Rate Matters and Regulation	12 Months Ended
Dec. 31, 2023
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 2023, 86 percent of OG&E's electric revenue was subject to the jurisdiction of the OCC, eight percent to the APSC and six 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 2022 Formula Rate Plan Filing In October 2022, OG&E filed its fifth evaluation report under its Formula Rate Plan, and on February 1, 2023, OG&E and the APSC Staff filed a non-unanimous joint settlement agreement, which included an annual electric revenue increase of $9.6 million. The Arkansas Attorney General and the Arkansas Valley Electric Consumers agreed not to oppose the settlement. On March 2, 2023, the APSC issued a final order approving the non-unanimous settlement agreement, and new rates became effective April 1, 2023. Horseshoe Lake Modernization Plan On July 12, 2023, OG&E filed an application at the APSC seeking authorization to commence construction of two combustion turbines totaling 448 megawatts at its existing Horseshoe Lake generating facility. The Horseshoe Lake project is expected to cost approximately $331 million, excluding financing costs and property taxes, and the new generating units are expected to be placed into service in late 2026. Arkansas law requires a public utility to seek approval from the APSC to commence construction of a power-generating facility located outside the boundaries of the state of Arkansas. The APSC Staff filed direct testimony on September 15, 2023 recommending that the APSC grant OG&E approval to construct the combustion turbines, subject to a prudence review in a future proceeding. On October 16, 2023, the APSC issued an order which states that OG&E has complied with applicable Arkansas law and may commence construction of the Horseshoe Lake generating facility. OCC Proceedings 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 the OCC approved the Settlement Agreement on April 20, 2023. The Settlement Agreement provides 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 judgment pertaining to all such matters and that the electric generation, purchased power and fuel procurement expenses were prudently incurred. Further, the stipulating parties agreed 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. Pursuant to the Settlement Agreement, OG&E submitted new fuel factors to the OCC on October 10, 2023 and met with stakeholders on October 12, 2023. This adjustment was estimated to result in an average monthly residential bill decrease of approximately $21 beginning November 1, 2023. Horseshoe Lake Modernization Plan On May 31, 2023, OG&E filed an application at the OCC seeking approval for the cost associated with the purchase and installation of two combustion turbines totaling 448 megawatts at its existing Horseshoe Lake generating facility. The Horseshoe Lake project is expected to cost approximately $331 million, excluding financing costs and property taxes, and the new generating units are expected to be placed into service in late 2026. On November 21, 2023, the OCC approved a non-unanimous, non-contested Joint Stipulation and Settlement Agreement that was entered into by OG&E and certain intervenors, which allows for recovery of the jurisdictional portion of expenses up to $275 million, plus financing costs and property taxes, related to this project through a recovery mechanism when the new generating units are placed into service. In accordance with the settlement agreement, OG&E is required to file a general rate review to include the new generating units in base rates no later than one year after the implementation of the recovery mechanism. SPP Proceedings Planning Reserve Margin 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 was effective for the summer of 2023. OG&E secured short-term bilateral contracts for the capacity needed to satisfy the 2023 requirements brought about by the increase to the SPP’s planning reserve margin. 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. APSC Proceedings 2023 Formula Rate Plan Filing On October 2, 2023, OG&E filed its final evaluation report under its Formula Rate Plan, including a request to increase its Arkansas retail revenues by $4.7 million. On December 28, 2023, the APSC Staff filed testimony recommending an annual electric revenue increase of $3.5 million. No other party filed testimony responsive to OG&E's proposed rate adjustment. On January 30, 2024, OG&E and the APSC Staff filed an uncontested joint settlement agreement, which included an annual electric revenue increase of $3.5 million. The APSC is expected to issue a final order in this matter in March 2024, with new rates to be effective April 1, 2024. Capacity Power Purchase Agreement Cost Recovery On October 4, 2023, OG&E filed an application at the APSC seeking approval of a methodology for recovery of capacity costs associated with short-term power purchase agreements entered into to meet capacity needs in each of the years between 2023 and 2027. On December 29, 2023, the Administrative Law Judge issued an order authorizing OG&E to defer to a regulatory asset its capacity costs associated with short-term power purchase agreements for 2023, along with a carrying charge at the commission-approved customer deposit interest rate. The order requires OG&E and the parties to the case to develop a procedural schedule to address treatment for any expenses beyond the calendar year 2023. 