In northwestern California, miles below the crust of the Earth, there is a natural and clean energy source that can be converted into enough electricity to power 725,000 homes. That energy source is steam.
About a quarter million years ago steam began erupting from a hot water geothermal reservoir deep within the Mayacamas Mountain Range. Tens of thousands of years prior, a 1400-degree Fahrenheit plume of molten magma shot upward toward the Earth’s surface. Maintaining high temperatures, that magma boiled water as it seeped through fractures in the rock. Now, thousands of years later, that geothermal resource is the primary component of the single largest geothermal electrical operation in the world, called The Geysers.
For 65 years, The Geysers, now owned and operated by Calpine Corporation, has been generating renewable power using steam heated by the Earth’s core.
For nearly the first 40 years of power generation at The Geysers, the local investor-owned utility managed operations, producing 11 megawatts of electricity at the start. By the time the ’90s rolled around, steam production began to decline due to overuse and a lack of water supply replenishing the reservoir. Sustaining operations required significant investment –– a challenge for the utility, which was shifting its focus more toward the transmission and distribution of electricity.
At the same time, California was restructuring its energy market, opening a door for independent power generators, like Calpine, to purchase generation assets from utility companies and operate them.
This shift in ownership marked a turning point. With The Geysers offering great potential, Calpine stepped in with much-needed upgrades –– funded by private capital, not ratepayer dollars.
Calpine brought an innovative approach to help restore the steam output needed to increase power generation. By partnering with neighboring municipalities, Calpine constructed pipelines to transport treated wastewater to The Geyers to replenish the reservoir and increase steam pressure.
After many upgrades to the power plants and adding new resources of water to help produce steam, The Geysers’ power generation has stabilized with a current net generating capacity of about 725 megawatts of electricity, supplying around-the-clock energy to Sonoma, Lake, and Mendocino counties, as well as parts of Marin and Napa.
Today, Calpine operates 13 geothermal power plants at The Geysers. The site remains the largest geothermal operation in the world and is now being celebrated for its 65th anniversary of supplying energy to California residents.
The Geysers demonstrate the power of competitive markets in action. Introducing competition into a state’s energy market allows for new investments and innovative ideas, without burdening otherwise captive ratepayers.
From its beginnings to its status today as the world’s largest geothermal facility, Calpine’s stewardship of The Geysers proves how competitive retail markets and independent generation investment can deliver lasting value for both consumers and their communities.
