Calpine, a business unit of Constellation, has completed a 25 MW expansion at The Geysers geothermal complex in Sonoma County, California, increasing the site’s output of around-the-clock renewable electricity and reinforcing its role as a key source of reliable clean energy for the state.
The expansion comes as California looks for more reliable renewable supply to meet rising electricity demand. Calpine said the work builds on its earlier addition of a 38 MW battery storage system at the site in 2024, reinforcing The Geysers’ role as a steady source of baseload clean power.
Of the new capacity, 18 MW will go to Clean Power Alliance, while 7 MW that came online last year are being supplied to MCE. Both buyers are relying on geothermal energy for dependable renewable electricity that is not tied to weather or time of day.
Calpine said the project was completed under a Project Labor Agreement with local unions, underscoring the construction and workforce piece of the expansion as well as the energy one.
The Geysers, the world’s largest operating geothermal complex, has been producing clean power in California for more than 65 years.