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, 2023, the Registrants' reserve remains at $13.0 million plus estimated interest for a potential refund. In November 2022, the FERC issued an order denying OG&E's complaint against the 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. On June 27, 2023, the FERC made final its orders granting in part complaints filed against the SPP by OG&E and three other project sponsors (or groups thereof) on claims arising from the SPP’s failure to implement Attachment Z2 so that project sponsors could be paid as required under the tariff, but awarding no relief. OG&E and the other complainants have appealed to the U.S. Court of Appeals for the Eighth Circuit, where the matter has been briefed and is awaiting the scheduling of oral argument. It will likely be decided by the summer of 2024. 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. OCC Proceedings Oklahoma Retail Electric Supplier Certified Territory Act Causes As previously disclosed, several rural electric cooperative electricity suppliers filed complaints with the OCC alleging that OG&E, because it was providing service to large loads in another supplier's territory, had violated the Oklahoma Retail Electric Supplier Certified Territory Act. OG&E believes it is lawfully serving customers under specific exemptions under this act that allow it to serve customers having a load of one megawatt or greater. There were five complaint cases initiated at the OCC, and the OCC issued decisions on each of them. The OCC ruled in favor of the electric cooperatives in three of those cases under statutory interpretation and ruled in favor of OG&E in two of those cases under injunctive theory. All five of those cases were appealed to the Oklahoma Supreme Court. On April 4, 2023, the Oklahoma Supreme Court issued its opinion which vacated the OCC's injunctions with respect to four of the cases and held that the Oklahoma Retail Electric Supplier Certified Territory Act does not limit the mechanism by which OG&E may provide service to large loads in another supplier's territory pursuant to the one megawatt exception. The one pending legal issue left for the Oklahoma Supreme Court to resolve is a statutory interpretation on how a supplier calculates "connected load for initial full operation" for purposes of the exemption under the act. If the Oklahoma Supreme Court ultimately were to find that the customers being served in this single case 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 and may also be required to reimburse the certified territory supplier in this case for an amount of lost revenue. Such amounts would not be expected to be material to the Registrants' results of operations. 2022 Oklahoma Fuel Prudency On June 29, 2023, the Public Utility Division Staff filed their application initiating the review of the 2022 fuel adjustment clause and prudence review. OG&E filed its minimum filing requirements and supporting testimony on August 29, 2023. The OCC Staff filed testimony on January 19, 2024 recommending that the OCC find OG&E's 2022 fuel costs prudent. 2023 Oklahoma General Rate Review On December 29, 2023, OG&E filed a general rate review in Oklahoma seeking a rate increase of $332.5 million and a 10.5 percent return on equity based on a common equity percentage of 53.50 percent. The rate review seeks recovery of $1.3 billion of net capital investment since the last general rate review. A hearing on the merits is scheduled for June 17, 2024. SPP Proceedings Resource Capacity Accreditation In July 2022, the SPP Board of Directors approved a new unit accreditation methodology for conventional generation which requires submittal to and approval from the FERC prior to becoming effective. On March 2, 2023, the FERC rejected the SPP’s proposed capacity accreditation methodology for wind and solar generators. Following the FERC’s rejection, the SPP began an extensive review of both the methodology proposed for thermal resources which had not yet been submitted to the FERC, and the accreditation methodology for wind and solar generators. These methodologies were reviewed and approved by both the Regional State Committee and the SPP Board of Directors in late October 2023 and will be submitted to the FERC for approval. If approved by the FERC, both methodologies are expected to be effective in 2026 and may contribute to OG&E’s incremental capacity needs.

