Tesla has entered into a long-term power purchase agreement (PPA) with ContourGlobal for the supply of approximately 1 TWh/year of renewable electricity from Project Sterling, a hybrid solar and battery storage project located in Arizona, US (ContourGlobal press release, 28/07/2026).
The agreement is described as one of the largest corporate solar-plus-battery PPAs ever concluded for a single facility in the United States, with electricity supplied by the largest renewable asset in ContourGlobal’s portfolio.
Project Sterling combines 509 MWp-450 MWac of solar PV capacity with a 360 MW/1.4 GWh battery energy storage system.
The project is connected to the Western Area Power Administration grid and will benefit from firm transmission rights into the California Independent System Operator (CAISO) electricity market.
Under the terms of the agreement, Tesla will receive around 90% of the facility’s annual electricity output, together with the associated renewable energy certificates (RECs).
Major off-site construction activities began in 2025, including the procurement of key equipment in June 2026.
On-site construction is scheduled to start later this year, while commercial operations are expected to commence in 2028. Once commissioned, Project Sterling will become ContourGlobal’s largest renewable energy asset.
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