A utility-scale solar plant converts sunlight into electricity using photovoltaic (PV) modules and delivers power to the grid through inverters and substations. These projects are designed to supply clean energy at a scale that supports cities, industry, and large commercial demand. 

A BESS stores electricity so it can be delivered later, making solar power more flexible. Pairing solar with batteries helps shift renewable energy into evening hours, reduce curtailment, support grid stability, and improve the overall value of clean generation. 

A hybrid solar PV + BESS plant is a renewable power facility that combines solar generation and battery storage to deliver flexible, reliable, and higher‑value electricity to the grid or end users. 

“4-hour” storage refers to a battery system designed to discharge at its rated power for roughly four hours. This duration is commonly used to meet peak demand, stabilize grids with high renewable penetration, and provide predictable dispatch during critical hours.

By combining clean generation with fast-responding storage, hybrid projects can provide more dependable delivery during non-solar hours and help manage rapid demand changes. This improves reliability in regions experiencing load growth and electrification. 

Project Sterling is a large‑scale hybrid solar photovoltaic and battery energy storage project located in Mohave County, Arizona. It combines approximately 508 MWp of solar generation with 360 MW of battery storage and is designed to deliver more than 1 TWh of electricity per year. The project has completed all discretionary approvals and is scheduled to begin on‑site construction in 2026, with commercial operations planned for 2028. 

Sterling supports Arizona’s role within the Western Interconnection by delivering clean, reliable power through existing grid and market structures. Physically interconnected to the Western Area Power Administration (WAPA) system and delivering energy into CAISO, the project strengthens regional grid reliability while relying on private capital and a long-term power purchase agreement (PPA) rather than regulated retail tariffs. The PPA secured for this facility is with a tier‑one global industrial off taker and among the world’s largest corporate buyers of long‑term renewable electricity contracts, and it will be one of the largest, if not the largest, solar-plus-battery storage corporate PPA ever signed from a single plant in U.S. renewable energy history.