AUSTIN, Texas — Tesla signed two large solar power-purchase agreements in a single day this week, locking up roughly 649 megawatts of new clean generation to feed its factories, Supercharger network and fast-growing energy business.
The centerpiece is Project Sterling, a 509-megawatt solar farm in Arizona paired with a 360-megawatt battery system rated at 1.4 gigawatt-hours of four-hour storage. Tesla agreed to buy about 90% of the plant's output from developer ContourGlobal, in one of the largest solar-plus-storage corporate agreements ever struck for a single U.S. facility, as first detailed by Electrek. Hours earlier, Tesla confirmed a separate deal with developer Zelestra for the entire output of a 140-megawatt solar farm in Texas.
Power for a Bigger Machine
The timing is not an accident. Tesla's energy appetite is climbing as it stands up new production lines, expands its Supercharger footprint and scales the compute behind Full Self-Driving and Optimus. Signing long-term PPAs lets Tesla fix a chunk of its future electricity costs while backing projects that add firm, dispatchable clean power to the grid.
Project Sterling alone is expected to generate more than 1 terawatt-hour of electricity a year — comparable to the annual residential consumption of a city of roughly 100,000 to 120,000 people. Because the plant pairs solar with four-hour batteries, it can shift midday generation into the evening peak, exactly the kind of round-the-clock profile that heavy industrial buyers need.
Storage Is the Common Thread
Both deals lean on the same insight that has powered Tesla's energy division to record deployments: solar is cheap, but solar plus storage is bankable. The battery pairing at Project Sterling turns an intermittent resource into something closer to a dependable generator, and it dovetails with Tesla's own Megapack business, which just posted its second-largest quarter ever. Tesla's record 13.5 GWh of energy-storage deployments in Q2 showed how central grid-scale batteries have become to the company's growth story.
Construction on Project Sterling began in 2025, and commercial operation is targeted for 2028. The plant connects to the Western Area Power Administration grid and holds transmission rights that reach into California's CAISO market, giving Tesla flexibility in how the power is routed.
A Pattern, Not a One-Off
Two utility-scale agreements in one day underscores how aggressively Tesla is contracting for clean electricity ahead of its next wave of expansion. The company has spent the past year knitting together generation, storage and demand — from Megafactories to the Supercharger network that turned the Tesla Diner into the world's busiest Supercharger in its first year.
Expect more of these deals. With factories multiplying and AI compute demand rising, Tesla has every incentive to keep locking in low-cost, storage-backed solar years in advance. If Project Sterling is the template, the company's clean-energy buildout is only accelerating — and 2028 is shaping up to be the year a lot of that contracted power finally comes online.
