Regulatory Matters	3 Months Ended
Mar. 31, 2025
Regulated Operations [Abstract]
Regulatory Matters	REGULATORY MATTERS RATE-RELATED INFORMATION The NCUC, PSCSC, FPSC, IURC, PUCO, TPUC and KPSC approve rates for retail electric and natural gas services within their states. The FERC approves rates for electric sales to wholesale customers served under cost-based rates (excluding Ohio and Indiana), as well as sales of transmission service. The FERC also regulates certification and siting of new interstate natural gas pipeline projects. For open regulatory matters, unless otherwise noted, the Subsidiary Registrants and Duke Energy Kentucky cannot predict the outcome or ultimate resolution of their respective matters. Duke Energy Carolinas and Duke Energy Progress Hurricanes Debby and Helene In 2024, hurricanes Debby and Helene significantly impacted the Duke Energy Carolinas and Duke Energy Progress territories in North Carolina and South Carolina. As of March 31, 2025, the total cumulative operations and maintenance expense incurred for restoration and rebuilding of infrastructure associated with the hurricanes was approximately $764 million ($554 million and $210 million for Duke Energy Carolinas and Duke Energy Progress, respectively). The reduction in cumulative operations and maintenance expense compared to December 31, 2024, of $58 million for Duke Energy Carolinas and $38 million for Duke Energy Progress, was recorded as a reduction in Regulatory assets within Other Noncurrent Assets on the Condensed Consolidated Balance Sheets. In addition, through March 31, 2025, there have been cumulative capital investments of $556 million ($404 million and $152 million for Duke Energy Carolinas and Duke Energy Progress, respectively) associated with the hurricanes. Amounts are net of expected insurance recoveries and could change going forward as storm restoration and rebuild work is finalized. Additional estimated capital costs of approximately $100 million is expected to be incurred through the first half of 2026 to rebuild the systems from hurricane damage. North Carolina Storm Cost Securitization In December 2024, Duke Energy Carolinas and Duke Energy Progress filed their joint petition for review and approval of storm recovery costs (Phase 1) with the NCUC to securitize the North Carolina-retail allocable share of storm costs associated with hurricanes Helene, Debby and Ian, as well as Hurricane Zeta and Winter Storm Izzy, and the establishment of storm reserves for $200 million at Duke Energy Carolinas and $100 million at Duke Energy Progress. On February 3, 2025, Duke Energy Carolinas and Duke Energy Progress filed their joint petition for financing orders (Phase 2). In February 2025, Duke Energy Carolinas and Duke Energy Progress reached a settlement agreement with the North Carolina Public Staff and other intervening parties that resolved all issues between the parties in the Phase 1 proceeding and removed the establishment of storm reserves from the securitization proceeding. Further, the settlement outlined agreement on certain issues in the Phase 2 proceeding. The evidentiary hearing for Phase 1 was held on February 13, 2025. On April 16, 2025, the NCUC issued its Phase 1 order approving the settlement and determining that approximately $584 million for Duke Energy Carolinas and $461 million for Duke Energy Progress in storm recovery costs are reasonable and prudent and eligible for securitization. The order authorizes the companies to proceed to Phase 2 of the securitization process. On April 15, 2025, Duke Energy Carolinas and Duke Energy Progress filed a settlement with the North Carolina Public Staff resolving all remaining issues in Phase 2. The evidentiary hearing for Phase 2 was held on April 21, 2025, and a Phase 2 order is expected in June 2025. Subject to NCUC approval of Phase 2, Duke Energy Carolinas and Duke Energy Progress expect to securitize the North Carolina-retail allocable share of storm costs by the end of 2025. South Carolinas Storm Cost Securitization On March 21, 2025, Duke Energy Carolinas filed a petition for storm securitization with the PSCSC for authorization to finance the estimated South Carolina-retail allocable share of storm costs of $604 million primarily related to Hurricane Helene storm recovery activities and inclusive of funding $25 million related to storm reserves. On April 7, 2025, the PSCSC issued a procedural schedule, scheduling an evidentiary hearing in June 2025 and the issuance of a financing order by August 1, 2025. The petition assumes a November 30, 2025 bond issuance. Subject to PSCSC approval, Duke Energy Carolinas expects to securitize its South Carolina-retail allocable share of storm costs by the end of 2025. Due to the relatively low level of storm costs incurred by Duke Energy Progress in South Carolina, Duke Energy Progress will not seek to pursue securitization of those costs and has offset those costs against established storm reserve balances. Duke Energy Carolinas Oconee Subsequent License Renewal On June 7, 2021, Duke Energy Carolinas filed a subsequent license renewal (SLR) application for Oconee with the NRC to renew the operating licenses. On March 31, 2025, the NRC issued the subsequent renewed licenses for Oconee, allowing an additional 20 years of operation to 2053 (units 1 and 2) and 2054 (unit 3). 2023 North Carolina Rate Case In January 2023, Duke Energy Carolinas filed a performance-based regulation (PBR) application with the NCUC to request an increase in base rate retail revenues. The PBR application included a multiyear rate plan (MYRP) to recover projected capital investments during the three-year MYRP period. In addition to the MYRP, the PBR application included an Earnings Sharing Mechanism, Residential Decoupling Mechanism and Performance Incentive Mechanisms (PIMS) as required by HB 951. In August 2023, Duke Energy Carolinas filed with the NCUC a partial settlement with the North Carolina Public Staff in connection with its PBR application. The partial settlement included, among other things, agreement on a substantial portion of the North Carolina retail rate base for the historic base case of approximately $19.5 billion and all of the capital projects and related costs to be included in the three-year MYRP, including $4.6 billion (North Carolina retail allocation) projected to go in service over the MYRP period. Additionally, the partial settlement included agreement, with certain adjustments, on depreciation rates, the recovery of grid improvement plan costs and PIMs, Tracking Metrics and the Residential Decoupling Mechanism under the PBR application. On August 28, 2023, Duke Energy Carolinas filed with the NCUC a second partial settlement with the North Carolina Public Staff resolving additional issues, including the future treatment of nuclear PTCs related to the IRA, through a stand-alone rider that would provide the benefits to customers. This stand-alone rider was effective in rates beginning January 1, 2025. On December 15, 2023, the NCUC issued an order approving Duke Energy Carolinas' PBR application, as modified by the partial settlements and the order, including an overall retail revenue increase of $436 million in Year 1, $174 million in Year 2 and $158 million in Year 3, for a combined total of $768 million. The order established an ROE of 10.1% based upon an equity ratio of 53% and approved, with certain adjustments, depreciation rates and the recovery of grid improvement plan costs and certain deferred COVID-related costs. Additionally, the Residential Decoupling Mechanism and PIMs were approved as requested under the PBR application and revised by the partial settlements. Duke Energy Carolinas implemented interim rates on September 1, 2023. New revised Year 1 rates and the residential decoupling were implemented on January 15, 2024. In February 2024, a number of parties filed Notices of Appeal of the December 15, 2023, NCUC order. Notices of Appeal were filed by the Carolina Industrial Group for Fair Utility Rates (CIGFUR) III, a collection of electric membership cooperatives (collectively, the EMCs), and the North Carolina Attorney General’s Office (the AGO). CIGFUR III and the EMCs appealed the interclass subsidy reduction percentage and the Transmission Cost Allocation stipulation. In addition, CIGFUR III appealed the NCUC’s elimination of the equal percentage fuel cost allocation methodology. The AGO appealed several issues including the authorized ROE and certain rate design and accounting matters. On March 1, 2024, Carolina Utility Customers Association, Inc. appealed several issues, including the authorized ROE and certain rate design and accounting matters. In July 2024, the Supreme Court of North Carolina consolidated these appeals with the parallel appeals of the NCUC's order regarding the Duke Energy Progress PBR application. Briefing is complete and oral arguments occurred on February 13, 2025. Duke Energy Carolinas anticipates a decision to be issued no later than the fourth quarter of 2025. Duke Energy Progress 2022 North Carolina Rate Case In October 2022, Duke Energy Progress filed a PBR application with the NCUC to request an increase in base rate retail revenues. The rate request before the NCUC included an MYRP to recover projected capital investments during the three-year MYRP period. In addition to the MYRP, the PBR application included an Earnings Sharing Mechanism, Residential Decoupling Mechanism and PIMs as required by HB 951. In April 2023, Duke Energy Progress filed with the NCUC a partial settlement with North Carolina Public Staff, which included agreement on many aspects of Duke Energy Progress' three-year MYRP proposal. In May 2023, CIGFUR II joined this partial settlement and North Carolina Public Staff and CIGFUR II filed a separate settlement reaching agreement on PIMs, Tracking Metrics and the Residential Decoupling Mechanism under the PBR application. On August 18, 2023, the NCUC issued an order approving Duke Energy Progress' PBR application, as modified by the partial settlements and the order, including an overall retail revenue increase of $233 million in Year 1, $126 million in Year 2 and $135 million in Year 3, for a combined total of $494 million. Key aspects of the order include the approval of North Carolina retail rate base for the historic base case of approximately $12.2 billion and capital projects and related costs to be included in the three-year MYRP, including $3.5 billion (North Carolina retail allocation) projected to go in service over the MYRP period. The order established an ROE of 9.8% based upon an equity ratio of 53% and approved, with certain adjustments, depreciation rates and the recovery of grid improvement plan costs and certain deferred COVID-related costs. Additionally, the Residential Decoupling Mechanism and PIMs were approved as requested under the PBR application and revised by the partial settlements. Duke Energy Progress implemented interim rates on June 1, 2023, and implemented revised Year 1 rates and the residential decoupling on October 1, 