AriSEIA Files the First Brief in the TEP Rate Case

Read the Brief

Today, AriSEIA filed its closing brief in the Tucson Electric Power (TEP) rate case, outlining recommendations to modernize rate design, improve customer access to energy storage and virtual power plants, strengthen regulatory oversight, and protect customers from unjustified costs.

At the heart of AriSEIA's case is a simple principle: utility rates should help customers make informed decisions that reduce costs and strengthen the grid.

The evidence presented during the hearing showed that TEP's current time-of-use rates are overly complex, produce limited customer participation, and fail to send meaningful price signals that encourage customers to shift energy use away from peak demand. AriSEIA recommends a simpler, more effective rate structure with stronger incentives that better reflect the costs customers impose on the electric system.

The brief also urges the Arizona Corporation Commission to expand opportunities for commercial and industrial customers to participate in battery storage and virtual power plant programs. Rather than eliminating existing storage tariffs without replacement, AriSEIA recommends that TEP develop viable pathways for businesses to deploy customer-sited storage that improves grid reliability while reducing system costs.

Beyond rate design, AriSEIA asks the Commission to carefully scrutinize several components of TEP's requested revenue requirement, including its proposed return on equity and certain shareholder-related expenses, to ensure customers pay only costs that are just, reasonable, and supported by the record.

Finally, the brief recommends important procedural improvements if the Commission adopts an Annual Rate Adjustment Mechanism (ARAM). Those recommendations are designed to preserve transparency, meaningful public participation, and Commission oversight while ensuring future rate adjustments remain fair and evidence-based.
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The Arizona Corporation Commission's decision in this case will shape electric rates, customer programs, and distributed energy opportunities for years to come. AriSEIA appreciates the opportunity to participate in this proceeding and looks forward to the Commission's decision.