ContourGlobal on July 28 announced the execution of a large-scale power purchase agreement with Tesla for Project Sterling, a hybrid solar and battery energy storage project located in Arizona’s Western Area Power Administration region, with firm transmission rights into the California ISO market.
The agreement with Tesla covers ~1 TWh per year, representing around 90% of the project’s as-generated annual output, and will provide long-term renewable energy.
Project Sterling is a large-scale hybrid project combining 509 MWp/ 450 MWac of solar PV with 360 MW/1.4 GWh of battery energy storage capacity, with an expected annual energy output of more than 1.1 TWh.
Once operational, it will be ContourGlobal’s largest renewable asset to date.
Acquired in the development stage in December 2024, the project has since been reshaped by ContourGlobal’s in-house Business Development, Engineering, Procurement, and Commercial teams specifically to meet the offtaker’s requirements, it noted.
Substantial construction activity began in 2025 through off-site physical work of significant nature, including procurement of major equipment in June.
On-site construction is scheduled to commence later in the year, and commercial operation is targeted for 2028.
Located in Arizona and physically connected to the WAPA grid, Project Sterling holds firm point-to-point transmission rights to access California’s CAISO and will be pseudo-tied, enabling it to serve Tesla’s needs, the company said.
