AriSEIA Responds to APS' Supplemental Testimony on Cholla

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After Arizona Public Service (APS) announced plans to convert the Cholla Power Plant from coal to natural gas just weeks after testifying that it did not have a "definitive plan" and that a stakeholder process was "too early," AriSEIA asked the Administrative Law Judge to recall APS witness Jacob Tetlow for additional testimony. Instead of recalling the witness, the Judge directed APS to provide written responses to supplemental questions. APS has now filed those responses, and AriSEIA has responded.

Our response explains why the written testimony raises more questions than it answers. Among other things, APS now claims the project had been incorporated into its resource planning process, yet stakeholders were never provided the purported IRP base case on the date APS identifies. APS also admits the proposed Cholla conversion was not part of the 2025 All-Source Request for Proposals (ASRFP) and that its analysis did not include production cost modeling, fuel costs, variable operating costs, or energy market impacts.

The issue is not whether the Cholla conversion should ultimately be approved. It is whether stakeholders and Commissioners received complete and accurate information during the rate case and whether APS' supplemental testimony supports its claim that everyone was already on notice of the project.

AriSEIA's response asks the Administrative Law Judge to carefully consider these deficiencies when evaluating APS' late-filed testimony. Transparency and meaningful stakeholder participation are essential to sound utility planning, particularly when major generation decisions are announced after testimony has concluded.