Construction nears on SRP large-scale battery energy storage project in Arizona


Officials from Salt River Project (SRP), Plus Power LLC, and the City of Avondale took part in a ceremonial groundbreaking to kick off construction at Sierra Estrella Energy Storage, what is expected to be the largest standalone battery facility in Arizona once online.

The facility will store up to 250 MW / 1 GWh and will SRP customers during times of peak electricity demand.

“This facility will have enough stored energy to power more than 56,000 average size homes for a four-hour period,” said Grant Smedley, director of resource planning at SRP. “Battery storage can help provide energy to the grid when other resources may not be available and is part of SRP’s overarching strategy to meet rising energy demand while reducing carbon emissions.”

The Sierra Estrella facility is one of two battery storage projects SRP announced in fall of 2022 with Plus Power, with both projects scheduled to come online by summer of 2024. The other, a 90 MW / 360 MWh project is called Superstition Energy Storage, which is planned for Gilbert, Ariz. When these projects are complete, SRP expects to surpass  1.1 GW of battery storage by 2024.

The storage facilities are being designed and built by Houston-based Plus Power, a battery energy storage systems provider with a pipeline of over 100 GW across 28 states. Plus Power has designed the Sierra Estrella Facility to use Tesla lithium-ion batteries, a technology that have caught fire in the past. In September 2022, fire broke out at a PG&E facility in Monterey County, Calif. where at least one of the Tesla Megapack systems caught fire.  In 2021 a Tesla Megapack also caught fire in the Victorian Big Battery in Moorabool, Australia. Plus Power reports that it will design the Arizona projects to updated national codes and standards for battery energy storage systems, which incorporate lessons learned from incidents at other battery facilities. Plus Power has also engaged with both the Gilbert and Avondale Fire Departments to prepare a thorough emergency response plan. In the coming months the two organizations will conduct onsite training to provide safety planning to local first responders throughout construction and operation.

“Avondale is proud to partner with SRP and Plus Power to welcome the Sierra Estrella Energy Storage facility which will be a valuable asset to our community for decades to come,” said Veronica Malone, Avondale councilmember. “The project will provide necessary power to the region with no onsite air polluting emissions, will incorporate the latest safety standards, and has been designed with thorough planning and preparation.”

Sierra Estrella Energy Storage is expected to generate 30 to 40 construction jobs throughout its development and to expand the Avondale district property tax base.

SRP is a community-based, not-for-profit public power utility that was founded in 1903 as the Salt River Valley Water Users’ Association. Made up of local ranchers and farmers, the association’s mission was to see the Valley flourish, and together, they offered up their land as collateral for federal funds to build Roosevelt Dam. Today SRP reports that it supplies around 750,000 acre-feet of water every year and delivers power to more than 1 million customers. In 2017 SRP adopted its 2035 Sustainability Goals, which commit to reducing carbon (from 2005 levels) by more than 65% by 2035 and 90% by 2050. SRP has also closed the largest coal plant in the Western U.S. and will have retired approximately 2.6 GW of coal-fired generation by 2032. The company anticipates that by 2025, nearly half of all retail energy delivered to SRP customers will come from carbon-free resources.

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