2023. In October 2023, CIGFUR II and Haywood Electric Membership Corporation each filed a Notice of Appeal of the August 18, 2023 NCUC order. Both parties are appealing certain matters that do not impact the overall revenue requirement in the rate case. Specifically, they appealed the interclass subsidy reduction percentage, and CIGFUR II also appealed the Customer Assistance Program and the equal percentage fuel cost allocation methodology. In November 2023, the AGO filed a Notice of Cross Appeal of the NCUC's determination regarding the exclusion of electric vehicle revenue from the residential decoupling mechanism. In November 2023, Duke Energy Progress, the North Carolina Public Staff, CIGFUR II, and a number of other parties reached a settlement pursuant to which CIGFUR II agreed not to pursue its appeal of the Customer Assistance Program. In July 2024, the Supreme Court of North Carolina consolidated these appeals with the parallel appeals of the NCUC's order regarding the Duke Energy Carolinas PBR application. Briefing is complete and oral arguments occurred in February 2025. Duke Energy Progress anticipates a decision to be issued no later than the fourth quarter of 2025. Person County Combined Cycle CPCN On February 7, 2025, Duke Energy Progress filed with the NCUC its application to construct and operate a second 1,360-MW hydrogen-capable, advanced-class CC unit in Person County at the Roxboro Plant. NCEMC has also notified Duke Energy Progress of NCEMC's intent to co-own approximately 225 MW of the second CC and Duke Energy Progress and NCEMC plan to begin negotiations on the contractual arrangement in the second quarter of 2025. NCEMC has the right to co-own the facility under its existing supply agreement with Duke Energy Progress. Pending regulatory approvals, construction of the second CC is planned to start in 2026 with the unit targeted to be placed in service by the end of 2029. As part of the application, Duke Energy Progress noted that the recovery of Construction Work in Progress during the construction period for the proposed facility may be pursued in a future rate case. The 2030 North Carolina retail revenue requirement for the proposed facility is estimated to be $113 million, representing an approximate average retail rate increase of 2.6% across all classes. The air permit issued by the NCDEQ in December 2024, also pertains to the second CC. An evidentiary hearing related to the CPCN is scheduled to begin on July 22, 2025. An order is expected by the end of 2025. Robinson Subsequent License Renewal On April 8, 2025, Duke Energy Progress filed an SLR application for Robinson with the NRC to renew Robinson’s operating license for an additional 20 years. The SLR would extend operations of the facility from 60 to 80 years. The current license expires in 2030. Duke Energy Florida Clean Energy Connection In July 2020, Duke Energy Florida petitioned the FPSC for approval of a voluntary solar program consisting of 10 new solar generating facilities with combined capacity of 749 MW. The FPSC approved the program in January 2021, allowing participants to support cost-effective solar development in Florida by paying a subscription fee based on per kilowatt subscriptions and receiving a credit on their bill based on the actual generation associated with their portion of the solar portfolio. The 10 new solar generation facilities were completed and all of the remaining sites were in service by the end of 2024 at a cost of approximately $1.1 billion. These investments are included in base rates offset by the revenue from the subscription fees, with credits included in the fuel cost recovery clause. In February 2021, the League of United Latin American Citizens (LULAC) filed a notice of appeal of the FPSC’s order approving the Clean Energy Connection to the Supreme Court of Florida. The Supreme Court of Florida heard oral arguments in the appeal in February 2022. On May 27, 2022, the Supreme Court of Florida issued an order remanding the case back to the FPSC so that the FPSC can amend its order to better address some of the arguments raised by LULAC. In September 2022, the FPSC issued a revised order and submitted it to the Supreme Court of Florida. The Supreme Court of Florida requested that the parties file supplemental briefs regarding the revised order, which were filed in February 2023. LULAC has filed a request for Oral Argument on the issues discussed in the supplemental briefs, but the court has yet to rule on that request. The FPSC approval order remains in effect pending the outcome of the appeal. Storm Protection Plan At least every three years, Duke Energy Florida must file a Storm Protection Plan (SPP) with the FPSC. Each plan covers a 10-year period and includes investments in transmission and distribution meant to strengthen infrastructure, reduce outage times associated with extreme weather events, reduce restoration costs and improve overall service reliability. In April 2022, Duke Energy Florida filed an SPP for approval with the FPSC for the 2023-2032 time frame. The plan reflected approximately $7 billion of capital investment in transmission and distribution. The evidentiary hearing began in August 2022. In October 2022, the FPSC approved Duke Energy Florida’s plan with one modification to remove the transmission loop radially fed program, representing a reduction of approximately $80 million over the 10-year period starting in 2025. In December 2022, the OPC filed a notice of appeal of this order to the Florida Supreme Court and briefs were filed by the OPC and Duke Energy Florida during 2023. On November 14, 2024, the Florida Supreme Court issued an order upholding the FPSC's approval of Duke Energy Florida's plan. In January 2025, Duke Energy Florida filed an SPP for approval with the FPSC for the 2026-2035 time frame reflecting approximately $7 billion of capital investment in transmission and distribution. On March 12, 2025, the OPC filed testimony recommending that the pace of the proposed spend be reduced, as well as challenging three subprograms in Duke Energy Florida's SPP. Duke Energy Florida filed rebuttal testimony on April 2, 2025, requesting that the FPSC approve its SPP as filed. The FPSC must approve, with or without modification, or deny the plan no later than July 15, 2025. A hearing has been scheduled to begin May 20, 2025. Hurricanes Debby, Helene and Milton In 2024, Hurricane Debby (Category 1 storm), Hurricane Helene (Category 4 storm) and Hurricane Milton (Category 3 storm) made landfall in Florida and caused significant damage. Duke Energy Florida has certain existing storm reserve regulatory liability amounts, which are applied to the recovery of storm costs. The storm reserve amount was approximately $63 million as of July 31, 2024, prior to the damage resulting from hurricanes Debby, Helene and Milton. Duke Energy Florida is permitted to petition the FPSC for recovery of incremental operation and maintenance costs resulting from the storms and to replenish the retail customer storm reserve to approximately $132 million. In December 2024, Duke Energy Florida filed its petition to recover the estimated costs incurred to respond to all three storms, including replenishment of the storm reserve, seeking recovery of approximately $1.1 billion over 12 months beginning with the first billing cycle in March 2025. Approximately $813 million and $936 million of the operation and maintenance expenses, net of storm reserves, are deferred in Regulatory assets within Current assets as of March 31, 2025, and December 31, 2024, respectively. Approximately $74 million of capital related to these storms will be sought for recovery in future base rate case filings. On February 4, 2025, the FPSC voted to approve Duke Energy Florida's request for recovery of these estimated storm costs as filed, subject to true-up after the actual costs are filed. New rates were effective March 1, 2025. Duke Energy Ohio Duke Energy Ohio Natural Gas Base Rate Case In June 2022, Duke Energy Ohio filed a natural gas base rate case application with the PUCO. The drivers for this case were capital invested since Duke Energy Ohio's last natural gas base rate case in 2012. Duke Energy Ohio also sought to adjust the caps on its Capital Expenditure Program (CEP) rider. In April 2023, Duke Energy Ohio filed a stipulation with all parties to the case except the OCC. In the stipulation, the parties agreed to approximately $32 million in revenue increases with an equity ratio of 52.32% and an ROE of 9.6%, and adjustments to the CEP Rider caps. The stipulation was opposed by the OCC at an evidentiary hearing that concluded in May 2023. On November 1, 2023, PUCO issued an order approving the stipulation as filed and new rates went into effect November 1, 2023. In December 2023, the OCC filed an application for rehearing and the PUCO granted OCC's application for rehearing for further consideration of issues raised. As a result of a Supreme Court of Ohio decision regarding procedural issues related to applications for rehearing, PUCO denied OCC’s rehearing request. In October 2024, the OCC filed its Notice of Appeal with the Ohio Supreme Court. The case is fully briefed, and oral argument is expected to be scheduled to occur during the third quarter of 2025. Duke Energy Ohio Electric Security Plan In April 2024, Duke Energy Ohio filed with the PUCO a request for an Electric Security Plan (ESP). The ESP application proposed a three-year term from June 1, 2025, through May 31, 2028, and included continuation of market-based rates for generation supply through competitive procurement processes and continuation and expansion of existing rider mechanisms. Duke Energy Ohio proposed a new rider mechanism relating to electric distribution infrastructure modernization programs, which may be enabled by and partially funded through federal or state funding opportunities, as well as future battery storage projects and two electric vehicle programs. Additional proposals included new rider mechanisms related to solar for all investments for low-income and disadvantaged communities, low-income senior citizen bill assistance, and energy efficiency (EE) and demand-side management programs. In November 2024, Duke Energy Ohio filed a stipulation that the majority of the intervenors signed as either signatory or non-opposing parties. The stipulation includes the continuation of market-based customer rates for generation supply through competitive procurement auctions and the continuation of all existing riders. It further establishes new caps for certain riders. Duke Energy Ohio also agreed to withdraw its proposals for an infrastructure modernization rider, battery storage projects and electric vehicle programs. The stipulation includes a residential EE program with provisions for low-income customers. The evidentiary hearing concluded in January 2025 and the case was fully briefed on March 14, 2025. On April 30, 2025, Ohio Substitute House Bill 15 (HB 15) was passed and sent to the governor of Ohio. HB 15 will be effective 90 