Idaho’s Geothermal Resources
A Quick Overview of Idaho's Geothermal Program
Heat energy from the earth is considered a "green" source of energy because it is renewable and doesn’t emit carbon like the usage of fossil fuels. Over 200 springs and more than 1,000 wells producing naturally warmed waters are evidence of Idaho’s abundant renewable energy resources. These valuable resources are currently being used in Idaho for both Direct Use (the heating of public buildings, homes, and greenhouses, and the raising of fish and other aquatic species) and Power Generation.
Geothermal Resource Wells
Wells in Idaho with a bottom hole temperature of 212 degrees Fahrenheit or more are classified as a high temperature geothermal resource well. Idaho Department of Water Resources, under authority granted by the Idaho Geothermal Resources Act (Section 42-4001 through Section 42-4015, Idaho Code), regulates drilling, operation, maintenance, and abandonment (decommissioning) of all geothermal resource wells in the state.
Low Temperature Geothermal Resource Wells (LTG)
Wells in Idaho that have a bottom hole temperature more than 85 degrees F and less than 212 degrees F are designated as Low Temperature Geothermal (LTG) Wells. LTG wells are to be utilized primarily for heat value and secondarily for the value as water. Owners of an LTG well are required to file with the Department a bond ranging from five thousand to twenty thousand dollars, depending on the depth of the well. A well owner bond will remain in effect for one year following completion of the well. To drill and construct LTG wells, a drilling company must maintain with the Department a twenty thousand dollar bond.
Technical Reports and Interactive Map
Numerous technical reports and other publications for Idaho’s geothermal resources are available online:
Information Requests, Education, and Outreach
If you are unable to find the information you need on the previous websites, IDWR’s staff can help with questions about the occurrences and uses of, and opportunities for, geothermal resources in Idaho. Education and outreach events can also be scheduled for any size group. For more info, contact:
Ken Neely, Technical Hydrogeologist
Monitoring of geothermal resources is currently being conducted in four major areas: Boise Front, Twin Falls, Banbury, and Raft River. Monitoring data often include wellhead pressure and temperature, flow rates, and totalized flow. In the past, geochemical data were collected at many of the hot springs and wells. Monitoring data can be obtained by contacting:
Ken Neely, Technical Hydrogeologist
Management of Stressed Geothermal Aquifers
Declining wellhead pressures and water levels caused the IDWR to issue orders restricting additional geothermal withdrawals in the Boise Front and Twin Falls County areas. In the 1980’s, three geothermal Ground Water Management Areas were established as a result of these stresses: Boise Front Low Temperature Geothermal Resource Area, Twin Falls Geothermal Resources Area, and Banbury Hot Springs Area. Additional restrictions were put in place in the Boise Front and Twin Falls areas through Department-issued Moratoriums. Also, Ground Water District 63-S was established in 1989 for the Stewart Gulch area, which is a subset of the Boise Front GWMA, and is located about six miles to the northwest of downtown Boise.
Geothermal sources are typically much deeper than cold water aquifers used for domestic purposes and agricultural irrigation. Due to the pressure, temperature and depth of geothermal resources, wells drilled for the exploration and development of geothermal resources must meet more stringent construction standards than a typical domestic or irrigation well. Construction standards for geothermal resource wells require casing and sealing through the shallower ground water aquifers to prevent mixing that could impact the quality of potable water sources and damage the geothermal resource. Exploration and development of geothermal resources are regulated under the Idaho Geothermal Resources Act and IDAPA 37.03.04.
Drilling a geothermal well in Idaho requires a well construction permit. Specific regulations apply to the drilling of geothermal wells in order to protect both the geothermal resource and any overlying cold water resources. For more information, visit IDWR’s Well Construction page.
A water right is required to divert and use water in Idaho for all cases except for domestic use. Read more about Water Right information, including applications for new rights and water right transfers.
Raft River Geothermal Power Plant (courtesy US Geothermal Inc).