Their geothermal visitor center has a number of interactive displays that are excellent for getting you up to speed on geothermal power. This is one of the cleanest renewable power sources that are available to us, and with new breakthroughs in technology enabling them to open up new locations for geothermal It could be the way of the future to tap a virtually unlimited supply of energy.
They do have tours of the geothermal complex sites where power is generated and requires reservations to attend. It’s only held a few times a year so you have to plan well in advance. But the geothermal visitor center itself is worth visiting you could drive up over the hills from the Napa Valley, it’s the beautiful drive.

Great visitors center with interesting exhibits.

Largest of its kind in California, Sonoma County power plant uses volcanic activity and steam to generate electricity. Watch my video.
When early settlers first stepped foot on the Mayacamas Mountains in Sonoma County, they described it as a gateway to Hell. In a way, they were right.What they were seeing were plumes of steam shooting from the ground, super-heated by the earth below. Today, that steam is put to work at the Geysers Calpine Power Plant–better known as just “The Geysers”–and it’s California’s largest geothermal electrical generation site. the steam turns giant turbine generators that create electricity day and night. They generate 750 megawatts. That’s enough to power the city of San Francisco.The company gives free tours every month, but before the buses and the power plants, this area was a vacation destination. Farison says the geysers were discovered by grizzly bear hunters in 1847. It was believed that the hot waters had healing powers, and that brought in hordes of tourists and eventually led to the construction of a grand hotel and resort. Geysers are super-heated water that shoot out of the earth, but steam is the only thing coming out of the Mayacamas Mountains. Deep below the mountains is a layer of cracked and broken rock which is heated by magma. When groundwater gets into the cracked rock, it turns into steam and escapes through what are known as fumaroles. In the 1920s, it was discovered that the steam could be turned into electricity. Early on, it was used to power the old Geyser Hotel. By the 1960s, large generation plants like the Geysers were built.Today, Calpine Power Company owns around 28 power plants that use the earth’s pressurized steam to turn giant electrical generators. Each generator can power about 40,000 homes. Some of the steam is made using treated wastewater from nearby cities that have nowhere to put store it. Calpine pumps that clean, treated water underground, and when it hits the hot rocks it turns into more steam.