days after approval by the governor or the expiration of a 10-day review period if the governor takes no action. Duke Energy Ohio anticipates HB 15 will become law by August 10, 2025. HB 15 requires electric distribution utilities to file a base rate case every three years, commencing no later than December 31, 2029, and establishes an opportunity to apply for approval of a three-year rate plan with forward-looking test periods to mitigate regulatory lag. HB 15 eliminates ESPs and certain distribution-related riders, but permits ESPs approved as of the effective date of HB 15 to remain in place through the end of their authorized term. HB 15 also eliminates Duke Energy Ohio's Legacy Generation Rider (LGR) upon the effective date of HB 15 and prevents the PUCO from future reauthorization of similar arrangements. As a result of HB 15, any future losses related to Duke Energy Ohio's Inter-Company Power Agreement with OVEC will not be recoverable from retail customers. Additionally, regulatory assets related to OVEC at the time of HB 15 becoming effective may not be recoverable. Regulatory assets related to OVEC were $24 million and $30 million as of March 31, 2025, and December 31, 2024, respectively. Duke Energy Kentucky 2022 Electric Base Rate Case In December 2022, Duke Energy Kentucky filed a rate case with the KPSC driven by capital investments to strengthen the electricity generation and delivery systems along with adjusted depreciation rates for the East Bend and Woodsdale Combustion Turbine (CT) generation stations. Duke Energy Kentucky also requested approval for new programs and tariff updates, including a voluntary community-based renewable subscription program and two electric vehicle charging programs. The KPSC issued an order on October 12, 2023, including a $48 million increase in base revenues, an ROE of 9.75% for electric base rates and 9.65% for electric riders and an equity ratio of 52.145%. New rates went into effect October 13, 2023. Duke Energy Kentucky's request to align the depreciation rates of East Bend with a 2035 retirement date was denied and the KPSC ordered depreciation rates with a 2041 retirement date for the unit. The KPSC did approve the request to align the depreciation rates of Woodsdale CT with a 2040 retirement date and denied the voluntary community-based renewable subscription program and the two electric vehicle charging programs. In November 2023, Duke Energy Kentucky filed for rehearing requesting certain matters be reconsidered by the KPSC and the KPSC granted in part and denied in part Duke Energy Kentucky's request for rehearing. On July 1, 2024, the KPSC issued its final order on rehearing, ruling in Duke Energy Kentucky's favor on nearly all issues. However, the KPSC ordered Duke Energy Kentucky to refund alleged over collections since the KPSC order on October 12, 2023. On July 10, 2024, the KPSC issued an order correcting the base fuel rate used to calculate new base rates in its July 1, 2024 order and its calculation of Duke Energy Kentucky's Street Lighting Rate. New rates were implemented in August 2024. On December 14, 2023, Duke Energy Kentucky filed an appeal with the Franklin County Circuit Court on certain matters for which the KPSC denied rehearing, specifically as it relates to including decommissioning costs in depreciation rates for East Bend and Woodsdale. Duke Energy Kentucky and Appellee briefs were filed in 2024. Duke Energy Kentucky 2024 Electric Base Rate Case In December 2024, Duke Energy Kentucky filed a base rate case with the KPSC requesting an annualized increase in electric base rates of approximately $70 million and an ROE of 10.85% with an equity ratio of 52.728%. This is an overall increase of approximately 14.7%. The request for the rate increase is driven by capital investments to strengthen the electricity generation and delivery systems. New rates are anticipated to go into effect around July 2, 2025. An evidentiary hearing is scheduled to begin on May 21, 2025. Duke Energy Indiana Indiana Coal Ash Recovery In Duke Energy Indiana’s 2019 rate case, the IURC also opened a subdocket for post-2018 coal ash related expenditures. Duke Energy Indiana filed testimony in April 2020, in the coal ash subdocket requesting recovery for the post-2018 coal ash basin closure costs for plans that have been approved by the Indiana Department of Environmental Management (IDEM) as well as continuing deferral, with carrying costs, on the balance of such coal ash basin closure costs. On November 3, 2021, the IURC issued an order allowing recovery for post-2018 coal ash basin closure costs for the plans that have been approved by IDEM, as well as continuing deferral, with carrying costs, on the balance. The OUCC and the Duke Industrial Group appealed. The Indiana Court of Appeals issued its opinion on February 21, 2023, reversing the IURC's order to the extent that it allowed Duke Energy Indiana to recover federally mandated costs incurred prior to the IURC's November 3, 2021 order. In addition, the court found that any costs incurred pre-petition to determine federally mandated compliance options were not specifically authorized by the statute and should also be disallowed. In 2023, Duke Energy Indiana filed its proposal to remove from rates certain costs incurred prior to the IURC's November 3, 2021 order date. On September 20, 2023, the IURC approved Duke Energy Indiana's proposal to remove the costs from its rates and assessed simple interest of the refunds of 4.71%, beginning from when the costs were initially recovered from customers. Duke Energy Indiana included a request to recover the pre-order costs denied by the Indiana Court of Appeals and certain future coal ash closure costs as part of depreciation costs in the 2024 Indiana Rate Case. In 2023, Duke Energy Indiana filed a petition under the amended version of the federal mandate statute for additional post-2018 coal ash closure costs for the remaining basins not included in the Indiana coal ash recovery case from 2020. On May 8, 2024, the IURC issued a CPCN and approved these coal ash related compliance projects as federally mandated compliance projects. In June 2024, the Citizens Action Coalition of Indiana (CAC) filed a motion to appeal the IURC order granting the coal ash CPCN proceeding and approving the coal ash related compliance projects. Briefing was completed in January 2025, and Duke Energy Indiana is awaiting an opinion from the appellate court. TDSIC 2.0 In November 2021, Duke Energy Indiana filed for approval of the Transmission, Distribution, Storage Improvement Charge 2.0 investment plan for 2023-2028 (TDSIC 2.0). On June 15, 2022, the IURC approved, without modification, TDSIC 2.0, which includes approximately $2 billion in transmission and distribution investments selected to improve customer reliability, harden and improve resiliency of the grid, enable expansion of renewable and distributed energy projects and encourage economic development. In July 2022, the OUCC filed a notice of appeal to the Indiana Court of Appeals in Duke Energy Indiana’s TDSIC 2.0 proceeding. The Indiana Court of Appeals issued its opinion on March 9, 2023, affirming the IURC’s order in its entirety. The Duke Industrial Group filed a petition to transfer to the Indiana Supreme Court. On December 19, 2024, the Indiana Supreme Court affirmed the Indiana Court of Appeals decision, concluding there was substantial evidence that the IURC's conclusion was reasonable and the TDSIC 2.0 plan met the statutory requirements. On January 21, 2025, the Duke Industrial Group filed a motion for rehearing. On March 4, 2025, the Indiana Supreme Court denied the Duke Industrial Group's petition for rehearing. There can be no further appeals on TDSIC 2.0 and this matter is now fully resolved. 2024 Indiana Rate Case In April 2024, Duke Energy Indiana filed an application with the IURC for a rate increase of $492 million, representing an overall average bill increase of approximately 16.2%, which, if approved, would be added to retail customer bills in two steps, approximately 11.7% in 2025 and approximately 4.5% in 2026. Duke Energy Indiana requested an ROE of 10.5% with an equity ratio of 53%. The rate increase is driven by $1.6 billion in investments made since the last general rate case filed in 2019 in order to reliably serve customers, improve resiliency of the system, and advance environmental sustainability. An order for the rate case was issued by the IURC on January 29, 2025, and revised February 3, 2025, which authorized an ROE of 9.75%, an equity ratio of 53% and an annual revenue increase of $296 million. Based on review of these orders, Duke Energy Indiana identified an inconsistency in the calculation of operating revenues before the effect of trackers. On February 7, 2025, Duke Energy Indiana made a compliance filing in accordance with the IURC's findings in its order and addressed the identified inconsistencies. The compliance filing also clarified the annual revenue increase was approximately $385 million. Additionally, on February 18, 2025, one industrial customer submitted a filing requesting the IURC to clarify its revenue allocation in these proceedings, which was denied by the Commission on April 16, 2025. On February 25, 2025, the IURC approved Duke Energy Indiana’s compliance filing and new rates were implemented February 27, 2025. The industrial customer filed a notice of appeal on February 28, 2025, regarding cost of service allocation. On April 9, 2025, the IURC issued an order correcting its January 29, 2025 order to apply a rate migration adjustment to industrial customers. An industrial customer appealed the IURC order to the Indiana Court of Appeals, but this appeal has been stayed. Cayuga Combined Cycle CPCN On February 13, 2025, Duke Energy Indiana filed for a CPCN seeking approval to construct two 1x1 CC natural gas-fired units with a combined winter rating of 1,476 MW. The Cayuga CC Project is proposed to be constructed on the same site as the retiring Cayuga coal-fired steam units with a winter rating of 1,005 MW. The Cayuga CC Project will result in an incremental 471 MW for the Duke Energy Indiana system and will allow Duke Energy Indiana to avoid expected maintenance and environmental compliance costs needed for the coal units to continue operating. The estimated cost of the Cayuga CC project is approximately $3 billion, plus AFUDC and project reserves. Duke Energy Indiana has proposed recovery of certain facility costs during construction, including AFUDC, through construction work in progress ratemaking via a proposed generation cost adjustment tracker mechanism. The estimated average retail rate impact during construction and initial in-service periods from April 2026 through May 2031 is approximately 5.4%. Duke Energy Indiana expects CC 1 to be placed in service in 2029 and CC 2 to be placed in service in 2030. A final air permit was issued by IDEM on March 5, 2025. An evidentiary hearing related to the CPCN is scheduled to begin on June 19, 2025. An order is expected by October 2025.

