Santa Rosa using geothermal power

February 27, 2008

Santa Rosa (California, U.S.A.) taps into neighbouring geysers to generate 850 megawatts of power.

Outside of Santa Rosa are the Geysers, the world’s largest installation of underground steam reservoirs. At the Geysers, pipes send the steam from drilled wells to central collection facilities, where it is used to power 31 steam turbines. The system generates more than 850 megawatts of electricity, enough to power about 850,000 homes on the state of California grid.

Santa Rosa’s relationship with the Geysers dates to the 1920’s, when entrepreneurs installed enough steam piping and turbines to light the buildings of a nearby resort. By the 1990’s, however, as the plumes of steam thinned, it was clear that after many years of use, the famed steam fields were almost tapped out.

In 1998, the city approved a plan to replenish the Geysers. A $US 187 million municipal initiative funded the construction of a 1.2 metre (four foot wide), 66 kilometre (41 mile) long pipeline to route 12 million gallons of the city’s wastewater per day back to the steam fields. Since the pipeline’s inauguration in 2003, it has consistently boosted the Geyser’s electrical output by about 85 megawatts, replacing conventional processes that would have released 570 million pounds of carbon dioxide into the atmosphere every year.

Santa Rosa is now pumping 16 million gallons of wastewater a day to the Geysers steam fields, producing an additional 150 megawatts of clean, green technology per year.

Fossil-fuel based power is a major source of greenhouse gas emissions. Green power from renewable energy sources emit no or low greenhouse gas emissions and other pollutants. Green power can include electricity generated exclusively from renewable resources including wind, hydro-electric or solar power – or electricity produced from a combination of fossil and renewable resources. For more information on the generation and use of green power at the local level, please visit www.iclei.org/ccp.

Santa Rosa is one of 296 local governments in the U.S.A. that are currently Members of ICLEI – Local Governments for Sustainability. For more information on ICLEI and its activities in the U.S.A., please visit www.iclei.org/usa.

Source: “Case Study: Tapping Geysers for Watts”, How America’s Greenest Cities Got Green, Popular Science, February 2008.