Calpine celebrates 65 years of geothermal power generation at The Geysers, California
Calpine celebrates 65 years of The Geysers (source: Calpine)
Carlo Cariaga
29 Oct 2025
With 65 years of geothermal power generation, The Geysers in California remains one of the most important and productive geothermal fields in the world.
Calpine Corporation (Calpine) is celebrating the 65th anniversary of geothermal power generation at The Geysers, one of the world’s largest and most productive geothermal energy sites. This milestone reflects more than six decades of innovation, partnership and sustainable power generation in Northern California.
Since commercial operations began in 1960, The Geysers has been at the forefront of California’s energy transformation, producing reliable, around-the-clock renewable power using steam heated by the Earth’s core. Today, Calpine’s 13 geothermal power plants across the 45-square-mile terrain generate enough renewable electricity to power approximately 725,000 homes annually.
As part of the anniversary celebration, Calpine has published a very nice timeline of the geothermal history of The Geysers, covering early discovery by Native American tribes, the first attempts at geothermal power production and drilling in the 1920s, the first commercial-scale power plant in 1960, the gradual acquisition by Calpine, and recent efforts on capacity addition.
Earlier this year, 7 MW of power generation capacity was added to the Geysers through the North Geysers Incremental Development Project, which envisions a total expansion of 25 MW. This new capacity addition now supplies local electricity supplier MCE.
At the heart of The Geysers’ success are the people who develop, operate and maintain geothermal production. Calpine has nearly 300 employees and 150 contractors who live and work in Lake and Sonoma Counties. Their expertise and dedication to their craft have helped make The Geysers a global model for responsible geothermal development and a cornerstone of California’s renewable energy portfolio.
To commemorate the special milestone, Calpine donated $65,000 to the Clear Lake Environmental Research Center (CLERC), a community-based non-profit focused on protecting and restoring the Clear Lake watershed and surrounding ecosystems. Working across Lake and Sonoma Counties, CLERC coordinates wildfire prevention and habitat restoration efforts.
“The success of The Geysers over the past 65 years is a testament to the people who have cared for it: hardworking, committed individuals who view stewardship as both a duty and a privilege,” said Aimee Blaine, Calpine’s Senior Vice President, Geothermal Region. “Together with our partners and community, we have built a deep connection to each other and this land. Our shared pride in this work has helped The Geysers remain a global leader in geothermal energy production and environmental responsibility.”
The Geysers is one of several geothermal fields around the world that have been operating for more than 30 years. Just recently, Ahuachapan in El Salvador celebrated its 50th year anniversary.
Source: Calpine Corporation via PRNewswire