The NCUC, PSCSC, FPSC, IURC, PUCO, TPUC and KPSC approve rates for retail electric and natural gas services within their states. The FERC approves rates for electric sales to wholesale customers served under cost-based rates (excluding Ohio and Indiana), as well as sales of transmission service. The FERC also regulates certification and siting of new interstate natural gas pipeline projects. For open regulatory matters, unless otherwise noted, the Subsidiary Registrants and Duke Energy Kentucky cannot predict the outcome or ultimate resolution of their respective matters.

In 2024, hurricanes Debby and Helene significantly impacted the Duke Energy Carolinas and Duke Energy Progress territories in North Carolina and South Carolina. As of March 31, 2025, the total cumulative operations and maintenance expense incurred for restoration and rebuilding of infrastructure associated with the hurricanes was approximately $764 million ($554 million and $210 million for Duke Energy Carolinas and Duke Energy Progress, respectively). The reduction in cumulative operations and maintenance expense compared to December 31, 2024, of $58 million for Duke Energy Carolinas and $38 million for Duke Energy Progress, was recorded as a reduction in Regulatory assets within Other Noncurrent Assets on the Condensed Consolidated Balance Sheets. In addition, through March 31, 2025, there have been cumulative capital investments of $556 million ($404 million and $152 million for Duke Energy Carolinas and Duke Energy Progress, respectively) associated with the hurricanes. Amounts are net of expected insurance recoveries and could change going forward as storm restoration and rebuild work is finalized. Additional estimated capital costs of approximately $100 million is expected to be incurred through the first half of 2026 to rebuild the systems from hurricane damage.

