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Plant Closures (Text Block) | 12 Months Ended
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Sep. 30, 2023
Property, Plant and Equipment [Abstract] |
Plant Closures | 7. Plant Closures Background TVA must continuously evaluate all generating assets to ensure an optimal energy portfolio that provides safe, clean, and reliable power while maintaining flexibility and fiscal responsibility to the people of the Tennessee Valley. Based on results of assessments presented to the TVA Board in 2019, the retirement of Bull Run Fossil Plant ("Bull Run") by December 2023 was approved, and as of September 30, 2023, the facility was retired. In addition, TVA is evaluating the impact of retiring the balance of the coal-fired fleet by 2035, and that evaluation includes environmental reviews, public input, and TVA Board approval. Due to these evaluations, certain planning assumptions were updated, and their financial impacts are discussed below. In January 2023, TVA issued its Record of Decision to retire the two coal-fired units at Cumberland Fossil Plant ("Cumberland") by the end of CY 2026 and CY 2028. 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. As a result of TVA's decision to accelerate the retirement of Bull Run, TVA has recognized a cumulative $659 million of accelerated depreciation since the second quarter of 2019. Of this amount, $177 million, $140 million, and $136 million were recognized for the years ended September 30, 2023, 2022, and 2021, respectively. 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. TVA estimates it has recognized a cumulative $48 million of additional depreciation since January 2023, related to this decision. TVA also recognized $14 million, $22 million, and $4 million in Operating and maintenance expense related to additional inventory reserves and project write-offs for the coal-fired fleet, including Bull Run

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