The Utah School and Institutional Trust Lands Administration on Oct. 29 approved a request from the Director of the Utah Geological Survey (UGS) to drill two wells in Box Elder County to see if the state can drum up interest in geothermal power development in that area.
UGS had requested a right of entry to access trust lands in order to drill and monitor two geothermal temperature gradient wells in Box Elder County, which is just to the northwest of Salt Lake City and includes Great Salt Lake.
“Funding for this project is provided by the United States Geological Survey for the purpose of stimulating industry interest in geothermal development,” said a SITLA summary of actions taken on Oct. 29. “The U.S. Geological Survey – Western Research Drilling Program will drill the test wells using a rubber-tired truck mounted rotary drill rig. The wells will be drilled beside existing roads and will be drilled and constructed in accordance to Utah Division of Water Rights Rule R655-1-8, regulating the drilling of temperature gradient wells. The wells will be drilled to a depth of between 500 to 800 feet and will be monitored over a 10-year time span.”
The UGS website in a Sept. 27 entry said that the agency is looking toward new geothermal development opportunities in Utah. “Discovery of a new type of geothermal energy resource in Utah offers hope for significantly more potential across the western U.S., and a boost in geothermal power production. In 2011 and 2012, Utah Geological Survey (UGS) geoscientists, in partnership with a U.S. Geological Survey research drilling crew, drilled nine temperature gradient holes in Utah’s Black Rock Desert basin south of Delta to test a new concept that high temperature geothermal resources might exist beneath young sedimentary basins.”
Seven of the drill holes were funded by the U.S. Department of Energy as part of a National Geothermal Data System project, managed by the Arizona Geological Survey. The new holes also confirm the results from three other research holes that were drilled in the basin over the past few years, which were funded by the Utah State Energy Program and the Utah Division of Wildlife Resources.
Given the large area of this basin, the power potential is conservatively estimated to be hundreds of megawatts, and preliminary economic modeling suggests a cost of electricity of about 10 cents per kilowatt-hour over the life of a geothermal power project, UGS said. The modeling assumes air-cooled binary power generation with all produced water injected back to the reservoir so that there would be no emissions or consumption of water. The heat in the produced water would be exchanged at the surface in the power plant.
This basin is especially attractive for geothermal development because of the existing nearby infrastructure ─ it is next to a large coal-fired power plant, a 300 MWe wind farm, and a major electrical transmission line to California, UGS said.
Geothermal exploration in the Basin and Range Province of western Utah and Nevada has traditionally focused on narrow, hydrothermal upwelling zones along bounding faults of mountain ranges. However, basins within the Basin and Range usually have areas of many hundreds of square kilometers. “Although the depth to potential reservoirs beneath these basins is deeper than the geothermal industry is used to, the large reservoir area offers economies of scale,” UGS said. “Drilling to depths of 3-4 km is not unusual in oil and gas developments.”