In December 2024, Duke Energy Carolinas and Duke Energy Progress filed their joint petition for review and approval of storm recovery costs (Phase 1) with the NCUC to securitize the North Carolina-retail allocable share of storm costs associated with hurricanes Helene, Debby and Ian, as well as Hurricane Zeta and Winter Storm Izzy, and the establishment of storm reserves for $200 million at Duke Energy Carolinas and $100 million at Duke Energy Progress. On February 3, 2025, Duke Energy Carolinas and Duke Energy Progress filed their joint petition for financing orders (Phase 2). In February 2025, Duke Energy Carolinas and Duke Energy Progress reached a settlement agreement with the North Carolina Public Staff and other intervening parties that resolved all issues between the parties in the Phase 1 proceeding and removed the establishment of storm reserves from the securitization proceeding. Further, the settlement outlined agreement on certain issues in the Phase 2 proceeding. The evidentiary hearing for Phase 1 was held on February 13, 2025.

On April 16, 2025, the NCUC issued its Phase 1 order approving the settlement and determining that approximately $584 million for Duke Energy Carolinas and $461 million for Duke Energy Progress in storm recovery costs are reasonable and prudent and eligible for securitization. The order authorizes the companies to proceed to Phase 2 of the securitization process. On April 15, 2025, Duke Energy Carolinas and Duke Energy Progress filed a settlement with the North Carolina Public Staff resolving all remaining issues in Phase 2. The evidentiary hearing for Phase 2 was held on April 21, 2025, and a Phase 2 order is expected in June 2025. Subject to NCUC approval of Phase 2, Duke Energy Carolinas and Duke Energy Progress expect to securitize the North Carolina-retail allocable share of storm costs by the end of 2025.

On March 21, 2025, Duke Energy Carolinas filed a petition for storm securitization with the PSCSC for authorization to finance the estimated South Carolina-retail allocable share of storm costs of $604 million primarily related to Hurricane Helene storm recovery activities and inclusive of funding $25 million related to storm reserves. On April 7, 2025, the PSCSC issued a procedural schedule, scheduling an evidentiary hearing in June 2025 and the issuance of a financing order by August 1, 2025. The petition assumes a November 30, 2025 bond issuance. Subject to PSCSC approval, Duke Energy Carolinas expects to securitize its South Carolina-retail allocable share of storm costs by the end of 2025. Due to the relatively low level of storm costs incurred by Duke Energy Progress in South Carolina, Duke Energy Progress will not seek to pursue securitization of those costs and has offset those costs against established storm reserve balances.

On June 7, 2021, Duke Energy Carolinas filed a subsequent license renewal (SLR) application for Oconee with the NRC to renew the operating licenses. On March 31, 2025, the NRC issued the subsequent renewed licenses for Oconee, allowing an additional 20 years of operation to 2053 (units 1 and 2) and 2054 (unit 3).

In January 2023, Duke Energy Carolinas filed a performance-based regulation (PBR) application with the NCUC to request an increase in base rate retail revenues. The PBR application included a multiyear rate plan (MYRP) to recover projected capital investments during the three-year MYRP period. In addition to the MYRP, the PBR application included an Earnings Sharing Mechanism, Residential Decoupling Mechanism and Performance Incentive Mechanisms (PIMS) as required by HB 951.

In August 2023, Duke Energy Carolinas filed with the NCUC a partial settlement with the North Carolina Public Staff in connection with its PBR application. The partial settlement included, among other things, agreement on a substantial portion of the North Carolina retail rate base for the historic base case of approximately $19.5 billion and all of the capital projects and related costs to be included in the three-year MYRP, including $4.6 billion (North Carolina retail allocation) projected to go in service over the MYRP period. Additionally, the partial settlement included agreement, with certain adjustments, on depreciation rates, the recovery of grid improvement plan costs and PIMs, Tracking Metrics and the Residential Decoupling Mechanism under the PBR application. On August 28, 2023, Duke Energy Carolinas filed with the NCUC a second partial settlement with the North Carolina Public Staff resolving additional issues, including the future treatment of nuclear PTCs related to the IRA, through a stand-alone rider that would provide the benefits to customers. This stand-alone rider was effective in rates beginning January 1, 2025.

On December 15, 2023, the NCUC issued an order approving Duke Energy Carolinas' PBR application, as modified by the partial settlements and the order, including an overall retail revenue increase of $436 million in Year 1, $174 million in Year 2 and $158 million in Year 3, for a combined total of $768 million. The order established an ROE of 10.1% based upon an equity ratio of 53% and approved, with certain adjustments, depreciation rates and the recovery of grid improvement plan costs and certain deferred COVID-related costs. Additionally, the Residential Decoupling Mechanism and PIMs were approved as requested under the PBR application and revised by the partial settlements. Duke Energy Carolinas implemented interim rates on September 1, 2023. New revised Year 1 rates and the residential decoupling were implemented on January 15, 2024.

