Tucson Electric Power and Arizona Public Service IRPs


Sierra Club retained Synapse to review the input assumptions and modeling methodologies underlying the 2017 Integrated Resource Plans (IRP) filed by Arizona Public Service Company (APS) and Tucson Electric Power Company (TEP). In comments submitted on behalf of Sierra Club, Synapse presented evidence that APS's plan to build thousands of megawatts of new natural gas-fired capacity was based on a a series of analytical errors and flawed assumptions including an unrealistically high load forecast, under-statement of available cost-effective energy efficiency, inflated renewable costs, and deflated natural gas prices. Synapse recommended that APS hold off on procuring new gas capacity until it had produced an analysis containing a more reasonable set of assumptions. In comments on TEP's IRP, Synapse recommended that TEP revise its modeling to capture a wider range of scenarios and potential portfolios, and more rigorously assess the economic status of its coal units. Citing Synapse's comments, the Arizona Corporation Commission declined to acknowledge the IRPs submitted by APS and TEP, and imposed a series of requirements to ensure that future IRPs incorporate reasonable load-growth scenarios and evaluate a reasonable range of portfolios and sensitivities.

Project completed May 2018