Chena Hot Springs Resort installed the state of Alaska’s first geothermal energy plant in 2006. The project is notable for using innovative technology to produce geothermal energy at temperatures below the boiling point of water. It is also notable as a successful example of using geothermal energy to generate electricity on a small-scale commercial basis that can be replicated for community-based projects worldwide.
Traditionally produced geothermal energy is costlier and more time consuming since it relies on finding areas of the earth’s subsurface greater than 360 degrees Fahrenheit. Wells are drilled into these reservoirs to tap the hot liquids, called brine, and bring it to the surface to generate electricity.
Most of the geothermal reservoirs in the U.S. are located in western states, where they exist in shallow areas below the earth. The use of new technology expands the potential geographic area where geothermal power can be successfully employed. The new process, called binary technology, mixes geothermal hot liquids, or “brine,” with a fluid that has a lower boiling point than water. This allows a greater range of temperatures to be used to produce electricity. The secondary (binary) fluid, once combined with the first reservoir, passes through a heat exchanger where it is converted to vapor and used in the turbine generator for electricity.
The generators are produced by United Technologies Corporation (UTC) with assistance from state and federal agencies. When installed in 2006, the 400k W generators cost $2.1 million and displaced 150,000 gallons of diesel annually. After the success of these generators in 2006, the resort expanded its 400 kW of binary cycle generators to 680 kW in 2008.
In addition to the electric power plant, the Chena Resort now uses its geothermal resources for heating its outdoor baths, swimming pool swimming, and greenhouses. Geothermal resources also provides the energy for refrigeration for its outdoor ice museum.
Chena Hot Spring’s use of binary technology allows the community to address its off-grid energy needs and demonstrates how other communities may also reduce their reliance on diesel.
For more information, see: http://www.chenahotsprings.com/geothermal-power/