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 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.

FOR IMMEDIATE RELEASE
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PHOENIX, Ariz. – June 16, 2026 – The Arizona Court of Appeals has vacated the Arizona Corporation Commission's decision approving Arizona Public Service's (APS) solar-specific charges, including the Grid Access Charge (GAC) and the Legacy Solar Rate Increase (LSRI), marking a significant victory for Arizona's rooftop solar customers and the rule of law.

The Court concluded that the Commission's decision cannot stand and remanded the matter for further proceedings after finding that the process used to adopt the charges deprived affected parties of a meaningful opportunity to challenge them.

Importantly, the Court recognized that APS never proposed the solar-specific charges in its rate application and instead sought a uniform residential rate increase. The solar charges were introduced only after the evidentiary record had closed, leaving customers and stakeholders without an opportunity to fully address the proposal.

"This decision confirms what AriSEIA has argued from the beginning: Arizona's rooftop solar customers should not be singled out for discriminatory charges that were never properly proposed or supported," said Autumn Johnson, Executive Director of AriSEIA. "The Court has now vacated those charges, and the Commission should act quickly to eliminate both the Grid Access Charge and the Legacy Solar Rate Increase in the pending APS rate case."

The Commission itself previously found that APS had not demonstrated that rooftop solar customers impose unique costs warranting separate treatment. In this appeal, the Court further recognized that APS did not seek approval of the solar charges in the underlying case and that affected parties lacked meaningful notice that such charges were under consideration.

Rather than continue to defend charges that have now been vacated by the Court of Appeals, AriSEIA urges the Arizona Corporation Commission to use the ongoing APS rate case to permanently eliminate the use of a site load cost of service study and the GAC and LSRI and restore a fair, transparent, and evidence-based approach to ratemaking.

"The Commission has an opportunity to put this issue behind it," Johnson said. "Arizona should encourage customer investment in rooftop solar, not burden it with unlawful and discriminatory charges that have now been rejected by the courts."

For more than four years, AriSEIA has worked alongside its members, national partners, fellow appellants, and Arizona solar customers to challenge these charges and advocate for policies that are lawful, transparent, and support customer choice.

About AriSEIA
The Arizona Solar Energy Industries Association (AriSEIA) is a statewide nonprofit trade association representing the solar, storage, and electrification industry. AriSEIA's mission is to develop and support policies that create opportunities to advance Arizona's economy through solar energy, storage, and electrification. AriSEIA advocates for sustainable job creation in the deployment of solar and complementary technologies and collaborates with stakeholders to encourage utilization of Arizona's greatest natural resource: the sun.
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Media Contact
Autumn Johnson
520-240-4757
[email protected]

AriSEIA filed direct testimony in the Arizona Public Service rate case. We make the following recommendations:

​Site Load COSS

• Discontinue the use of the Site Load COSS and instead direct APS to use a Delivered Load COSS going forward.
• In the alternative, direct APS to make the following modifications to the Site Load COSS
  • Use AriSEIA’s recommended methodology to determine demand reductions associated with Residential DG solar.
  • Use the same transmission cost allocation in the Solar Credit as APS does in its FERC tariff filings.
  • Do not “charge” solar customers for revenue shortfalls associated with transmission rates or EPR-6 or RCP purchases.
  • Utilize a marginal avoided energy cost rate instead of the average fuel and purchased price rate to value energy generation.
• Recognizing that the cost shift in the Site Load COSS disappears after fixing the methodological errors above, cancel the GAC and LSRI and direct APS to recalculate its rates without these adjustments.

DG Study

• Find that the Company did not follow the Commission’s directive to provide sufficient information in its application for intervenors to “scrutinize” the DG Study.
• Reject the results of the DG Study based on the myriad methodological flaws identified in my testimony.
• Do not direct the Company to perform the DG Study going forward.

SP Tariff

• Shorten the on peak window from 4 PM to 9 PM to 5 PM to 8 PM.
• Expand the SP Tariff to the E32-S and E-32M rates.
• Adjust variable cost recovery to 80% energy / 20% demand.
• Adopt AriSEIA’s “3:2:1’ variable energy rate design.
• Update its marketing materials to highlight the availability and benefits of this rate.

