GEOTHERMAL RESOURCES AND DEVELOPMENT IN UTAH

With few exceptions, the higher value geothermal areas in Utah occur either in the Basin and Range Province of western Utah or within the Transition Zone of central and southern Utah. In these regions, thermal springs and wells are usually along valleys near the margins of mountain blocks, often spatially related to range-bounding faults and fractured zones. The Sevier thermal area, or STA, refers to a region in southwestern Utah encompassing the Sevier, Black Rock, and Escalante Deserts where known or estimated reservoir temperatures for a number of geothermal systems exceed 100°C. At least three geothermal areas within the STA are known, high-temperature geothermal systems, where fluid temperatures exceed 150°C. These high-temperature systems include Roosevelt Hot Springs, the Cove Fort-Sulphurdale area, and Thermo Hot Springs. In northern Utah, thermal springs occur near the west flank of the Wasatch Mountains, an area called the Wasatch Front. Two thermal areas along Wasatch Front valleys may hold high-temperature resources. In eastern Utah, the most significant occurrence of geothermal water is from oil wells of the Ashley Valley oil field, which yield large volumes of nearly fresh water at temperatures between 43°C and 55°C as a byproduct of oil production. Recently, geothermal operators announced expansion or reconstruction plans for power plants at the Roosevelt Hot Springs and Cove Fort-Sulphurdale geothermal areas in Beaver County. Others have proposed exploration for geothermal power development in eastern Box Elder County. Expansion of large, geothermal-heated greenhouses continues at the Newcastle area in southwestern Iron County, and at the Crystal-Bluffdale area in southern Salt Lake County. Also at Bluffdale, the Utah Department of Corrections completed a geothermal heating system for a portion of the Utah State prison. A proposed project may use low-temperature geothermal water to provide space heat for a large public transit service center in Salt Lake City.