The Arizona Solar Energy Industries Association (AriSEIA) filed its Responsive Brief in Arizona Public Service Company's (APS) pending rate case, urging the Arizona Corporation Commission to eliminate the Grid Access Charge (GAC) and Legacy Solar Rate Increase (LSRI). AriSEIA argues that APS still has not identified costs uniquely caused by residential solar customers that would justify imposing additional charges on them. APS's own witness acknowledged that the Company did not attempt to identify specific costs attributable to residential distributed generation customers, while Commission Staff described the GAC as a mechanism intended to recover lost fixed-cost revenues. AriSEIA argues that lost revenue is not a cost caused by solar customers and cannot provide the cost-causation basis necessary to support a solar-specific charge. AriSEIA therefore asks the Commission to resolve the issue in this rate case and eliminate both charges rather than defer the question to another proceeding.

AriSEIA also continues to oppose proposals that would undermine customer investment in distributed energy resources. The brief asks the Commission to reject Kroger's proposed changes to APS's E-32 M and E-32 L commercial rates, which would shift additional revenue recovery from volumetric energy charges to demand charges. AriSEIA argues that such a change would reduce customers' ability to lower their bills through energy efficiency, solar, and storage while working against distributed energy programs the Commission is considering in the same case. AriSEIA also urges the Commission to retain and redesign the E-32 L Storage Pilot rather than eliminate it simply because it has attracted no participants. Zero participation demonstrates that the existing tariff has not worked, not that a properly designed commercial storage tariff cannot work.
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Finally, AriSEIA asks the Commission to improve APS's virtual power plant programs by expanding Storage Rewards to non-residential customers and allowing third-party-owned systems to participate. AriSEIA argues that APS's delay in launching the program should not become a reason to postpone improvements that could expand participation and increase the value distributed batteries provide to the grid. The brief also opposes the Arizona Free Enterprise Club's proposed disallowance related to the Agave Battery Energy Storage System, noting that Agave was selected through a competitive all-source request for proposals overseen by an independent monitor and that no evidence identified an actual competing project capable of meeting similar needs at a lower cost. Together, AriSEIA's recommendations seek a rate design that fairly reflects the costs customers actually impose on the APS system while expanding opportunities for solar, storage, and other distributed energy resources.

AriSEIA filed its Initial Brief in Arizona Public Service’s current rate case, urging the Arizona Corporation Commission to eliminate the Grid Access Charge and Legacy Solar Rate Increase imposed on residential solar customers. AriSEIA argues that APS has again failed to demonstrate that customers with rooftop solar impose unique costs on the electric system that justify solar-specific charges. APS’s own cost-of-service witness acknowledged that the Company did not identify specific costs attributable to solar customers, while AriSEIA’s analysis shows that correcting flaws in APS’s methodology eliminates the alleged cost shift. Eliminating both charges would have an estimated impact of only $0.34 per month on other residential customers.
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The brief also asks the Commission to strengthen opportunities for customers to participate in distributed energy resources. AriSEIA recommends expanding APS’s virtual power plant program to commercial and industrial customers, allowing broader participation by third-party-owned systems, and improving program marketing and enrollment. AriSEIA also urges the Commission to retain and improve the E-32L Storage Pilot rather than eliminate it, and supports Microsoft’s Bring Your Own Power proposal, including recognition that aggregated distributed energy resources and virtual power plants can participate.
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On broader rate case issues, AriSEIA opposes APS’s proposed Formula Rate Adjustment Mechanism and requested 10.7% return on equity, arguing that the proposals would reduce regulatory oversight and unnecessarily increase costs for customers. AriSEIA also opposes Kroger’s proposed commercial rate design changes, which would reduce the economic value of on-site solar, while supporting recovery of APS’s Agave Battery Energy Storage System. The brief asks the Commission to adopt a rate structure that protects customers, supports clean energy investment, and expands the ability of distributed resources to provide value to APS’s system.

The Arizona Solar Energy Industries Association (AriSEIA), Vote Solar, and Solar United Neighbors have filed a joint letter urging the Arizona Corporation Commission to pause or reduce Arizona Public Service's proposed reduction to the Resource Comparison Proxy (RCP), the export rate paid to new rooftop solar customers. While Commission rules allow the RCP to decline over time, they also provide that it may not be reduced by more than 10% annually. The organizations argue that the Commission has the discretion to slow that reduction in light of today's economic and grid reliability challenges.

The filing highlights that rooftop solar installations in APS territory have fallen sharply, dropping 12% in 2025 and another 47% so far in 2026 compared to the same point last year. At the same time, APS and Tucson Electric Power are seeking higher electric rates, and APS is asking to expand its Grid Access Charge on solar customers. Together, these policies make it more difficult for Arizona families and businesses to invest in rooftop solar, even as electricity prices continue to rise.
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The letter also emphasizes the growing importance of distributed energy resources as Arizona experiences record electricity demand. Rooftop solar and battery storage help reduce peak demand, support virtual power plant programs, and lessen the need for costly new generation. With nearly 365 solar companies employing almost 10,000 Arizonans, AriSEIA and its partners argue that reducing the pace of the RCP step down would help preserve consumer choice, strengthen grid reliability, and support one of Arizona's most important clean energy industries. 

