Stem and AEPCO implement storage and solar project for member cooperative in Arizona

The project strengthens Stem’s growing position in the public energy sector; helps Sulfur Springs Valley Electric Co-op provide its members with reliable, clean energy

Stem (NYSE: STEM), a global leader in AI-powered clean energy solutions and services, and Arizona Electric Power Cooperative (AEPCO), a not-for-profit member-owned electric power generation and transmission (G&T) cooperative, in partnership with Prometheus Power (Prometheus), a national renewable energy producer, today announced the successful implementation of a storage and solar co-location project to help deliver clean and reliable energy to distribution cooperatives and public members of the energy sector.

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Photo credit: Arizona G&T Cooperatives (AzGT)

Photo credit: Arizona G&T Cooperatives (AzGT)

The project for Sulfur Springs Valley Electric Co-op (SSVEC), an AEPCO member, includes a 40 MWh energy storage system and an existing 20 MW photovoltaic (PV) system that Atena will integrate


, Stem’s award-winning AI-powered clean energy software that enables continuous operation and monitoring of your storage system for maximum efficiency on one unified platform. The SSVEC project is the first of three similar-sized implementations that Stem will collaborate on with Prometheus to provide Stem services to other AEPCO management cooperatives. All three projects are expected to be available online by the end of the year.

“More than 900 electric cooperatives in 48 states make up the largest electric grid in the United States. This segment is expected to be one of the fastest-growing segments of the FTM market by the end of this decade and is projected to account for over 20% of all future storage deployments,” said John Carrington, CEO of Stem. “Stem’s unique combination of software, hardware and AI-powered services enables cooperatives and their members to increase the value and returns of large-scale projects. We are excited to bring our proven capabilities and market experience to AEPCO and its members.”

“As part of our Reliable Energy Plan, AEPCO is focused on strategic investments in renewable energy assets and battery energy storage systems (BESS) to fundamentally enhance, diversify and strengthen the AEPCO portfolio,” said Patrick Ledger, AEPCO executive vice president and CEO. “With Stem’s proven solar and storage solutions and expertise, we can provide economies of scale for larger projects, allowing our member cooperatives to benefit from the flexibility and reliability of new clean energy resources that will significantly reduce costs and provide more reliable clean energy for enterprises. the communities we serve.”

“As Arizona’s largest cooperative, SSVEC has worked diligently to diversify our energy portfolio from over 80% of energy generated from coal in 2016 to just 25% in 2023, with an estimated 18% generated from renewable sources. These efforts help provide SSVEC members with greater energy independence, reliability and price stability, with the overarching benefit being a cleaner environment,” said Jason Bowling, SSVEC CEO. “Working with AEPCO and Stem to ensure the successful deployment and optimization of our renewable energy assets will help SSVEC continue to deliver on our commitments to provide our 53,000 members with reliable, affordable energy.”

“We are honored to have played a key role in the construction of this monumental facility for SSVEC,” said Rohit Garg, Prometheus Manager. “With our development expertise, we are confident that this project will set a new standard for cooperatives deploying renewable energy assets on an industrial scale, contributing to the adoption of sustainable practices in the energy sector. We look forward to working with Stem to implement future projects for AEPCO.”

These follow Stem’s recent wins on collaborative projects, including a 23 MW solar and 60 MWh storage project for Mohave Electric Cooperative (MEC), an AEPCO distribution cooperative, and a 313 MWh standalone energy storage project in cooperation with Ameresco for a large cooperative client op. Stem has booked more than $1 billion in contracts related to its growing segment of the municipal and cooperative services market. AEPCO will soon hold a ribbon cutting ceremony in Sahuarita, Arizona on June 13, 2024.

Learn more about AEPCO’s clean energy strategies in Stem’s upcoming webinar, “AEPCO Leads in Cost Reduction and Improved Reliability for Members,” register at -aepco/.

About Stem

Stem (NYSE: STEM) provides clean energy solutions and services that maximize the economic, environmental and resiliency value of energy assets and portfolios. Stem’s leading AI-powered enterprise software platform, Athena


enables organizations to deploy and unlock value from clean energy resources at scale. Powerful applications, including AlsoEnergy’s PowerTrack, simplify and optimize asset management and connect the ecosystem of owners, developers, assets and markets. Stem also offers integrated partner solutions that can improve returns on energy projects, including storage, solar and charging for electric vehicle fleets. More information can be found at


AEPCO is a provider of generation, transmission and power services to electric distribution cooperatives and utilities in Arizona, California and Nevada. AEPCO, based in Benson, Arizona, works with its sister organization, Sierra Southwest Cooperative Services, Inc. (Sierra) under the umbrella of Arizona G&T Cooperatives. AEPCO owns and operates the Apache Generating Station located in Cochise County, which has been operated by AEPCO since 1961 and is equipped with existing natural gas and electricity transmission infrastructure. More information about AEPCO and its future projects can be found at

Source: Stem, Inc.

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