Power Purchase Obligations. TVA has contracted with various independent power producers and LPCs for additional capacity to be made available to TVA. Several of these agreements have contractual minimum payments and are accounted for as either finance or operating leases. In total, these agreements provide 5,938 megawatts ("MW") of summer net capability. The remaining terms of the agreements range up to 23 years. Additionally, TVA has contracted with regional transmission organizations to reserve 3,750 MW of transmission service to support purchases from the market and certain PPAs. The remaining terms of these agreements range up to six years. TVA has recorded $696 million, $519 million, and $355 million of expense under these power purchase and transmission service agreements during 2025, 2024, and 2023, respectively.

Nuclear Insurance. Section 170 of the Atomic Energy Act, commonly known as the Price-Anderson Act, provides a layered framework of financial protection to compensate for liability claims of members of the public for personal injury and property damages arising from a nuclear incident in the U.S. This financial protection consists of two layers of coverage. The primary level is private insurance underwritten by American Nuclear Insurers and provides public liability insurance coverage of $500 million for each nuclear power plant licensed to operate. If this amount is not sufficient to cover claims arising from a nuclear incident, the second level, Secondary Financial Protection, applies. Within the Secondary Financial Protection level, the licensee of each nuclear reactor has a contingent obligation to pay a retrospective premium, equal to its proportionate share of the loss in excess of the primary level, regardless of proximity to the incident of fault, up to a maximum of approximately $166 million per reactor per incident. With TVA's seven reactors, the maximum total contingent obligation per incident is $1.2 billion. This retrospective premium is payable at a maximum rate currently set at approximately $25 million per year per nuclear incident per reactor. Currently, 95 reactors are participating in the Secondary Financial Protection program.

Federal law requires that each NRC power reactor licensee obtain property insurance from private sources to cover the cost of stabilizing and decontaminating a reactor and its station site after an accident. TVA carries property, decommissioning liability, and decontamination liability insurance from Nuclear Electric Insurance Limited ("NEIL") and European Mutual Association for Nuclear Insurance. The limits available for a loss are up to $2.1 billion for two of TVA's nuclear sites and up to $2.8 billion for the remaining site. Some of this insurance may require the payment of retrospective premiums up to a maximum of approximately $122 million.

TVA purchases accidental outage (business interruption) insurance for TVA's nuclear sites from NEIL. In the event that an accident covered by this policy takes a nuclear unit offline or keeps a nuclear unit offline, NEIL will pay TVA, after a waiting period, an indemnity (a set dollar amount per week) with a maximum indemnity of $490 million per unit. This insurance policy may require the payment of retrospective premiums up to a maximum of approximately $50 million, but only to the extent the retrospective premium is deemed necessary by the NEIL Board of Directors to pay losses unable to be covered by NEIL's surplus.

Nuclear Decommissioning. Provision for decommissioning costs of nuclear generating units is based on options authorized by the NRC procedures to dismantle and decontaminate the facilities to meet the NRC criteria for license termination. At September 30, 2025, $4.0 billion, representing the discounted value of future estimated nuclear decommissioning costs, was included in nuclear AROs. The actual decommissioning costs may vary from the derived estimates because of, among other things, changes in current assumptions, such as the assumed dates of decommissioning, changes in regulatory requirements, changes in technology, and changes in the cost of labor, materials, and equipment. Utilities that own and operate nuclear plants are required to use different procedures in calculating nuclear decommissioning costs under GAAP than those that are used in calculating nuclear decommissioning costs when reporting to the NRC. The two sets of procedures produce different estimates for the costs of decommissioning primarily because of differences in the underlying assumptions. TVA bases its nuclear decommissioning estimates on site-specific cost studies. The most recent study was approved and implemented in September 2022. Site-specific cost studies are updated for each of TVA's nuclear units at least every five years.

TVA maintains an NDT to provide funding for the ultimate decommissioning of its nuclear power plants. See Note 17 — Fair Value Measurements — Investment Funds. TVA monitors the value of its NDT and believes that, over the long term and before cessation of nuclear plant operations and commencement of decommissioning activities, adequate funds from investments and additional contributions, if necessary, will be available to support decommissioning. TVA's operating nuclear power units are licensed through various dates between 2033 - 2055, depending on the unit. It may be possible to extend the operating life of some of the units with approval from the NRC. See Note 11 — Regulatory Assets and Liabilities — Nuclear Decommissioning Costs and Note 14 — Asset Retirement Obligations.

