Tesla, ContourGlobal enter PPA for 1.4 GWh of BESS with solar in Arizona

Tesla has agreed to buy most of the power from a large new solar-plus-battery project being built in Arizona by ContourGlobal. The project, called Sterling, pairs 509 megawatts of solar panels with a 360 MW/1.4 gigawatt-hour battery system (batteries that store extra power to use later, when the sun isn't shining). Under the deal, Tesla will purchase about 1 terawatt-hour of electricity a year, roughly 90% of what the project produces, to supply its operations in California.

This is a large-scale commercial power deal, not a residential program, so it does not offer homeowners a rebate or direct way to sign up. But it points to a broader trend worth knowing about: big batteries paired with solar farms are increasingly used to store daytime solar power and deliver it later, including across state lines. Arizona's project will connect to Arizona's grid but is also linked to California's grid, letting stored solar power move to where it's needed.

Construction on-site is set to begin later this year, with the project expected to be fully operating by 2028. ContourGlobal, which also has projects in Chile, Europe, and the UK, called this its largest power deal to date. For homeowners, the takeaway is mostly about where the country's electricity is heading: more solar paired with storage, which can mean cleaner and steadier power on the grid over time, even if this particular project itself has no direct home-upgrade angle.