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Plant Closures (Text Block) | 12 Months Ended
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Sep. 30, 2025
Property, Plant and Equipment [Abstract] |
Plant Closures | . Plant Closures Background TVA must continuously evaluate all generating assets to ensure an optimal energy portfolio that provides safe and reliable power while maintaining flexibility and fiscal responsibility to the people of the Tennessee Valley. In January 2023, TVA issued its Record of Decision to retire two coal-fired units at Cumberland Fossil Plant ("Cumberland") by the end of CY 2026 and CY 2028. In April 2024, TVA issued its Record of Decision to retire the nine coal-fired units at Kingston Fossil Plant ("Kingston") by CY 2027. TVA is evaluating the impact of retiring the balance of the coal-fired fleet by 2035, and that evaluation includes environmental reviews and TVA Board approval. TVA is also reviewing how recent executive orders, the evolving regulatory environment, and overall system performance are impacting the operation of its coal-fired fleet. An evaluation of the continued operation of coal-fired units is being conducted and will consider material condition, plant performance, system flexibility needs, environmental requirements, grid support, and other factors. Financial Impact TVA's policy is to adjust depreciation rates to reflect the most current assumptions, ensuring units will be fully depreciated by the applicable retirement dates. TVA's decision to retire the two units at Cumberland is estimated to result in approximately $16 million of additional depreciation quarterly, which does not include any potential impact from additions or retirements to net completed plant. The cumulative impact approximates $176 million of additional depreciation since January 2023, related to this decision. In addition, TVA's decision to retire the nine units at Kingston is estimated to result in approximately $9 million of additional depreciation quarterly, which does not include any potential impact from additions or retirements to net completed plant. The cumulative impact approximates $54 million of additional depreciation since April 2024 related to this decision. TVA also recognized $15 million, $15 million, and $14 million in Operating and maintenance expense related to additional inventory reserves for the coal-fired fleet, including Kingston, Cumberland, and Bull Run Fossil Plant, for the years ended September 30, 2025, 2024, and 2023, respectively.

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