NEVADA GEOTHERMAL RESOURCES - 2007 UPDATE

At least 40% of Nevada has potential for high-temperature geothermal resources and much of the rest of the state has potential for low- or moderate-temperature resources. Nearly all of Nevada's resources are related to deep circulation of fluid in an area of crustal extension and high heat flow. Electric power is generated from resources at nine geothermal systems in northern and northwestern Nevada, and several other areas are slated for power plants in the next few years. After remaining relatively flat for 12 years, Nevada's installed geothermal electric nameplate capacity increased 14% in 2005 and 8% in 2006 to 297 MW. Nevada produced about 1,333 GWh of electric power to the grid from geothermal energy in 2006. Two new power plants (50 MW total) came on line in late 2005 and 2006. Production temperatures range from only slightly above boiling (107ºC) for a small (1.2 MW) plant, to 143-174ºC for most plants. Production depths range from a few hundred to over 2000 m. The average production capability of individual wells ranges from 1-6 MW. Leasing activity on federal lands has considerably expanded over the last two years. The U.S. Bureau of Land Management issued leases for over 130,000 acres at more than 25 separate areas in the first eight months of 2005. Nevada's non-electric uses include onion dehydration, space heating, and spas. One dehydration facility, and several aquiculture and space-heating applications have been discontinued over the past 10 years for reasons unrelated to the resources. Modern exploration for geothermal resources began in the 1960s with drilling at active hot springs; today, there is more focus on the search for concealed systems. Detailed studies of several systems previously considered concealed have revealed subtle surface indications of past or present geothermal activity. Faults and associated fractured rock form the reservoirs at most Nevada geothermal systems. Although porous Quaternary sediments make up the reservoirs at three fields, those fields are spatially associated with Quaternary active faults.