Don’t forget geothermal!

November 3, 2008

One form of renewable energy that has been often ignored by the candidates this election is geothermal.  The LATimes gives a good overview of this high potential energy source today.  This renewable process has been getting more press lately since the Dept. of the Interior announced last week it was opening 190 million acres of federal land to possible geothermal energy production.     

Basically, geothermal energy production taps into underground steam that is naturally superheated in the earth’s crust to power surface turbines that generate electricity.  Since heat from the earth’s center is, for all intents and purposes, unlimited, there is enormous potential energy to be derived from this process.  There are two main stumbling blocks:

First, the upfront cost is high since the drilling process to extract steam is very expensive, and second, the process is mostly limited to geologically active zones. 

However, geothermal electricity currently costs about 4 to 7 cents per kw hour, which makes it much cheaper than solar and competitive with wind.  Additionally, geothermal energy is much more reliable, as the earth’s heat does not disappear randomly, like the wind and sun’s rays.

Currently, California leads the nation with the most geothermal energy production, at 1,800 MW.  Nevada is the second largest producer, and has 45 new projects currently underway.  These two states are the leading developers because they sit on the geologically active region where the Pacific and North American plates meet. 

Proponents argue that a process called “enhanced geothermal systems” (EGS) will allow geothermal production to occur in even non-geologically active regions.  EGS basically pumps water into the earth’s crust, where it turns to steam, and is then pumped back up to the surface to power the turbines.  EGS is currently in very limited use throughout the world.  However, it seems before we spend billions of dollars trying to pump CO2 from dirty coal plants into the ground, maybe we should consider an even cleaner alternative process like EGS?

Photo credit.

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