Geothermal energy production has been studied extensively in Alaska. The proximity of Alaska to the Aleutian Subduction Zone makes it a prime location for geothermal activity. One hot spring location that has been studied extensively to see if they are viable options for geothermal energy generation is Chena Hot Springs, located approximately 30 miles east of Fairbanks.
In 2006, Chena Hot Springs Resort installed the first of two power plants to generate electricity for the resort. This was significant because the water that is heated at Chena Hot Springs is considerably cooler than most conventional geothermal systems. The water at Chena Hot Springs is between 165⁰ C, far cooler than the 200⁰ C that is usually required for conventional systems (Holdmann 2007). To get around this, the Chena system uses a refrigerant fluid, HFC134a, with a much lower boiling temperature than water (Holdmann 2007). This allows for the water in the system to turn the refrigerant to steam at a much lower temperature to spin the turbines.
Chena has lowered the cost of power at the resort to 5 cents per kWh with a 98% availability (Holdermann 2007). This allows the resort to primarily power their buildings via geothermal energy while using diesel generated power as a backup.