In February 2024, a number of parties filed Notices of Appeal of the December 15, 2023, NCUC order. Notices of Appeal were filed by the Carolina Industrial Group for Fair Utility Rates (CIGFUR) III, a collection of electric membership cooperatives (collectively, the EMCs), and the North Carolina Attorney General’s Office (the AGO). CIGFUR III and the EMCs appealed the interclass subsidy reduction percentage and the Transmission Cost Allocation stipulation. In addition, CIGFUR III appealed the NCUC’s elimination of the equal percentage fuel cost allocation methodology. The AGO appealed several issues including the authorized ROE and certain rate design and accounting matters. On March 1, 2024, Carolina Utility Customers Association, Inc. appealed several issues, including the authorized ROE and certain rate design and accounting matters. In July 2024, the Supreme Court of North Carolina consolidated these appeals with the parallel appeals of the NCUC's order regarding the Duke Energy Progress PBR application. Briefing is complete and oral arguments occurred on February 13, 2025. Duke Energy Carolinas anticipates a decision to be issued no later than the fourth quarter of 2025.

In October 2022, Duke Energy Progress filed a PBR application with the NCUC to request an increase in base rate retail revenues. The rate request before the NCUC included an MYRP to recover projected capital investments during the three-year MYRP period. In addition to the MYRP, the PBR application included an Earnings Sharing Mechanism, Residential Decoupling Mechanism and PIMs as required by HB 951.

In April 2023, Duke Energy Progress filed with the NCUC a partial settlement with North Carolina Public Staff, which included agreement on many aspects of Duke Energy Progress' three-year MYRP proposal. In May 2023, CIGFUR II joined this partial settlement and North Carolina Public Staff and CIGFUR II filed a separate settlement reaching agreement on PIMs, Tracking Metrics and the Residential Decoupling Mechanism under the PBR application.

On August 18, 2023, the NCUC issued an order approving Duke Energy Progress' PBR application, as modified by the partial settlements and the order, including an overall retail revenue increase of $233 million in Year 1, $126 million in Year 2 and $135 million in Year 3, for a combined total of $494 million. Key aspects of the order include the approval of North Carolina retail rate base for the historic base case of approximately $12.2 billion and capital projects and related costs to be included in the three-year MYRP, including $3.5 billion (North Carolina retail allocation) projected to go in service over the MYRP period. The order established an ROE of 9.8% based upon an equity ratio of 53% and approved, with certain adjustments, depreciation rates and the recovery of grid improvement plan costs and certain deferred COVID-related costs. Additionally, the Residential Decoupling Mechanism and PIMs were approved as requested under the PBR application and revised by the partial settlements. Duke Energy Progress implemented interim rates on June 1, 2023, and implemented revised Year 1 rates and the residential decoupling on October 1, 2023.

In October 2023, CIGFUR II and Haywood Electric Membership Corporation each filed a Notice of Appeal of the August 18, 2023 NCUC order. Both parties are appealing certain matters that do not impact the overall revenue requirement in the rate case. Specifically, they appealed the interclass subsidy reduction percentage, and CIGFUR II also appealed the Customer Assistance Program and the equal percentage fuel cost allocation methodology. In November 2023, the AGO filed a Notice of Cross Appeal of the NCUC's determination regarding the exclusion of electric vehicle revenue from the residential decoupling mechanism. In November 2023, Duke Energy Progress, the North Carolina Public Staff, CIGFUR II, and a number of other parties reached a settlement pursuant to which CIGFUR II agreed not to pursue its appeal of the Customer Assistance Program. In July 2024, the Supreme Court of North Carolina consolidated these appeals with the parallel appeals of the NCUC's order regarding the Duke Energy Carolinas PBR application. Briefing is complete and oral arguments occurred in February 2025. Duke Energy Progress anticipates a decision to be issued no later than the fourth quarter of 2025.

On February 7, 2025, Duke Energy Progress filed with the NCUC its application to construct and operate a second 1,360-MW hydrogen-capable, advanced-class CC unit in Person County at the Roxboro Plant. NCEMC has also notified Duke Energy Progress of NCEMC's intent to co-own approximately 225 MW of the second CC and Duke Energy Progress and NCEMC plan to begin negotiations on the contractual arrangement in the second quarter of 2025. NCEMC has the right to co-own the facility under its existing supply agreement with Duke Energy Progress. Pending regulatory approvals, construction of the second CC is planned to start in 2026 with the unit targeted to be placed in service by the end of 2029. As part of the application, Duke Energy Progress noted that the recovery of Construction Work in Progress during the construction period for the proposed facility may be pursued in a future rate case. The 2030 North Carolina retail revenue requirement for the proposed facility is estimated to be $113 million, representing an approximate average retail rate increase of 2.6% across all classes. The air permit issued by the NCDEQ in December 2024, also pertains to the second CC. An evidentiary hearing related to the CPCN is scheduled to begin on July 22, 2025. An order is expected by the end of 2025.

In July 2020, Duke Energy Florida petitioned the FPSC for approval of a voluntary solar program consisting of 10 new solar generating facilities with combined capacity of 749 MW. The FPSC approved the program in January 2021, allowing participants to support cost-effective solar development in Florida by paying a subscription fee based on per kilowatt subscriptions and receiving a credit on their bill based on the actual generation associated with their portion of the solar portfolio. The 10 new solar generation facilities were completed and all of the remaining sites were in service by the end of 2024 at a cost of approximately $1.1 billion. These investments are included in base rates offset by the revenue from the subscription fees, with credits included in the fuel cost recovery clause.

In February 2021, the League of United Latin American Citizens (LULAC) filed a notice of appeal of the FPSC’s order approving the Clean Energy Connection to the Supreme Court of Florida. The Supreme Court of Florida heard oral arguments in the appeal in February 2022. On May 27, 2022, the Supreme Court of Florida issued an order remanding the case back to the FPSC so that the FPSC can amend its order to better address some of the arguments raised by LULAC. In September 2022, the FPSC issued a revised order and submitted it to the Supreme Court of Florida. The Supreme Court of Florida requested that the parties file supplemental briefs regarding the revised order, which were filed in February 2023. LULAC has filed a request for Oral Argument on the issues discussed in the supplemental briefs, but the court has yet to rule on that request. The FPSC approval order remains in effect pending the outcome of the appeal.

At least every three years, Duke Energy Florida must file a Storm Protection Plan (SPP) with the FPSC. Each plan covers a 10-year period and includes investments in transmission and distribution meant to strengthen infrastructure, reduce outage times associated with extreme weather events, reduce restoration costs and improve overall service reliability. In April 2022, Duke Energy Florida filed an SPP for approval with the FPSC for the 2023-2032 time frame. The plan reflected approximately $7 billion of capital investment in transmission and distribution. The evidentiary hearing began in August 2022. In October 2022, the FPSC approved Duke Energy Florida’s plan with one modification to remove the transmission loop radially fed program, representing a reduction of approximately $80 million over the 10-year period starting in 2025. In December 2022, the OPC filed a notice of appeal of this order to the Florida Supreme Court and briefs were filed by the OPC and Duke Energy Florida during 2023. On November 14, 2024, the Florida Supreme Court issued an order upholding the FPSC's approval of Duke Energy Florida's plan.

