Evaluation of Two Arizona-Based 2020 Integrated Resource Plans


Synapse supported Sierra Club in its engagement in Arizona Public Service (APS) and Tucson Electric Power’s (TEP) Integrated Resource Planning (IRP) process. Over the course of the last two years, Synapse attended and participated in many IRP workshops and stakeholder sessions on behalf of the Sierra Club. Synapse also prepared several presentations to the Commission and utilities with recommendations for improving APS and TEP's IRPs. Finally, Synapse assisted in the development of several rounds of comments on both APS and TEP’s IRPs. These comments identified areas in which TEP and APS respectively failed to advance the goals of protecting ratepayers, providing transparency, and operating a well-planned and efficient electricity system.

Synapse and Sierra Club recommendations to APS focused on the following topics:

  • APS should develop a more reasonable load forecast that incorporates COVID impacts and corrects the historical pattern of over forecasting load
  • APS should better justify its modeling assumptions and decisions that continue to systematically favor new gas resources and disadvantage renewables, and the Company should not be able to add any new gas resources in the near term based on its current modeling.
  • APS should conduct a study that properly models the economics of retiring the Four Corners Coal plant early and paying out the remaining coal contract relative to retiring it early and replacing it with clean energy resources.
  • APS should properly reflect the costs and risks associated with future environmental regulations, including the coal combustion residuals and effluent limitation guideline rules, and the risk of water shortages.

Synapse and Sierra Club recommendations to TEP focus on the following topics:

  • TEP should improve its modeling tools and employ optimized capacity expansion modeling.
  • TEP should demonstrate how it will reduce its reliance on fossil resources in light of the substantial quantity of new gas resources it produced just prior to the IRP.
  • TEP should utilize gas prices that are higher and more aligned with those forecasted by the US Energy Information Administration (EIA) Annual Energy Outlook (AEO).
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