Don’t Forget Geothermal: San Luis Obispo County Geothermal Resources

By Paul Gipe

Following the announcement of Pacifica Gas and Electric’s plans to close the Diablo Canyon nuclear plant, I circulated a postcard showing a vision of a post-nuclear future for the plant site.

The postcard depicted wind, solar, and wave energy at the plant site.

An astute reader asked, “What about geothermal?” Indeed, geothermal shouldn’t be overlooked.

While solar energy is available nearly everywhere, wind is very site specific. Geothermal resources are even more site specific than wind.

A quick search on Google turned up a 1983 study of the geothermal potential in the Paso Robles area of San Luis Obispo County.

This tells us two things. First, that California has been resting on its laurels since the early 1980s, regarding geothermal. Not much has been done since. Second, it tells us because of California’s complex and active geology there are more geothermal resources out there than most realize.

They found the reservoir covered 109 km² (42 mi²) with a temperature of 102-116 C (216-240 F) at a depth of 300 meters (1,000 feet).

Paso Robles became a settlement because of its hot springs that had long been used by travelers through the valley.