In January 2025, Duke Energy Florida filed an SPP for approval with the FPSC for the 2026-2035 time frame reflecting approximately $7 billion of capital investment in transmission and distribution. On March 12, 2025, the OPC filed testimony recommending that the pace of the proposed spend be reduced, as well as challenging three subprograms in Duke Energy Florida's SPP. Duke Energy Florida filed rebuttal testimony on April 2, 2025, requesting that the FPSC approve its SPP as filed. The FPSC must approve, with or without modification, or deny the plan no later than July 15, 2025. A hearing has been scheduled to begin May 20, 2025.

In 2024, Hurricane Debby (Category 1 storm), Hurricane Helene (Category 4 storm) and Hurricane Milton (Category 3 storm) made landfall in Florida and caused significant damage. Duke Energy Florida has certain existing storm reserve regulatory liability amounts, which are applied to the recovery of storm costs. The storm reserve amount was approximately $63 million as of July 31, 2024, prior to the damage resulting from hurricanes Debby, Helene and Milton. Duke Energy Florida is permitted to petition the FPSC for recovery of incremental operation and maintenance costs resulting from the storms and to replenish the retail customer storm reserve to approximately $132 million.

In December 2024, Duke Energy Florida filed its petition to recover the estimated costs incurred to respond to all three storms, including replenishment of the storm reserve, seeking recovery of approximately $1.1 billion over 12 months beginning with the first billing cycle in March 2025. Approximately $813 million and $936 million of the operation and maintenance expenses, net of storm reserves, are deferred in Regulatory assets within Current assets as of March 31, 2025, and December 31, 2024, respectively. Approximately $74 million of capital related to these storms will be sought for recovery in future base rate case filings. On February 4, 2025, the FPSC voted to approve Duke Energy Florida's request for recovery of these estimated storm costs as filed, subject to true-up after the actual costs are filed. New rates were effective March 1, 2025.

In June 2022, Duke Energy Ohio filed a natural gas base rate case application with the PUCO. The drivers for this case were capital invested since Duke Energy Ohio's last natural gas base rate case in 2012. Duke Energy Ohio also sought to adjust the caps on its Capital Expenditure Program (CEP) rider. In April 2023, Duke Energy Ohio filed a stipulation with all parties to the case except the OCC. In the stipulation, the parties agreed to approximately $32 million in revenue increases with an equity ratio of 52.32% and an ROE of 9.6%, and adjustments to the CEP Rider caps. The stipulation was opposed by the OCC at an evidentiary hearing that concluded in May 2023. On November 1, 2023, PUCO issued an order approving the stipulation as filed and new rates went into effect November 1, 2023. In December 2023, the OCC filed an application for rehearing and the PUCO granted OCC's application for rehearing for further consideration of issues raised. As a result of a Supreme Court of Ohio decision regarding procedural issues related to applications for rehearing, PUCO denied OCC’s rehearing request. In October 2024, the OCC filed its Notice of Appeal with the Ohio Supreme Court. The case is fully briefed, and oral argument is expected to be scheduled to occur during the third quarter of 2025.

In April 2024, Duke Energy Ohio filed with the PUCO a request for an Electric Security Plan (ESP). The ESP application proposed a three-year term from June 1, 2025, through May 31, 2028, and included continuation of market-based rates for generation supply through competitive procurement processes and continuation and expansion of existing rider mechanisms. Duke Energy Ohio proposed a new rider mechanism relating to electric distribution infrastructure modernization programs, which may be enabled by and partially funded through federal or state funding opportunities, as well as future battery storage projects and two electric vehicle programs. Additional proposals included new rider mechanisms related to solar for all investments for low-income and disadvantaged communities, low-income senior citizen bill assistance, and energy efficiency (EE) and demand-side management programs.

In November 2024, Duke Energy Ohio filed a stipulation that the majority of the intervenors signed as either signatory or non-opposing parties. The stipulation includes the continuation of market-based customer rates for generation supply through competitive procurement auctions and the continuation of all existing riders. It further establishes new caps for certain riders. Duke Energy Ohio also agreed to withdraw its proposals for an infrastructure modernization rider, battery storage projects and electric vehicle programs. The stipulation includes a residential EE program with provisions for low-income customers. The evidentiary hearing concluded in January 2025 and the case was fully briefed on March 14, 2025.

On April 30, 2025, Ohio Substitute House Bill 15 (HB 15) was passed and sent to the governor of Ohio. HB 15 will be effective 90 days after approval by the governor or the expiration of a 10-day review period if the governor takes no action. Duke Energy Ohio anticipates HB 15 will become law by August 10, 2025. HB 15 requires electric distribution utilities to file a base rate case every three years, commencing no later than December 31, 2029, and establishes an opportunity to apply for approval of a three-year rate plan with forward-looking test periods to mitigate regulatory lag. HB 15 eliminates ESPs and certain distribution-related riders, but permits ESPs approved as of the effective date of HB 15 to remain in place through the end of their authorized term. HB 15 also eliminates Duke Energy Ohio's Legacy Generation Rider (LGR) upon the effective date of HB 15 and prevents the PUCO from future reauthorization of similar arrangements. As a result of HB 15, any future losses related to Duke Energy Ohio's Inter-Company Power Agreement with OVEC will not be recoverable from retail customers. Additionally, regulatory assets related to OVEC at the time of HB 15 becoming effective may not be recoverable. Regulatory assets related to OVEC were $24 million and $30 million as of March 31, 2025, and December 31, 2024, respectively.

In December 2022, Duke Energy Kentucky filed a rate case with the KPSC driven by capital investments to strengthen the electricity generation and delivery systems along with adjusted depreciation rates for the East Bend and Woodsdale Combustion Turbine (CT) generation stations. Duke Energy Kentucky also requested approval for new programs and tariff updates, including a voluntary community-based renewable subscription program and two electric vehicle charging programs. The KPSC issued an order on October 12, 2023, including a $48 million increase in base revenues, an ROE of 9.75% for electric base rates and 9.65% for electric riders and an equity ratio of 52.145%. New rates went into effect October 13, 2023. Duke Energy Kentucky's request to align the depreciation rates of East Bend with a 2035 retirement date was denied and the KPSC ordered depreciation rates with a 2041 retirement date for the unit. The KPSC did approve the request to align the depreciation rates of Woodsdale CT with a 2040 retirement date and denied the voluntary community-based renewable subscription program and the two electric vehicle charging programs.

In November 2023, Duke Energy Kentucky filed for rehearing requesting certain matters be reconsidered by the KPSC and the KPSC granted in part and denied in part Duke Energy Kentucky's request for rehearing. On July 1, 2024, the KPSC issued its final order on rehearing, ruling in Duke Energy Kentucky's favor on nearly all issues. However, the KPSC ordered Duke Energy Kentucky to refund alleged over collections since the KPSC order on October 12, 2023. On July 10, 2024, the KPSC issued an order correcting the base fuel rate used to calculate new base rates in its July 1, 2024 order and its calculation of Duke Energy Kentucky's Street Lighting Rate. New rates were implemented in August 2024.