VPPs

• Expand the VPP program to non-residential customers.
• Update its marketing materials to highlight the availability and benefits of this rate.

AriSEIA filed a reply brief with the Arizona Court of Appeals today in the ongoing appeal from Arizona Public Service's last rate case, in which they imposed a discriminatory fee on rooftop solar customers. This is expected to be the last round of briefing and oral argument should be held in early 2026.

AriSEIA appealed the Arizona Corporation Commission (ACC) decision that allowed Arizona Public Service (APS) to impose a discriminatory fee on all of its rooftop solar customers, called the Grid Access Charge. Briefs were due to the Court of Appeals on July 18, 2025. Another round of briefs are due in September. You can read our brief here: 

APS has been charging a punitive and discriminatory fee against residential rooftop solar customers for almost a year and AriSEIA has been fighting it every step of the way. Today we joined with the Solar Energy Industries Association and two individual ratepayers in filing for an appeal with the Arizona Court of Appeals.

AriSEIA filed direct testimony today in APS' rate case rehearing against the new fees imposed on solar customers this year. Those fees were imposed with absolutely no evidence presented in the original case, based on a cost of service study that was rife with errors and anomalies. Not only is the fee unfounded, arbitrary/capricous, and discriminatory, but our analysis reflects that actually solar customers are subsidizing non-solar customers. The hearing is scheduled for the week of October 28th.

APS sent a misleading customer notice about the solar charge rehearing in August. That notice implied that only some solar customers are impacted by the rehearing, when potentially all solar customers are impacted. AriSEIA has asked APS to reissue the notice.

​FOR IMMEDIATE RELEASE
 
Contact:
Autumn Johnson
(520) 240-4757
[email protected]
 
Phoenix, AZ – Arizona Public Service (APS) is once again advocating for a tax on all solar customers in its service territory. APS seeks a fee increase that amounts to a tax on APS’ nearly 200,000 solar customers where they pay 15% more than all other residential customers. The Arizona Corporation Commission (ACC) recently ruled that this solar tax increase was enacted without proper public notice and deprived parties of due process and ordered a rehearing to fix these important constitutional issues.
 
The Arizona Solar Energy Industries Association (AriSEIA) has opposed this discriminatory solar tax that raises costs for families all over Arizona.  AriSEIA asked the ACC to reconsider the APS rate case to evaluate the fairness of this fee and cure due process deficiencies. The ACC granted AriSEIA’s rehearing request, but APS has since fought to exclude approximately 74,000 solar customers on “Legacy Rates” from the rehearing and has fought to limit the evidence the ACC can even consider in determining if the fee is legal. Today the ACC issued a decision siding with APS on these two issues. This decision means that there will not be a fair hearing on this new solar tax and that hundreds of thousands of Arizonans that invested their hard-earned money in solar will not be treated fairly.
 
“APS has proven time and again that they will always take whatever actions they can to try and penalize solar customers,” said Autumn Johnson, Executive Director of AriSEIA. “APS fights against rooftop solar for one reason: money. When customers exercise their right to install solar, APS has less justification to build new powerplants that they earn a profit on. Solar customers use their own money to add energy to the grid and reduce peak energy demand, saving all customers money. And these customers increasingly also install batteries that provide APS with power at the exact moment they need it most. Yet, APS, time and again, seeks to hurt solar customers at every opportunity.”
 
The ACC is conducting another hearing in November about these new APS-backed solar taxes that only impact solar customers. It is unclear from the decision today whether or not that hearing will resolve any of the legal concerns of AriSEIA or solar customers, which led to the request for a rehearing in the first place. More information can be found in Docket No. E-01345A-22-0144.
 
About AriSEIA: The Arizona Solar Energy Industries Association (AriSEIA) is the State’s leading trade association dedicated to promoting the adoption of solar, storage, and electrification technologies. AriSEIA advocates for policies that support the growth of Arizona’s solar industry and provides resources and education to ensure that solar energy continues to thrive in the State.