases, of which $4.4 million to $7.9 million would apply to the three cases where the OCC ruled in favor of the electric cooperatives.

On July 1, 2022, the OCC Public Utility Division Staff filed their application initiating the review of the 2021 fuel adjustment clause and prudence review. On February 21, 2023, a Joint Stipulation and Settlement Agreement was filed, and OG&E filed its testimony in support of such agreement. The stipulating parties, which include the OCC Public Utility Division Staff and the Oklahoma Attorney General, agree that: (i) OG&E's practices, policies and judgment for fuel procurement during 2021 were prudent; (ii) OG&E's power purchase costs and expenses, monthly fuel filings and processes and fuel-related investments and decisions for 2021 were fair, just and reasonable and (iii) OG&E exercised prudent judgement pertaining to all such matters and that the electric generation, purchased power and fuel procurement expenses were prudently incurred. Further, the stipulating parties agree to certain revisions of the fuel clause adjustment tariff, including a revised semi-annual fuel clause adjustment factor redetermination process which will be subject to the OCC Public Utility Division approval or denial. A hearing on the merits for the Joint Stipulation and Settlement Agreement is scheduled for February 23, 2023.

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 OCC Public Utility Division 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 was held on November 3 and 4, 2022. Despite several public deliberations, the OCC has not issued a final order in this proceeding. On January 1, 2023, OG&E implemented its annual redetermination of its fuel factors, without further action or opposition from the OCC.

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 for conventional generation, effective 2024. As a result, OG&E is currently evaluating its plan to fill the incremental capacity needs brought about by these policy changes.