On December 14, 2023, Duke Energy Kentucky filed an appeal with the Franklin County Circuit Court on certain matters for which the KPSC denied rehearing, specifically as it relates to including decommissioning costs in depreciation rates for East Bend and Woodsdale. Duke Energy Kentucky and Appellee briefs were filed in 2024.

In December 2024, Duke Energy Kentucky filed a base rate case with the KPSC requesting an annualized increase in electric base rates of approximately $70 million and an ROE of 10.85% with an equity ratio of 52.728%. This is an overall increase of approximately 14.7%. The request for the rate increase is driven by capital investments to strengthen the electricity generation and delivery systems. New rates are anticipated to go into effect around July 2, 2025. An evidentiary hearing is scheduled to begin on May 21, 2025.

In Duke Energy Indiana’s 2019 rate case, the IURC also opened a subdocket for post-2018 coal ash related expenditures. Duke Energy Indiana filed testimony in April 2020, in the coal ash subdocket requesting recovery for the post-2018 coal ash basin closure costs for plans that have been approved by the Indiana Department of Environmental Management (IDEM) as well as continuing deferral, with carrying costs, on the balance of such coal ash basin closure costs. On November 3, 2021, the IURC issued an order allowing recovery for post-2018 coal ash basin closure costs for the plans that have been approved by IDEM, as well as continuing deferral, with carrying costs, on the balance. The OUCC and the Duke Industrial Group appealed. The Indiana Court of Appeals issued its opinion on February 21, 2023, reversing the IURC's order to the extent that it allowed Duke Energy Indiana to recover federally mandated costs incurred prior to the IURC's November 3, 2021 order. In addition, the court found that any costs incurred pre-petition to determine federally mandated compliance options were not specifically authorized by the statute and should also be disallowed.

In 2023, Duke Energy Indiana filed its proposal to remove from rates certain costs incurred prior to the IURC's November 3, 2021 order date. On September 20, 2023, the IURC approved Duke Energy Indiana's proposal to remove the costs from its rates and assessed simple interest of the refunds of 4.71%, beginning from when the costs were initially recovered from customers. Duke Energy Indiana included a request to recover the pre-order costs denied by the Indiana Court of Appeals and certain future coal ash closure costs as part of depreciation costs in the 2024 Indiana Rate Case.

In 2023, Duke Energy Indiana filed a petition under the amended version of the federal mandate statute for additional post-2018 coal ash closure costs for the remaining basins not included in the Indiana coal ash recovery case from 2020. On May 8, 2024, the IURC issued a CPCN and approved these coal ash related compliance projects as federally mandated compliance projects. In June 2024, the Citizens Action Coalition of Indiana (CAC) filed a motion to appeal the IURC order granting the coal ash CPCN proceeding and approving the coal ash related compliance projects. Briefing was completed in January 2025, and Duke Energy Indiana is awaiting an opinion from the appellate court.

In November 2021, Duke Energy Indiana filed for approval of the Transmission, Distribution, Storage Improvement Charge 2.0 investment plan for 2023-2028 (TDSIC 2.0). On June 15, 2022, the IURC approved, without modification, TDSIC 2.0, which includes approximately $2 billion in transmission and distribution investments selected to improve customer reliability, harden and improve resiliency of the grid, enable expansion of renewable and distributed energy projects and encourage economic development. In July 2022, the OUCC filed a notice of appeal to the Indiana Court of Appeals in Duke Energy Indiana’s TDSIC 2.0 proceeding. The Indiana Court of Appeals issued its opinion on March 9, 2023, affirming the IURC’s order in its entirety. The Duke Industrial Group filed a petition to transfer to the Indiana Supreme Court. On December 19, 2024, the Indiana Supreme Court affirmed the Indiana Court of Appeals decision, concluding there was substantial evidence that the IURC's conclusion was reasonable and the TDSIC 2.0 plan met the statutory requirements. On January 21, 2025, the Duke Industrial Group filed a motion for rehearing. On March 4, 2025, the Indiana Supreme Court denied the Duke Industrial Group's petition for rehearing. There can be no further appeals on TDSIC 2.0 and this matter is now fully resolved.

In April 2024, Duke Energy Indiana filed an application with the IURC for a rate increase of $492 million, representing an overall average bill increase of approximately 16.2%, which, if approved, would be added to retail customer bills in two steps, approximately 11.7% in 2025 and approximately 4.5% in 2026. Duke Energy Indiana requested an ROE of 10.5% with an equity ratio of 53%. The rate increase is driven by $1.6 billion in investments made since the last general rate case filed in 2019 in order to reliably serve customers, improve resiliency of the system, and advance environmental sustainability.

An order for the rate case was issued by the IURC on January 29, 2025, and revised February 3, 2025, which authorized an ROE of 9.75%, an equity ratio of 53% and an annual revenue increase of $296 million. Based on review of these orders, Duke Energy Indiana identified an inconsistency in the calculation of operating revenues before the effect of trackers. On February 7, 2025, Duke Energy Indiana made a compliance filing in accordance with the IURC's findings in its order and addressed the identified inconsistencies. The compliance filing also clarified the annual revenue increase was approximately $385 million. Additionally, on February 18, 2025, one industrial customer submitted a filing requesting the IURC to clarify its revenue allocation in these proceedings, which was denied by the Commission on April 16, 2025. On February 25, 2025, the IURC approved Duke Energy Indiana’s compliance filing and new rates were implemented February 27, 2025. The industrial customer filed a notice of appeal on February 28, 2025, regarding cost of service allocation. On April 9, 2025, the IURC issued an order correcting its January 29, 2025 order to apply a rate migration adjustment to industrial customers. An industrial customer appealed the IURC order to the Indiana Court of Appeals, but this appeal has been stayed.

On February 13, 2025, Duke Energy Indiana filed for a CPCN seeking approval to construct two 1x1 CC natural gas-fired units with a combined winter rating of 1,476 MW. The Cayuga CC Project is proposed to be constructed on the same site as the retiring Cayuga coal-fired steam units with a winter rating of 1,005 MW. The Cayuga CC Project will result in an incremental 471 MW for the Duke Energy Indiana system and will allow Duke Energy Indiana to avoid expected maintenance and environmental compliance costs needed for the coal units to continue operating. The estimated cost of the Cayuga CC project is approximately $3 billion, plus AFUDC and project reserves. Duke Energy Indiana has proposed recovery of certain facility costs during construction, including AFUDC, through construction work in progress ratemaking via a proposed generation cost adjustment tracker mechanism. The estimated average retail rate impact during construction and initial in-service periods from April 2026 through May 2031 is approximately 5.4%. Duke Energy Indiana expects CC 1 to be placed in service in 2029 and CC 2 to be placed in service in 2030. A final air permit was issued by IDEM on March 5, 2025. An evidentiary hearing related to the CPCN is scheduled to begin on June 19, 2025. An order is expected by October 2025.