AriSEIA has joined the Arizona Attorney General, Vote Solar, and other appellants in asking the Arizona Court of Appeals to deny motions for reconsideration filed by APS and the Arizona Corporation Commission and preserve the Court's decision eliminating the APS Grid Access Charge. The joint filing argues that APS and the Commission have failed to identify any legal or factual error in the Court's opinion and instead seek to reargue issues the Court has already considered and rejected.
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The response defends the Court's conclusion that the Commission's rehearing did not cure the original due process violation. It explains that the rehearing improperly limited parties' ability to challenge the site-load Cost of Service Study, the primary evidence supporting the Grid Access Charge, while also improperly shifting the burden of proof from APS to the parties challenging the charge. According to the filing, those defects prevented the rehearing from providing the fair process required under Arizona law.
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The joint filing asks the Court to deny the motions for reconsideration, make one technical clarification to its opinion, and leave intact its decision vacating the Grid Access Charge. AriSEIA remains committed to defending fair regulatory processes and ensuring that new utility charges are adopted only after customers and stakeholders receive the full due process guaranteed by law.

Today, AriSEIA filed a motion asking the Arizona Corporation Commission to take judicial notice of new public statements made by APS CEO Ted Geisler during Pinnacle West's second quarter earnings call.

Why does this matter?

On May 26, APS Chief Operating Officer Jacob Tetlow testified under oath that APS did not have "a definitive plan" for the future of the Cholla Power Plant, was still "evaluating different alternatives," and that "the stakeholder process" was "too early."

APS later defended that testimony through supplemental testimony and legal briefing, arguing that its evaluation remained ongoing and that no final plan existed before the APS Board approved the project on June 24.

But during today's earnings call, when investors asked why APS delayed filing its 2026 Integrated Resource Plan ("IRP"), CEO Ted Geisler gave a very different explanation. Rather than citing the absence of Board approval, an ongoing evaluation, or uncertainty regarding the Company's plans, he explained that the likelihood of being able to convert Cholla was one of the reasons APS sought the extension so the conversion could be reflected in the IRP.

That statement is significant because APS requested the IRP extension on May 22, four days before Mr. Tetlow testified.
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AriSEIA's motion does not ask the Commission to reopen the evidentiary hearing or decide the merits of the Cholla conversion. Instead, it asks the Administrative Law Judge to take judicial notice of APS's subsequent public admissions and consider them when evaluating the weight and credibility of APS's evidence.

The integrity of the regulatory process depends on parties providing complete and accurate information to the Commission. When subsequent public statements appear difficult to reconcile with sworn testimony and litigation positions, the Commission should consider those statements in evaluating the evidentiary record.

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.

Arizona deserves a transparent resource planning process, especially when major generation investments could shape the state's energy mix for decades.

Just weeks after APS testified in its rate case that it did not have a definitive plan for the future of the Cholla Power Plant, the utility announced it plans to convert the facility to natural gas.

Today, AriSEIA filed supplemental questions seeking answers about when that decision was made, what alternatives were considered, and whether renewable energy and energy storage were fully evaluated alongside the proposed gas conversion. The questions also seek information about the project's costs, supporting analyses, and how the decision relates to APS' ongoing Integrated Resource Plan.
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As Arizona continues to experience rapid load growth, it is critical that utilities evaluate all available resources on a level playing field. Customers and stakeholders deserve confidence that major investment decisions are based on transparent analysis, sound economics, and a fair comparison of all available energy options.

AriSEIA has joined a motion asking the Administrative Law Judge to reconsider the admission of a report that claims solar energy is expensive and unreliable, arguing that the document lacks a disclosed methodology, was not authored by the sponsoring witness, and directly conflicts with substantial evidence already in the record.

The report, offered by the Arizona Free Enterprise Club, is a policy brief published by the Heartland Institute. Although the witness who sponsored the exhibit cited it in his testimony, he acknowledged during cross-examination that he did not write the report, did not develop its scoring system, and could not explain the methodology used to reach its conclusions.

The publication presents itself as an "objective scorecard" comparing different electric generation technologies. It assigns numerical scores to resources such as solar, wind, coal, natural gas, and nuclear, concluding that solar is among the least affordable and least reliable generation resources. However, the report contains no methodology explaining how those scores were calculated, how competing factors were weighted, or how the numerical rankings were derived.

AriSEIA's filing argues that unsupported conclusions should not be admitted for the truth of the matters asserted simply because they appear in a published report. Instead, parties should be required to demonstrate the analytical basis for factual claims that are central to issues being litigated before the Arizona Corporation Commission.

The filing also notes that the report's conclusions are inconsistent with other evidence already admitted into the case, including APS's own long-term resource planning and nationally recognized cost analyses showing that renewable energy continues to be among the most cost-competitive options for new electric generation.

Administrative proceedings often operate under more flexible evidentiary standards than traditional court proceedings. Even so, those standards do not eliminate the need for reliable evidence. When a publication presents factual conclusions without explaining how those conclusions were reached, and the sponsoring witness cannot explain or defend the underlying analysis, the Commission should carefully consider whether the exhibit deserves any evidentiary weight.
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As Arizona continues to make long-term decisions about reliability, affordability, and the future of the electric grid, those decisions should be based on transparent analysis, sound methodology, and credible evidence—not unsupported scorecards.

Today, AriSEIA filed a motion asking the Arizona Corporation Commission's Administrative Law Judge to recall APS Chief Operating Officer Jacob Tetlow for limited additional cross-examination.

During the APS rate case hearing on May 26, AriSEIA questioned Mr. Tetlow about APS's plans for the Cholla Power Plant after its coal units retire. Mr. Tetlow testified that APS did not have a definitive plan for the site, that multiple options remained under consideration, and that it was too early for a stakeholder process regarding the plant's future.
On July 2, however, APS announced plans to convert the Cholla Power Plant to natural gas.
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Because the announcement came while the rate case hearing is still underway and concerns the same subject addressed during Mr. Tetlow's testimony, AriSEIA has asked that he be recalled to answer limited questions about when APS made this decision, what planning had already occurred at the time of his testimony, and how the project fits within APS's resource planning process.