Magma Power – Geothermal for the People


(Heated by magma near the Earth’s surface, natural ‘fumaroles’ or steam vents, emit steam in a field near piping that carries hot steam from the source).

When we think of renewable energy we mostly think of power from the sky – solar and wind. The power sources that we are trying to phase out come from underground – coal, oil, fossil gas. However there is at least one other energy source that comes from underground that is relatively benign and counts toward achieving California’s renewable energy goals – geothermal.

We in Sonoma County are fortunate to have this resource so close to us. Geothermal power of the type generated at the Geysers cannot be done anywhere. What is required is that the heat source that is hot enough needs to be near enough to the surface, the right kind of porous rock formation is needed, and finally, adequate water supply is needed. If all of these stars line up, and it’s a rare thing when they do, you have the ability to produce electricity from the Earth’s heat.

Although it’s right in our backyard, in the Mayacamas Mountains, historically, we in Sonoma County pay for a miniscule percentage of the operation. However, with the arrival of Sonoma Clean Power, we now have an opportunity to select a power product where 100% of our dollar pays for geothermal production at the Geysers. Sonoma Clean Power is developing a special relationship with the operators of most of the Geysers, Calpine. Overall, Sonoma Clean Power’s energy mix in 2014 is about 15% geothermal. That is the ratio that you receive if you choose the basic service, “CleanStart,” which comes in at about 5% below PG&E’s electricity rate. However, SCP has created an optional product that is 100% Geysers geothermal power. That’s 100% renewable energy from a local source. It’s called “EverGreen” and no money goes to fracking or nukes or coal or any other source, only geothermal.

Many supported Sonoma Clean Power because they expected it would catalyze the development of new local renewable energy generation. Sonoma Clean Power’s purchase of Geysers power does help catalyze new renewable energy. Every megawatt of Geysers power enables the installation of 3 to 5 megawatts of intermittent power like solar and wind. Industry rules specify a ratio of “baseload” power to intermittent power in a given area to protect customers from blackouts. Geysers power is baseload, meaning it runs around the clock. As distributed solar installation increases in the county, this renewable baseload power will become even more important to the stability and resilience of our local grid. And as the EverGreen program grows, Sonoma Clean Power will purchase more power from The Geysers.

No energy source is perfect, including solar and wind, and neither is geothermal, but electricity has been produced commercially at the Geysers safely since the early 1960s and we an expect it to operate safely for many years to come. Relative to some other forms of utility scale (large) power production like coal and nuclear, the problems associated with geothermal power generation are manageable. Small quantities of gases other than steam are produced in the process, small earthquakes are induced near injection and production wells, although small quakes naturally occur frequently in the area due to the fact that the Geysers field is geologically active, and energy must be expended to pump water to recharge the aquifer. In each case, the problems associated with electrical production are well known and are managed within safe and environmentally sound limits.

If you have signed up to be an EverGreen customer or sign up before May 14th, you can join a special tour of the Geysers on May 17th and see where your power comes from.


(From left to right: Dick Dowd Board Member of Santa Rosa Board of Public Utilities and Climate Protection Campaign, Danielle Seperas and Bruce Carlsen, Calpine Corp at the Geysers’ Visitors Center in Middletown).

By Woody Hasting