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.

The Arizona Solar Energy Industries Association (AriSEIA) filed comments with the Arizona Corporation Commission supporting Trico Electric Cooperative’s proposed virtual power plant (VPP) program and urging the Commission to move it forward without further delay. The program would allow Trico to dispatch batteries already installed by its members during periods of peak demand, helping reduce purchased power and potentially defer costly grid investments. AriSEIA commended Trico for voluntarily proposing the program and for recent changes that reduced dispatches to no more than 1 per day and added an opt-out right for participating customers.

AriSEIA recommended several changes designed to improve participation and ensure the pilot produces meaningful results. Most importantly, compensation should be based on the power batteries actually deliver during VPP events rather than their installed inverter capacity. AriSEIA also recommended allowing leased and third-party-owned batteries and aggregators to participate, expanding eligibility regardless of a customer’s rate schedule, raising the proposed 1,000-customer enrollment limit, establishing clear limits on dispatch events and hours, and guaranteeing advance notice of events. Additional recommendations include standards-based equipment eligibility, protections against event-related recharging costs, greater flexibility for customers who rely on batteries for backup power, and an evaluation and reporting plan.
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The application has been pending since 2024, and AriSEIA urged the Commission not to allow another year to pass without action. Batteries installed throughout Trico’s territory represent existing capacity that could be helping the cooperative meet peak demand, yet no customers can participate until the tariff is approved. AriSEIA asked the Commission to approve the VPP now and, if changes are necessary, direct Trico to make them through a compliance filing within 60 days. A successful Trico program could put otherwise idle distributed storage to work for the grid while providing a model that other Arizona utilities can build upon.

AriSEIA joined Vote Solar and Solar United Neighbors in urging the Arizona Corporation Commission (ACC) to pause or reduce Tucson Electric Power’s (TEP) proposed 2026 reduction to its Resource Comparison Proxy (RCP), the rate used to compensate rooftop solar customers for excess electricity they send to the grid. TEP customers can pay more than 20 cents per kilowatt-hour during summer evening hours, while the proposed reduction would compensate solar customers just 4.6 cents per kilowatt-hour for electricity they provide to the grid.

The groups argued that reducing solar compensation makes little sense as Arizona faces rising electricity rates and record energy demand. TEP reached a new system peak of 2,502 megawatts on August 6, and rooftop solar helps reduce that demand while customer batteries can provide additional power during critical evening hours through TEP’s virtual power plant program. Making rooftop solar less affordable could slow investment in both solar and storage, ultimately increasing the need for utilities to build additional generation.
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Arizona’s solar industry also includes nearly 365 companies, employs almost 10,000 people, and has brought $24.1 billion in investment to the state. AriSEIA and its partners are asking the ACC to avoid the maximum RCP reduction this year, helping preserve customers’ ability to lower their energy bills while supporting Arizona jobs, businesses, and a more resilient electric grid. 

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) filed its Responsive Brief in Tucson Electric Power’s (TEP) pending rate case, urging the Arizona Corporation Commission to adopt rate designs that provide customers with clear price signals, protect customers from poorly designed demand rates, and expand access to energy storage and virtual power plants. AriSEIA argues that TEP has not justified key elements of its proposed rates and has failed to address evidence showing significant problems with its existing rate designs.
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AriSEIA highlighted new customer-level analysis showing that 52% of the more than 10,000 non-solar customers enrolled in TEP’s Residential Demand Time-of-Use rate would pay less on the standard Time-of-Use rate. Those customers are overpaying by an average of 21%, or approximately $215 per year. AriSEIA is asking the Commission to close the demand-based rate to new customers, notify existing customers who could save by switching rates, and require TEP to redesign its time-of-use rates so customers receive simpler and more actionable signals to reduce usage during periods of peak demand.
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The brief also urges the Commission to preserve and improve opportunities for commercial and industrial customers to use battery storage rather than allowing TEP to eliminate its existing commercial storage tariff. AriSEIA recommends expanding storage-specific tariffs, opening TEP’s virtual power plant program to non-residential customers, allowing third-party-owned systems to participate directly, and expanding the non-residential storage tariff pilot to 50 MW. These changes would allow more customers to use private investment in storage to reduce peak demand and provide benefits to TEP’s grid.

The Arizona Solar Energy Industries Association (AriSEIA) filed its reply brief with the Arizona Court of Appeals in its challenge to Arizona Corporation Commission Decision No. 81586, which eliminated net metering for commercial and industrial (C&I) customers of Sulphur Springs Valley Electric Cooperative. AriSEIA argues that the new tariffs conflict with the Commission’s existing Net Metering Rules.

At the center of the appeal is a straightforward question: can the Commission eliminate net metering for C&I customers through an individual rate case while its Net Metering Rules remain in effect? AriSEIA argues that the Commission has the authority to change its net metering policy, but it must first amend or repeal its existing rules through the required rulemaking process. The Commission’s authority to approve utility tariffs does not give it authority to approve tariffs that conflict with the substantive requirements of its own rules.
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The reply brief also rejects arguments that requiring the Commission to follow the rulemaking process would interfere with its constitutional ratemaking authority. The Commission adopted the Net Metering Rules and remains free to change them, but those rules remain binding until they are lawfully amended or repealed. AriSEIA is asking the Court of Appeals to vacate Decision No. 81586 and require the Commission to follow its existing Net Metering Rules.

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.