UTAH’S HIGH TEMPERATURE GEOTHERMAL RESOURCE POTENTIAL – ANALYSIS OF SELECTED SITES by Robert E. Blackett1, Glade M. Sowards2, and Edie Trimmer3 1Utah Geological Survey 2Utah Energy Office 3Utah Division of Forestry, Fire & State Lands July 2004 UTAH GEOLOGICAL SURVEY a division of UTAH DEPARTMENT OF NATURAL RESOURCES in cooperation with U.S. Department of Energy, National Renewable Energy Lab DISCLAIMER This open-file release makes information available to the public during the review and production period necessary for a formal UGS publication. It is in the review process and may not conform to UGS standards, therefore it may be premature for an individual or group to take action based on its content. Although this product represents the work of professional scientists, the Utah Department of Natural Resources, Utah Geological Survey, makes no warranty, express or implied, regarding its suitability for a particular use. The Utah Department of Natural Resources, Utah Geological Survey, shall not be liable under any circumstances for any direct, indirect, special, incidental, or consequential damages with respect to claims by users of this product. EXECUTIVE SUMMARY Geothermal sites in Utah, either suitable or potentially suitable for electric power generation, are limited in number given current economics and technology. For this study, we reviewed several hundred geothermal wells and springs in Utah, choosing nine geothermal areas or sites for more detailed review. Two of the areas – Roosevelt hot springs and Cove Fort- Sulphurdale - have been developed for geothermal power since the 1980s, and both will undergo expansion and power plant modification in the near future. Three other sites – Thermo hot springs, Newcastle, and Drum Mountains – experienced significant geothermal exploration in the past, but much more data are needed to fully evaluate them. The remaining four sites in northern Utah are virtually unexplored and were selected on the basis of geothermometry applied to geothermal water issuing at the sites. An overall comparative matrix of the study areas is presented in appendix D. The original intent of this effort was to rank the sites based upon an economic analysis of their electric power development potential. After entering this process, however, we realized that the required elements for such a ranking (reservoir temperature, depth, flow rates, and volume, among other factors), except in one case, are not known. As a result, for this analysis we classify these nine sites into three tiers based on levels of past exploration and industry interest noted above. Following are discussions of the sites themselves with respect to the classification scheme. First Tier – Resource undergoing active development, well defined. Roosevelt hot springs KGRA Cove Fort-Sulphurdale KGRA Second Tier – Resource explored, not defined. Newcastle Thermo hot springs Drum Mountains-Whirlwind Valley i Third Tier – Resource essentially not explored, indication of potential resource exists. Utah hot springs Ogden hot springs Hooper hot springs Crystal-Madsen hot springs First Tier Sites Roosevelt Hot Springs – Pacificorp (Utah Power) operates the single-flash Blundell plant (26 MW gross) with current plans to upgrade the plant by adding 13 MW reportedly from a “bottoming cycle” using binary power technology. Pacificorp’s recent Integrated Resource Plan identified portfolios containing significant upgrades to the Blundell plant, or building a nearby new plant; no new plant portfolio was selected, however. The geothermal field is controlled by a separate supplier entity – Intermountain Geothermal, a subsidiary of California Energy Company – maintaining the fluid supply to the Blundell plant through several production and injection wells. We are aware of no problems related to existing infrastructure and access that would encumber development. No environmental conflicts would appear to restrict future development, although the area is within mapped habitat for the Greater Sage Grouse, and may include several other listed species. Citizen groups propose part of the Mineral Range to the southeast as “wilderness” under some scenarios. Cove Fort-Sulphurdale – The Cove Fort-Sulphurdale geothermal field, controlled by Provo City, along with Utah Municipal Power Agency’s Bonnett geothermal plant (10 MW gross) was recently sold to private developers (Recurrent Resources). The new owners reportedly plan to decommission the old facility, consisting of a combination of flash and binary power plants, drill new production and injection wells, and construct a new 30 MW (gross) facility using binary technology. Surface land ownership is mixed, primarily USFS and private. No environmental conflicts would appear to restrict future development, although