AriSEIA is partnering with the Solar Energy Industries Association (SEIA) to intervene in the Tucson Electric Power (TEP) 2022 General Rate Case. TEP filed the rate case in June 2022, testimony is due in January 2023, and the hearing is expected to start in late March 2023.
BEFORE THE ARIZONA CORPORATION COMMISSION
Lea Márquez Peterson – Chairwoman
IN THE MATTER OF THE APPLICATION OF ARIZONA PUBLIC SERVICE COMPANY FOR A HEARING TO DETERMINE THE FAIR VALUE OF THE UTILITY PROPERTY OF THE COMPANY FOR RATEMAKING PURPOSES, TO FIX A JUST AND REASONABLE RATE OF RETURN THEREON, AND TO APPROVE RATE SCHEDULES DESIGNED TO DEVELOP SUCH RETURN.
Docket No. E-01345A-19-0236
Arizona Solar Energy Industries Association (AriSEIA) Comments on Arizona Public Service (APS) Efforts to Comply with Order Relating to Rate Schedule E-32 L Storage Pilot in Decision No. 78317
We appreciate the Commission’s decision to include AriSEIA/SEIA in collaborative discussions with APS on the rate design elements and intended success of the E-32 L Storage Pilot (SP) plan.
The E-32 L SP tariff was established in December 2017 as a result of APS’ previous rate case with the intention to evaluate the opportunity of large-scale, behind-the-meter energy storage solutions as a value-added benefit to the grid while allowing for high demand (as determined by 15-minute interval kilowatt readings) customers to benefit from peak shaving. Due to several issues, including poor rate tariff mechanics and imbalanced Cost of Service (COS) formulas (notably with lower per-kW rates than the non-pilot, base E-32 L rate tariff), the pilot program offering did not facilitate subscription from any customers.
Decision No. 78318 and Current Status
AriSEIA/SEIA offered testimony that the E-32 L SP rate schedule required re-evaluation. The Commission ordered APS to do the following:
Subsequent to the order, APS filed its revised rate tariff on December 1, 2021, and held its first stakeholder engagement meeting on February 23, 2022. AriSEIA/SEIA maintains that while APS is complying with the letter of the order, the spirit of the decision is being left to stakeholders to enforce.
Key Issues on Proposed E-32 L SP Rate Plan and Discussion
It is AriSEIA’s understanding that the intent of this pilot program is to facilitate adoption of energy storage for APS’ large commercial customer class up to 35 megawatts (MW) of installed capacity, and to that end, we submit the following feedback for consideration:
Due to the nature of variability between customer load profiles (predictability of peaks depending on facility type), the economics of energy storage vary significantly from project-to-project. Furthermore, the value proposition (i.e., return on investment), depends on whether or not a customer can monetize federal tax incentives directly. Although pending federal legislation includes a change which provides tax credits to ‘storage only’ projects, the current Internal Revenue Code only allows energy storage customers to claim available tax incentives when the storage systems are charged by solar energy (at least 75%) throughout the operational year. Given that many APS E-32 L customers are tax-exempt and the fact that this tariff is unlikely to support solar projects in conjunction (i.e. tax credits will not be available), we believe it is critical that the tariff be designed in a way that provides sufficient economic incentive to pursue pilot projects for all interested customers.
Energy storage systems represent significant investments and require a precise and reliable method for return on investment. We submit that the spirit of the Order requires that APS demonstrate a thoughtful and comprehensive approach to the design of the E-32 L SP rate tariff, and we recommend an approach that leverages optionality and increased on-peak vs. off-peak differentials.
As it stands, it is AriSEIA’s position that the current E-32 L SP rate plan will not facilitate any adoption toward the cap of 35 MW without substantial changes, and we recommend the Commission direct APS to issue revised rate tariff options that will provide further opportunities for customer adoption.
We thank the Commission and its staff for the opportunity to submit these comments.
Respectfully submitted this 6th day of May, 2022.
/s/ Autumn T. Johnson
Arizona Solar Energy Industries Association (AriSEIA)
/s/ John Mitman
Arizona Solar Energy Industries Association (AriSEIA)
 See APS 2019 Rate Case, Docket No. E-01345A-19-0236, Decision No. 78317, available here https://docket.images.azcc.gov/0000205236.pdf?i=1650001754509.
 See APS 2017 Rate Case, Docket No. E-01345A-16-0036, available here https://edocket.azcc.gov/search/docket-search/item-detail/19348.
 National Renewable Energy Laboratory, Identifying Potential Markets for Behind-the-Meter Battery Energy Storage: A Survey of U.S. Demand Charges, available here https://www.nrel.gov/docs/fy17osti/68963.pdf.
 Southern California Edison, Schedule TOU-8 Time-of-Use - General Service – Large (Option E), available here https://www.sce.com/regulatory/tariff-books/rates-pricing-choices and included as Attachment A.
 National Renewable Energy Laboratory, Storage Futures Study, available here https://www.nrel.gov/analysis/storage-futures.html.
 National Renewable Energy Laboratory, Federal Tax Incentives for Energy Storage Systems, available here https://www.nrel.gov/docs/fy18osti/70384.pdf.
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