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  • Writer's picturePacific Sun Technologies

California needs clean energy after sundown. Is the answer under our feet?

After years of playing third fiddle to solar and wind power, new geothermal plants are finally getting built.


After years of playing third fiddle to solar and wind power, geothermal energy is poised to start growing again in California.

Three local energy providers have signed contracts this month for electricity from new geothermal power plants, one in Imperial County near the Salton Sea and the other in Mono County along the Eastern Sierra. The new plants will be the first geothermal facilities built in California in nearly a decade — potentially marking a long-awaited turning point for a technology that could play a critical role in the state's transition to cleaner energy sources.

Geothermal plants can generate emissions-free, renewable electricity around the clock, unlike solar panels or wind turbines. The technology has been used commercially for decades and involves tapping naturally heated underground reservoirs to create steam and turn turbines.

Despite those advantages, development has been bogged down by high costs. Building a geothermal facility can be several times more expensive than a comparably sized solar or wind farm, meaning geothermal plant operators must charge more for the electricity they generate.

Geothermal accounted for 4.5% of California's electricity mix in 2018 — about one-fifth the amount supplied by solar and wind, which made up the bulk of California's renewable energy supply.

Now those dynamics may be starting to shift.

State lawmakers passed a bill in 2018 mandating 100% climate-friendly electricity by 2045. As energy providers forecast their supply needs in a not-too-distant future without fossil fuels, some have decided it makes sense to start adding geothermal to the mix.

“At the face of it, geothermal tends to be more expensive than other resources, especially solar. But you have to really look at the value proposition, not just the cost," Monica Padilla, director of power resources for Silicon Valley Clean Energy, told the agency's board of directors this month.

Silicon Valley Clean Energy teamed up with another local electricity provider, Monterey Bay Community Power, to negotiate a contract with Ormat Technologies of Reno for 14 megawatts of power from a geothermal plant the company plans to build in Mono County.

The rest of the facility's capacity is already under contract to Colton, a city in San Bernardino County, under a deal signed last year. It's due to come on line in 2021, nine years after the state's last geothermal plant opened.