the area is within mapped habitat ii for the Greater Sage Grouse, a listed species. No wilderness areas are near here and none are recommended for future designation. Second Tier Sites Newcastle – The Newcastle area is undergoing active geothermal development for large-scale space heating of commercial greenhouses covering more than 10 ha (25 ac). This area was the recent focus of a U.S. Department of Energy-sponsored project to develop geothermal distributed power systems in the west. However, exploratory drilling in the outflow plume yielded temperatures less than required for commercial power generation. The suspected source-location of the geothermal fluids remains untested to date. Land ownership is mostly private within the current geothermal production area, although the suspected source location lies primarily on land administered by the BLM. No imminent environmental concerns have been identified. Present studies suggest a maximum resource temperature in a range around 130ºC (266ºF). Thermo Hot Springs II KGRA – The region surrounding Thermo hot springs has been of interest to prospective geothermal developers, although no developable resource is identified. Republic Geothermal and others drilled a number of exploratory boreholes and performed geophysical surveys in the area, measuring a maximum temperature of about 174ºC (345ºF) at a depth of about 2,000 m (6,600 ft). No environmental concerns are present that would outwardly restrict development, although the area is remote and contains several listed species including the Greater Sage Grouse. Drum Mountains Geothermal Prospect – Amax Geothermal and Phillips Petroleum Company explored the Drum Mountains-Whirlwind Valley area during the late 1970s and early 1980s. They identified no developable geothermal resource from this exploration, although they measured temperatures as high as 70ºC (158ºF) in shallow (generally 150 meters or less) boreholes. As a result, we include the area in our second tier classification even though a resource has yet to be discovered. The area is remote, and locally may contain only one listed species. A BLM wilderness study area (WSA) covers much of the Swasey Mountains directly southwest of Whirlwind Valley. iii Third Tier Sites Utah Hot Springs – The Utah hot springs site is one of three sites situated in the urbanized region along the Wasatch Front of northern Utah. We have identified this and the other two sites mainly on the basis of geothermometry, which suggests that the temperature of resource fluids at depth may exceed 190ºC (374ºF). Utah hot springs is within an urban-industrial setting adjacent to a utility corridor, highway, and Interstate 15. The springs were used for a time at a now- defunct resort, and are currently used to heat a small commercial greenhouse. Minor geothermal exploration was conducted in the early 1980s, but the resource is poorly defined. Although the area is industrial, large-scale development could be problematic due to the number of listed species (10) possibly in the area. Zoning restrictions may also impede development. Ogden Hot Springs -- This site is also within the urbanized Wasatch Front region. It was identified mainly on the basis of geothermometry, which suggests that the temperature of resource fluids at depth may exceed 190ºC (374ºF). Ogden hot springs is situated near the mouth of Ogden Canyon, near residential neighborhoods, utility lines, water sources, and roads. The springs have no history of extended use other than local recreation and bathing. Moreover, no geothermal exploration beyond surface spring sampling has been reported. Similar to Utah hot springs, large-scale development could be problematic due to the number of listed species (10) possibly in the area. Zoning restrictions may also complicate development. Hooper Hot Springs -- Hooper hot springs and Southwest Hooper warm springs are located about 16 km (10 mi) southwest of Ogden near the eastern shore of Great Salt Lake in an urbanizing portion of Davis County. Geothermometry suggests resource temperatures at depth near 135ºC (275ºF), although no exploration has been performed to date. The area is within a Utah Wildlife Refuge, which could be problematic for industrial development. This area also contains the largest number of listed species of all geothermal areas considered in this study. Land ownership is a mixture of Utah Sovereign Lands, Utah Wildlife Resources, and private. iv Crystal-Madsen Hot Springs – The Crystal-Madsen site is the northernmost of the geothermal areas studied. The area has been extensively developed as a resort, operating commercially at least for the past 75 years. The area is logistically attractive as there is ready access to roads and transmission lines. The resource is