Non-Nuclear Decommissioning. At September 30, 2025, $6.4 billion, representing the discounted value of future estimated non-nuclear decommissioning costs, was included in non-nuclear AROs. This decommissioning cost estimate involves estimating the amount and timing of future expenditures and making judgments concerning whether or not such costs are considered a legal obligation. Estimating the amount and timing of future expenditures includes, among other things, making projections of the timing and duration of the asset retirement process and how costs will escalate with inflation. The actual decommissioning costs may vary from the derived estimates because of changes in current assumptions, such as the assumed dates of decommissioning, changes in regulatory requirements, changes in technology, and changes in the cost of labor, materials, and equipment. TVA updates its underlying assumptions for non-nuclear decommissioning AROs at least every five years. However, material changes in underlying assumptions that impact the amount and timing of undiscounted cash flows are continuously monitored and incorporated into ARO balances in the period identified.

TVA maintains an ART to help fund the ultimate decommissioning of its non-nuclear power assets. See Note 17 — Fair Value Measurements — Investment Funds. Estimates involved in determining if additional funding will be made to the ART include inflation rate, rate of return projections on the fund investments, and the planned use of other sources to fund decommissioning costs. See Note 11 — Regulatory Assets and Liabilities — Non-Nuclear Decommissioning Costs and Note 14 — Asset Retirement Obligations.

Environmental Matters. TVA's generation activities, like those across the utility industry and in other industrial sectors, are subject to federal, state, and local environmental laws and regulations. Major areas of regulation affecting TVA's activities include air quality control, greenhouse gas ("GHG") emissions, water quality control, and management and disposal of solid and hazardous wastes. Regulations in these major areas continue to evolve.

TVA has incurred, and expects to continue to incur, substantial capital and operating and maintenance costs to comply with evolving environmental requirements primarily associated with, but not limited to, the operation of TVA's coal-fired and natural gas-fired generating units in general and emissions of pollutants from those units. Failure to comply with environmental and safety requirements can result in enforcement actions and litigation, which can lead to the imposition of significant civil liability, including fines and penalties, criminal sanctions, and/or temporary or permanent closure of non-compliant facilities. Historical non-compliance can also lead to difficulty in renewing existing permits, as well as difficulty in obtaining permits to bring new generation facilities online. Other obstacles to renewal or permitting of new facilities include a proliferation of non-government organizations seeking to use litigation tools to drive up costs associated with, and delay or prevent permitting of, new fossil fuel facilities and related infrastructure in favor of renewable energy projects.

Compliance with the 2015 CCR Rule required implementation of a groundwater monitoring program, additional engineering, evaluation of authorized closure methods, coordination with certain state authorities, and ongoing analysis at each TVA CCR unit. As further analyses are performed, including evaluation of monitoring results, there is the potential for additional costs for investigation and/or remediation. In addition, on May 8, 2024, EPA published its Legacy CCR Rule, which expands the scope of the existing regulatory requirements of the 2015 CCR Rule to include two additional classes of CCR units: Legacy SIs and CCRMUs. As a result of the enactment of the final rule, during 2024, TVA recorded additional estimated AROs and recorded a corresponding regulatory asset due to AROs being associated with closed sites and asset retirement costs having been fully depreciated. However, the amounts recorded are subject to various uncertainties, and actual amounts may differ materially based upon a number of factors, including, but not limited to, the outcome of legal challenges to the Legacy CCR Rule, ongoing evaluations of the number and scope of newly regulated units, determinations on final closure requirements and performance standards, and possible changes to the Legacy CCR Rule by EPA. See Note 14 — Asset Retirement Obligations.

In May 2024, EPA also published (1) a final rule that establishes more stringent technology-based effluent limitations for four wastewater streams from coal-fired plants, (2) a rule that strengthens and updates the Mercury and Air Toxics Standards for electric generating units to reflect recent developments in control technologies, and (3) a rule that establishes GHG emission guidelines for existing coal-fired plants and GHG performance standards for new natural gas-fired power plants. These rules are all currently being reconsidered by EPA and are also all subject to legal challenges. If these rules move forward as written and the challenges are not successful, TVA would incur substantial costs to comply with the rules.

On March 12, 2025, the EPA Administrator announced that EPA will reconsider 31 rules, including (1) regulations on power plants, (2) Mercury and Air Toxics Standards, (3) steam electric effluent limitation guidelines, (4) National Ambient Air Quality Standards for particulate matter, (5) regulations regarding regional haze, (6) the Good Neighbor Plan, and (7) CCR regulations. TVA cannot predict the outcome of such reevaluations or their impact on TVA's financial results or operations.

