First Geothermal Plant in Alaska Starts Power Production
August 23, 2006
Chena Hot Springs announced on August 10th the successful commissioning and startup of the first geothermal power plant in Alaska. The unique 200-kilowatt power plant also holds a record for producing power from the lowest temperature resource yet: a well producing 162.5 degree Fahrenheit water. That's scalding hot water, but far from boiling. To produce power from the well, the company teamed with DOE, United Technologies, and Carrier Corporation to fashion a binary power plant from commercial air-conditioning equipment, using the air conditioning compressor as a turbine. The system essentially runs in reverse: the geothermal heat vaporizes the refrigerant; the refrigerant vapor passes through the compressor, spinning it and a generator to produce power; and then a condenser removes heat and converts the vapor back into a liquid. To make the system more efficient, Chena Hot Springs pipes its cooling water in from a well at a higher elevation, allowing gravity to push the water through the power plant without a need to pump it. See Chena Hot Springs' announcement, power plant description, and technical paper on the power plant (PDF 220 KB). Download Adobe Reader.
Chena Hot Springs is a resort that makes the most of its renewable resources, using the same gravity-fed water to irrigate its greenhouse and gardens, and employing geothermal energy to heat its 46 buildings. The resort is built around geothermal hot springs, but the company also erected the Aurora Ice Hotel in January 2004 to showcase ice art. When that structure melted during record temperatures in July 2004, the resort built a new structure, the Aurora Ice Museum, and cooled it with an absorption chiller that draws on geothermal energy. The new structure, built in January 2005, survived more record-setting temperatures that summer while hosting 10,000 visitors. The absorption chiller won an award from the Geothermal Resources Council last year. See the Chena Hot Springs Web site.