Geothermal Energy

Geothermal energy is power extracted from heat stored deep underground, used to generate electricity and heat and to run a variety of industrial, desalination and agricultural applications (http://en.wikipedia.org/wiki/Geothermal_power). Geothermal energy is cost effective, reliable, and renewable (there is a theoretically inexhaustible supply). Geothermal wells tend to release GHGs trapped deep underground but the amounts are much less than emissions from fossil fuels (Bertani and Thain 2002). Geothermal plants can inject waste water back into the ground, converting it into a form of carbon sequestration (see “Carbon Sequestration”). As a replacement for conventional fuels, geothermal has the potential to significantly reduce GHG emissions if widely deployed as a utilities-scale power supplier (Fridleifsson 2008). Geothermal has previously been geographically limited to areas near tectonic plate boundaries but recent technological advances are expanding the range and size of viable resources. The North Coast is home to a portion of the largest geothermal energy plant in world: The Geysers field (in Sonoma and Lake Counties), which claims to produce one-fourth of the “green” energy in the state (http://www.geysers.com/).  The practice of using underground heat for energy can also be applied at scale of the individual home or business (See “Geo-exchange”).

Citations:

Bertani, R. and I.Thain. 2002. Geothermal power generating plant CO2 survey. International Geothermal Association News 49: 1-3

Fridleifsson, I.B., B. R. Bertani, E. Huenges, J.W. Lund, A. Ragnarsson, and L. Ryback. 2008. The possible role and contribution of geothermal energy to the mitigation of climate change. Pages 59-80.