Liability for releases, natural resource damages, and required cleanup of hazardous substances is primarily regulated by the federal Comprehensive Environmental Response, Compensation, and Liability Act ("CERCLA"), the Resource Conservation and Recovery Act ("RCRA"), and other federal and parallel state statutes. In a manner similar to many other governmental entities, industries, and power systems, TVA has generated or used hazardous substances over the years. TVA operations at some facilities have resulted in releases of contaminants that TVA has addressed or is addressing consistent with state and federal requirements. At September 30, 2025 and 2024, TVA's estimated liability for required cleanup and similar environmental work for those sites for which sufficient information is available to develop a cost estimate was $8 million and $15 million, respectively, on a non-discounted basis, and was included in Accounts payable and accrued liabilities and Other long-term liabilities on the Consolidated Balance Sheets. Additionally, the potential inclusion of new hazardous substances under CERCLA and RCRA jurisdiction could significantly affect TVA's future liability for remediating historical releases.

In August 2015, the Tennessee Department of Environment and Conservation ("TDEC") issued an order that includes an iterative process through which TVA and TDEC will identify and evaluate any CCR contamination risks and, if necessary, respond to such risks. TVA is also following a similar process pursuant to a consent order. At September 30, 2025 and 2024, TVA's estimated liability for costs associated with environmental remediation activities for the sites covered by these orders for which sufficient information is available to develop a cost estimate was approximately $319 million and $215 million, respectively, on a non-discounted basis and was included in Accounts payable and accrued liabilities and Other long-term liabilities on the Consolidated Balance Sheets. The current estimated time frame for work related to these remediation activities for which TVA has a cost estimate is through 2044.

General. At September 30, 2025, TVA had accrued $11 million of probable losses with respect to Legal Proceedings. Of the accrued amount, $9 million is included in Other long-term liabilities and $2 million is included in Accounts payable and accrued liabilities. No assurance can be given that TVA will not be subject to significant additional claims and liabilities. If actual liabilities significantly exceed the estimates made, TVA's results of operations, liquidity, and financial condition could be materially adversely affected.

Environmental Agreements. On April 14, 2011, TVA entered into two substantively similar agreements, one with the EPA and the other with Alabama, Kentucky, North Carolina, Tennessee, and three environmental advocacy groups (collectively, the "Environmental Agreements"). To resolve alleged New Source Review claims, TVA committed under the Environmental Agreements to, among other things, take now-completed actions regarding coal units and invest $290 million in certain TVA environmental projects. Of this amount, TVA had spent approximately $285 million as of September 30, 2025. Additionally, TVA holds restricted cash in an interest earning trust to fund the remaining project commitments. Any interest earned through the trust must also be spent on agreed upon environmental projects. The total remaining committed costs, including interest earned through the trust, were approximately $7 million as of September 30, 2025.

The liabilities related to the Environmental Agreements are included in Accounts payable and accrued liabilities and Other long-term liabilities on the September 30, 2025, Consolidated Balance Sheets. In conjunction with the approval of the Environmental Agreements, the TVA Board determined that it was appropriate to record TVA's obligations under the Environmental Agreements as regulatory assets, and they are included as such on the September 30, 2025, Consolidated Balance Sheets and will be recovered in rates in future periods.

Case Involving Johnsonville Aeroderivative Combustion Turbine Project. On December 22, 2022, the Southern Environmental Law Center filed a lawsuit in the U.S. District Court for the Middle District of Tennessee on behalf of the Sierra Club, alleging that TVA violated the National Environmental Policy Act ("NEPA") in deciding to build a new aeroderivative combustion turbine project at its Johnsonville facility. Both parties moved for summary judgment, and on September 30, 2024, the court granted TVA's motion for summary judgment and dismissed the lawsuit. The Sierra Club did not file an appeal within 60 days from the date of the decision, so this litigation has now ended.

