California, United States [RenewableEnergyWorld.com] Six Atlas Copco turboexpanders have been installed in Enel Green Power’s Stillwater and Salt Wells geothermal power plants near Fallon, Nevada. The two innovative geothermal plants have a total gross installed capacity of 65 MW and will generate more than 400 million kWh of electricity a year.
The Atlas Copco expander generators were manufactured at Atlas Copco Mafi-Trench Company LLC production facility located in Santa Maria, California. The large radial inflow turbines are capable of producing up to 15 MW per unit.
The Stillwater and Salt Wells facilities utilize binary cycle technology that employs two fluids. The hot water is extracted from the geothermal well is used to heat and vaporize a working fluid (isobutane in the case of Saltwells and Stillwater) that is completely contained in a closed loop. The vaporized working fluid is expanded through the Atlas Copco turbines, which spin electric generators and produce electricity.
The hot water is returned below ground and the isobutane leaving the turbine is condensed into liquid, which is then pumped up to high pressure. The isobutane is re-heated and re-vaporized, expanded through the turbine, condensed into liquid, and re-pressurized, always remaining within the closed circuit, ensuring no emissions.
Construction began in 2007 on the power plants and Enel fully commissioned the plants in April 2009 with an inauguration ceremony.
“We are proud to be a part of this significant geothermal project and look forward to a continued partnership with Enel. This is one example of Atlas Copco’s commitment to expanding our renewable energy product portfolio with a commitment to clean energy.” said Dre’ Schmitz, president of Atlas Copco Gas and Process Division.