Rate Matters and Regulation

12 Months Ended

Dec. 31, 2023

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 2023, 86 percent of OG&E's electric revenue was subject to the jurisdiction of the OCC, eight percent to the APSC and six 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 2022 Formula Rate Plan Filing

In October 2022, OG&E filed its fifth evaluation report under its Formula Rate Plan, and on February 1, 2023, OG&E and the APSC Staff filed a non-unanimous joint settlement agreement, which included an annual electric revenue increase of $9.6 million. The Arkansas Attorney General and the Arkansas Valley Electric Consumers agreed not to oppose the settlement. On March 2, 2023, the APSC issued a final order approving the non-unanimous settlement agreement, and new rates became effective April 1, 2023.

Horseshoe Lake Modernization Plan

On July 12, 2023, OG&E filed an application at the APSC seeking authorization to commence construction of two combustion turbines totaling 448 megawatts at its existing Horseshoe Lake generating facility. The Horseshoe Lake project is expected to cost approximately $331 million, excluding financing costs and property taxes, and the new generating units are expected to be placed into service in late 2026. Arkansas law requires a public utility to seek approval from the APSC to commence construction of a power-generating facility located outside the boundaries of the state of Arkansas. The APSC Staff filed direct testimony on September 15, 2023 recommending that the APSC grant OG&E approval to construct the combustion turbines, subject to a prudence review in a future proceeding. On October 16, 2023, the APSC issued an order which states that OG&E has complied with applicable Arkansas law and may commence construction of the Horseshoe Lake generating facility.

OCC Proceedings

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 the OCC approved the Settlement Agreement on April 20, 2023. The Settlement Agreement provides 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 judgment pertaining to all such matters and that the electric generation, purchased power and fuel procurement expenses were prudently incurred. Further, the stipulating parties agreed 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. Pursuant to the Settlement Agreement, OG&E submitted new fuel factors to the OCC on October 10, 2023 and met with stakeholders on October 12, 2023. This adjustment was estimated to result in an average monthly residential bill decrease of approximately $21 beginning November 1, 2023.

Horseshoe Lake Modernization Plan

On May 31, 2023, OG&E filed an application at the OCC seeking approval for the cost associated with the purchase and installation of two combustion turbines totaling 448 megawatts at its existing Horseshoe Lake generating facility. The Horseshoe Lake project is expected to cost approximately $331 million, excluding financing costs and property taxes, and the new generating units are expected to be placed into service in late 2026. On November 21, 2023, the OCC approved a non-unanimous, non-contested Joint Stipulation and Settlement Agreement that was entered into by OG&E and certain intervenors, which allows for recovery of the jurisdictional portion of expenses up to $275 million, plus financing costs and property taxes, related to this project through a recovery mechanism when the new generating units are placed into service. In accordance with the settlement agreement, OG&E is required to file a

general rate review to include the new generating units in base rates no later than one year after the implementation of the recovery mechanism.

SPP Proceedings

Planning Reserve Margin

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 was effective for the summer of 2023. OG&E secured short-term bilateral contracts for the capacity needed to satisfy the 2023 requirements brought about by the increase to the SPP’s planning reserve margin.

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.

APSC Proceedings

2023 Formula Rate Plan Filing

On October 2, 2023, OG&E filed its final evaluation report under its Formula Rate Plan, including a request to increase its Arkansas retail revenues by $4.7 million. On December 28, 2023, the APSC Staff filed testimony recommending an annual electric revenue increase of $3.5 million. No other party filed testimony responsive to OG&E's proposed rate adjustment. On January 30, 2024, OG&E and the APSC Staff filed an uncontested joint settlement agreement, which included an annual electric revenue increase of $3.5 million. The APSC is expected to issue a final order in this matter in March 2024, with new rates to be effective April 1, 2024.