Case Involving Cumberland Combined Cycle Plant. On June 14, 2023, Appalachian Voices, the Center for Biological Diversity, and the Sierra Club filed a lawsuit in the United States District Court for the Middle District of Tennessee alleging that TVA violated NEPA in deciding to build a 1,450 MW combined cycle plant at its Cumberland facility. The plaintiffs request the court, among other things, to enter a declaratory judgment that the Cumberland Environmental Impact Statement ("EIS") violated NEPA and TVA's decision to issue the Cumberland Record of Decision was arbitrary, capricious, and/or not in accordance with law; enter a declaratory judgment that TVA’s failure to supplement the Cumberland EIS violated NEPA and was arbitrary, capricious, and/or not in accordance with law; vacate the Cumberland EIS and the Cumberland Record of Decision; order TVA to prepare a revised draft EIS or supplemental EIS subject to public comment that corrects the NEPA violations identified by the plaintiffs; and enjoin further construction and operation of the Cumberland combined cycle plant until TVA has complied with NEPA. TVA filed an amended answer on September 14, 2023. On February 13, 2024, the plaintiffs filed a motion to complete the administrative record that TVA submitted in support of the EIS for this project, alleging that the administrative record submitted by TVA is incomplete. The magistrate judge issued an order granting in part and denying in part the plaintiffs' motion to complete the administrative record. TVA subsequently filed a motion challenging the magistrate judge's ruling, and TVA's motion is pending before the court. In light of the outstanding issues related to the administrative record, the court suspended the parties' summary judgment deadlines. TVA cannot predict the outcome of this litigation.

Challenge to Certificate for Cumberland Pipeline. On April 29, 2024, the Southern Environmental Law Center, on behalf of the Sierra Club and Appalachian Voices, filed a petition with the United States Court of Appeals for the District of Columbia Circuit ("D.C. Circuit") challenging the issuance by the Federal Energy Regulatory Commission ("FERC") of a certificate of public convenience for the pipeline that will need to be constructed in order for TVA to operate the Cumberland Combined Cycle Plant (the “Cumberland Pipeline”). The petitioners allege that they and their members have been and will be aggrieved by the approval, construction, and operation of the Cumberland Pipeline and are asking the D.C. Circuit to review and set aside FERC’s order approving the pipeline. The D.C. Circuit heard oral arguments on the merits on March 4, 2025, and on September 30, 2025, the D.C. Circuit issued an opinion upholding FERC's decision to issue the certificate of public convenience for the pipeline.

Case Involving Kingston Gas-Fired Plant. On October 10, 2024, Appalachian Voices, the Center for Biological Diversity, and the Sierra Club filed a lawsuit in the United States District Court for the Eastern District of Tennessee alleging that TVA violated NEPA and TVA’s least-cost planning obligations in deciding to build a gas plant at its Kingston facility. The plaintiffs requested that the court, among other things, enter a declaratory judgment that the Kingston EIS violated NEPA and that TVA's decision to issue the Kingston Record of Decision was arbitrary, capricious, and/or not in accordance with law; enter a declaratory judgment that TVA’s least-cost-planning analysis was arbitrary, capricious, and/or not in accordance with law; vacate the Kingston Final EIS and the Kingston Record of Decision; order TVA to prepare a revised draft EIS or supplemental EIS that

complies with NEPA and least-cost-planning requirements; and enjoin further construction and operation of the Kingston Gas Plant until TVA has complied with NEPA, least-cost-planning requirements, and the Administrative Procedure Act. TVA filed its answer on December 16, 2024, and filed the administrative record on May 2, 2025. The plaintiffs filed a motion to complete the administrative record on June 30, 2025, and TVA filed its response on July 30, 2025. The plaintiffs filed a reply brief on August 8, 2025. TVA cannot predict the outcome of this litigation.

Challenge to Kingston Construction Permit. On December 16, 2024, the Southern Environmental Law Center filed an appeal on behalf of Appalachian Voices challenging the construction permit that the Technical Secretary acting on behalf of the Tennessee Air Pollution Control Board issued to TVA on November 15, 2024, for the construction of natural gas generation at Kingston. Appalachian Voices alleges that TDEC unlawfully issued a construction permit that would allow TVA to construct the plant without meeting the requirements set forth in the Tennessee Air Quality Act's and Federal Clean Air Act’s Prevention of Significant Deterioration program. Among other things, Appalachian Voices is requesting that the Tennessee Air Pollution Control Board stay the effectiveness of the permit and order TDEC to revoke the permit. On January 7, 2025, TVA filed a petition to intervene in the administrative proceeding, which was granted on January 15, 2025. The parties filed competing motions for summary judgment on March 14, 2025, and oral argument on these motions was held on June 24, 2025. On August 20, 2025, the administrative law judge issued an order upholding the construction permit and denying Appalachian Voices' petition challenging the permit. Appalachian Voices did not appeal the initial order to the Tennessee Air Pollution Control Board by the deadline of September 19, 2025, so the order became final. Appalachian Voices can seek judicial review of the final order by filing a petition within 60 days of the order becoming final.