In the Arizona desert, a new kind of power plant is taking shape that could change how America gets its electricity. Tesla and ContourGlobal, an international energy company, recently signed a landmark agreement for something called Project Sterling — a massive facility that will generate enough clean electricity to power hundreds of thousands of homes every single year.
The numbers are striking. Project Sterling will produce 1,000 gigawatt-hours of renewable energy annually — that's 1 terawatt-hour, a unit so large it sounds almost made up. To give you a sense of scale, that's enough electricity to meet the needs of a medium-sized American city. The plant will combine 450 megawatts of solar power with a battery system that can store 1.4 gigawatt-hours of energy. In plain terms, those batteries can hold enough electricity to power roughly 100,000 typical American homes for several hours — even after the sun goes down.
The deal represents one of the largest solar-plus-battery corporate power agreements ever signed from a single plant in the United States, according to clean energy analysts. Tesla will purchase about 90 percent of everything the plant generates under a long-term contract that bundles electricity with renewable energy certificates.
"This is our biggest power purchase agreement ever — and one of the largest of its kind in U.S. renewable history," said Antonio Cammisecra, chief executive of ContourGlobal, in a statement announcing the deal. "Securing it with an iconic customer like Tesla, a true symbol of the global energy transition, is a testament to our ability to deliver tailor-made solutions."
The project sits in Arizona and connects to the Western Area Power Administration grid, with transmission rights that will allow the electricity to flow into California's power market. ContourGlobal acquired the project in late 2024 and has since redesigned it specifically to meet Tesla's energy needs. Construction work began in 2025 with equipment procurement and off-site preparation. On-site groundbreaking is planned for 2026, with the plant expected to start delivering electricity by 2028.
Once operational, Project Sterling will become the largest renewable energy asset in ContourGlobal's global portfolio — a significant milestone for a company that only started running its first American renewable plant in 2025. The agreement shows how tech giants like Tesla are increasingly turning to direct partnerships with clean energy developers to power their operations with genuinely green electricity, locking in supplies for years to come.