Capacity Power Purchase Agreement Cost Recovery

On October 4, 2023, OG&E filed an application at the APSC seeking approval of a methodology for recovery of capacity costs associated with short-term power purchase agreements entered into to meet capacity needs in each of the years between 2023 and 2027. On December 29, 2023, the Administrative Law Judge issued an order authorizing OG&E to defer to a regulatory asset its capacity costs associated with short-term power purchase agreements for 2023, along with a carrying charge at the commission-approved customer deposit interest rate. The order requires OG&E and the parties to the case to develop a procedural schedule to address treatment for any expenses beyond the calendar year 2023.

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, 2023, the Registrants' reserve remains at $13.0 million plus estimated interest for a potential refund.

In November 2022, the FERC issued an order denying OG&E's complaint against the 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. On June 27, 2023, the FERC made final its orders granting in part complaints filed against the SPP by OG&E and three other project sponsors (or groups thereof) on claims arising from the SPP’s failure to implement Attachment Z2 so that project sponsors could be paid as required under the tariff, but awarding no relief. OG&E and the other complainants have appealed to the U.S. Court of Appeals for the Eighth Circuit, where the matter has been briefed and is awaiting the scheduling of oral argument. It will likely be decided by the summer of 2024.

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.

OCC Proceedings

Oklahoma Retail Electric Supplier Certified Territory Act Causes

As previously disclosed, several rural electric cooperative electricity suppliers filed complaints with the OCC alleging that OG&E, because it was providing service to large loads in another supplier's territory, had violated the Oklahoma Retail Electric Supplier Certified Territory Act. OG&E believes it is lawfully serving customers under specific exemptions under this act that allow it to serve customers having a load of one megawatt or greater. There were five complaint cases initiated at the OCC, and the OCC issued decisions on each of them. The OCC ruled in favor of the electric cooperatives in three of those cases under statutory interpretation and ruled in favor of OG&E in two of those cases under injunctive theory. All five of those cases were appealed to the Oklahoma Supreme Court.

On April 4, 2023, the Oklahoma Supreme Court issued its opinion which vacated the OCC's injunctions with respect to four of the cases and held that the Oklahoma Retail Electric Supplier Certified Territory Act does not limit the mechanism by which OG&E may provide service to large loads in another supplier's territory pursuant to the one megawatt exception. The one pending legal issue left for the Oklahoma Supreme Court to resolve is a statutory interpretation on how a supplier calculates "connected load for initial full operation" for purposes of the exemption under the act. If the Oklahoma Supreme Court ultimately were to find that the customers being served in this single case 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 and may also be required to reimburse the certified territory supplier in this case for an amount of lost revenue. Such amounts would not be expected to be material to the Registrants' results of operations.

2022 Oklahoma Fuel Prudency

On June 29, 2023, the Public Utility Division Staff filed their application initiating the review of the 2022 fuel adjustment clause and prudence review. OG&E filed its minimum filing requirements and supporting testimony on August 29, 2023. The OCC Staff filed testimony on January 19, 2024 recommending that the OCC find OG&E's 2022 fuel costs prudent.

2023 Oklahoma General Rate Review

On December 29, 2023, OG&E filed a general rate review in Oklahoma seeking a rate increase of $332.5 million and a 10.5 percent return on equity based on a common equity percentage of 53.50 percent. The rate review seeks recovery of $1.3 billion of net capital investment since the last general rate review. A hearing on the merits is scheduled for June 17, 2024.

SPP Proceedings

Resource Capacity Accreditation

In July 2022, the SPP Board of Directors approved a new unit accreditation methodology for conventional generation which requires submittal to and approval from the FERC prior to becoming effective. On March 2, 2023, the FERC rejected the SPP’s proposed capacity accreditation methodology for wind and solar generators. Following the FERC’s rejection, the SPP began an extensive review of both the methodology proposed for thermal resources which had not yet been submitted to the FERC, and the accreditation methodology for wind and solar generators. These methodologies were reviewed and approved by both the Regional State Committee and the SPP Board of Directors in late October 2023 and will be submitted to the FERC for approval. If approved by the FERC, both methodologies are expected to be effective in 2026 and may contribute to OG&E’s incremental capacity needs.