Utility Salt River Project, NextEra Resources bring online 100MW retrofit BESS at Arizona PV plant

December 20, 2023
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Arizona utility Salt River Project (SRP) has welcomed the start of commercial operations at a 100MW battery storage system, which has been installed at one of the company’s solar PV power plants.

SRP announced on Monday (18 December) that an official opening event had been held for the 4-hour duration (400MWh) battery energy storage system (BESS) that is now plugged into Saint Solar, a 100MW PV plant in the city of Coolidge, Pinal County.

Saint Solar went online in 2020 and is notable for serving SRP’s 11 most energy intensive customers with clean energy, including Walmart and the City of Phoenix, through a programme called Sustainable Energy Offering that allows corporates and other large energy consumers to directly invest in energy from solar projects.

The solar plant was delivered by developer NextEra Energy Resources, which also delivered the new battery system. NextEra operates the PV plant and will also be responsible for operating the BESS.

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The project builds on a relationship between utility and developer that has already seen SRP contract with NextEra Energy Resources for the Sonoran Energy Center solar-plus-storage project. The developers announced the Sonoran Energy Center in 2019 and is expected to go online soon, featuring 260MW of PV paired with a 1GWh battery storage system

Arizona, as a state, has become one of the US’ leading adopters of renewables. While 42% of its electricity was generated from gas and about 12% from coal in 2022, nearly all of the remainder came from hydroelectric and solar PV, according to figures from the US Energy Information Administration (EIA).

The recent and continued growth of solar has driven the state to also be one of the country’s leaders in battery storage, albeit some way behind standout leaders California and Texas.

BESS containers and power conversion system (PCS) equipment at the site. Image: NextEra Energy Resources.

The state’s utilities are playing a major role in storage adoption. Earlier this month, social media giant Meta, SRP and Ørsted announced a power purchase agreement (PPA) for a 300MW solar PV project with 1,200MWh battery storage was announced.

In October, developer Plus Power secured financing for two Arizona projects for which it has signed 20-year energy storage tolling agreements with SRP, including the 250MW/1,000MWh Sierra Estrella BESS, at which construction began in April this year.

SRP is bringing online 1,100MW of energy storage resources by the end of 2024, and is seeking to add a further 1,500MW of battery storage by 2035, as well as 1,000MW of long-duration pumped hydro energy storage (PHES). It is also looking to add 6,000MW of new large-scale solar PV by that time, and 1,000MW of other renewables, anticipating growth in demand for electricity in its service area of about 25% by the end of 2030.

In other recent Arizona utility BESS activity, Tucson Electric Power (TEP) is currently developing a build-own-operate 200MW/800MWh BESS project, while Arizona Public Service (APS) signed a 20-year tolling agreement of its own with developer Strata Clean Energy for a 255MWh/1,000MWh BESS.

Energy-Storage.news’ publisher Solar Media will host the 6th Energy Storage Summit USA, 19-20 March 2024 in Austin, Texas. Featuring a packed programme of panels, presentations and fireside chats from industry leaders focusing on accelerating the market for energy storage across the country. For more information, go to the website.

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