Tesla Buys 90% of 509 MW Arizona Solar-Storage Plant
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- Tesla signed a long-term PPA for 90% of Project Sterling's output — a 509 MW solar + 360 MW battery plant in Arizona being built by ContourGlobal, with the project expected online in 2028.
- ContourGlobal, owned by private equity firm KKR, acquired the project in late 2024 and calls it the largest renewable asset in its portfolio; the company will retain and trade the remaining 10% of output.
- The plant connects to the Western Area Power Administration grid, giving it access to California markets; the 360 MW battery is a four-hour system totaling roughly 1,440 MWh of storage.
- Tesla signed a separate deal earlier the same day with Spanish developer Zelestra for the full output of a 140 MW solar farm in Texas — bringing Tesla's single-day contracting to over 640 MW of third-party solar plus 360 MW of battery storage.
- Tesla manufactures the Megapack grid battery and is building a 100-GW solar panel factory in Texas, yet purchased the Arizona project's solar and storage from a third-party developer rather than building it itself.
- The Arizona PPA will lock Tesla into clean power well into the 2030s as factory and AI compute loads grow, following the same playbook used by Meta and Google.
Why it matters: Tesla's power needs are scaling fast — from Gigafactory Texas to expanding AI compute — and locking in 640+ MW of solar plus 360 MW of battery storage in a single day reflects how urgently it needs to hedge grid costs before AI-driven demand tightens US power markets further into the late 2020s.
