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TVA’s Analysis of the Power Supply Plan Reliability

Report Information

Date Issued
Report Number
2023-17465
Report Type
Inspection / Evaluation
Description
The Tennessee Valley Authority’s (TVA) Power Supply Plans (PSPs) combine optimized capacity and generation plans that balance load and power supply and provide detailed dispatch and generation forecasts used in resource decisions, budgeting, and analysis. PSPs incorporate key planning assumptions, including load and commodity forecasts, fleet characteristics, and other inputs, applying least cost planning methodology. TVA’s 2025 Draft Integrated Resource Plan identified the TVA region is experiencing increasing demand for electricity driven by population, employment, and industrial growth, weather trends, and increasing electric vehicle usage. Due to the importance of effective power supply planning to meet future load and energy demand requirements, we performed an evaluation of TVA’s analysis of the reliability of the PSP. The objective of our evaluation was to evaluate TVA’s process for analyzing the reliability of the PSP and taking corrective actions as necessary. We determined TVA took steps to analyze the reliability of some elements of the PSP and took corrective actions as necessary. While TVA does not have a Standard Program and Process defining analysis of the reliability of the PSP, we found that TVA utilized several procedures and practices to provide governance of its power supply planning process. Additionally, we identified examples of corrective actions TVA had taken to improve the reliability of some aspects of the PSP. We also found some elements of the PSP process that could impact its reliability. Specifically, we identified (1) significant variance in near-term planned system changes, (2) misalignment of cost assumptions in the modeling and approvals process, (3) some PSP input controls not working as designed, and (4) several Standard Programs and Processes past their review cadence.
Joint Report
No
Agency Wide
Yes (agency-wide)
Questioned Costs
$0
Funds for Better Use
$0
View report on Oversight.gov

Recommendations

We recommend the Vice President, Enterprise Planning, take steps to improve consistency in the capacity plan.

We recommend the Vice President, Enterprise Planning, evaluate the solar cost assumptions in the capacity planning model and take actions as necessary.

We recommend the Vice President, Enterprise Planning, consider aligning the Power Supply Plan Input Schedule with the Power Supply Plan Inputs listed in procedures.

We recommend the Vice President, Enterprise Planning, ensure Power Supply Plan inputs are approved and submitted by designated input providers for inclusion in the Power Supply Plan.

We recommend the Vice President, Enterprise Planning, review, update, and approve the Standard Programs and Processes in the Power Supply Plan process.