1. What is Geothermal?
2. What are the Technologies & Applications?
3. What is Utah’s Geothermal Energy Potential? Does Utah Have Geothermal Projects?
4. What are the Benefits?
5. What are the Challenges to Geothermal Development?

1. What is Geothermal?
Geothermal Energy is heat (thermal) derived from the earth (geo). It is the thermal energy contained in the rock and fluid (that fills the fractures and pores within the rock) in the earth's crust. These resources can be classified as low temperature (less than 90°C or 194°F), moderate temperature (90°C - 150°C or 194 - 302°F), and high temperature (greater than 150°C or 302°F). The highest temperature resources are generally used for electric power generation. Low and moderate temperature resources can be used for two applications: direct use heat and ground-source heat pumps.

2. What are the Technologies & Applications?
Geothermal Electricity Production - Geothermal power plants use steam produced from reservoirs of hot water found two or more miles below the Earth's surface. There are three types of geothermal power plants: dry steam, flash steam, and binary cycle.

• Dry steam power plants draw from underground resources of steam, which is piped directly from underground wells to the power plant, where it is directed into a turbine/generator unit. The only dry steam plants in the country are at The Geysers in northern California.
• Flash steam power plants use geothermal reservoirs of water with temperatures greater than 360°F (182°C), which flows up through wells in the ground under its own pressure. As it flows upward, the pressure decreases and some of the hot water boils into steam. The steam is then separated from the water and used to power a turbine/generator. Any leftover water and condensed steam are injected back into the reservoir to replenish the resource for reuse.
• Binary cycle power plants operate on water at lower temperatures of about 225°—360°F (107°—182°C). These plants use the heat from the hot water to boil a working fluid, usually an organic compound with a low boiling point. The working fluid is vaporized in a heat exchanger and used to turn a turbine. The water is then injected back into the ground to be reheated.

Direct use involves using geothermal resource at temperatures between 38°C (100°F) to 149°C (300°F). A well is drilled and the hot water is brought up through the well, and a mechanical system—piping, a heat exchanger, and controls—to deliver the heat directly for the heating of buildings, industrial processes, greenhouses, aquaculture (growing of fish) and resorts. Geothermal hot water can be used for many applications that require heat. Its current uses include heating buildings (either individually or whole towns), raising plants in greenhouses, drying crops, heating water at fish farms, and several industrial processes, such as pasteurizing milk. With some applications, researchers are exploring ways to effectively use the geothermal fluid for generating electricity as well.

Ground-source heat pumps use the earth or groundwater as a heat source in winter and a heat sink in summer. Using resource temperatures of 4°C (40°F) to 38°C (100°F), the heat pump, a device which moves heat from one place to another, transfers heat from the soil to the house in winter and from the house to the soil in summer. Accurate data is not available on the current number of these systems; however, the rate of installation is thought to be between 10,000 and 40,000.

Find out about more about geothermal technologies from the National Renewable Energy Laboratory Geothermal Technologies Program.

Sources of information: National Renewable Energy Laboratory Geothermal

3. What is Utah’s Geothermal Energy Potential? Does Utah Have Geothermal Projects?

• View Utah’s State Assessment for Geothermal/Biofuels Potential.
• According to Western Resource Advocates’ Renewable Energy Atlas of the West, Utah’s Geothermal resource potential for electricity generation is approximately 1 million Megawatt-hours annually.
• As of 2006, Utah was producing 4,000 Megawatt-hours of electricity from Geothermal. According to the Geothermal Task Force Report from the Western Governor’s Association, geothermal has the potential to supply 15,000 MW of electricity to the Western states by the year 2015. At a production cost of 8 cents per kWh, 10,000 MW could be provided.

4. What are the Benefits?
Geothermal energy systems have varied benefits, depending on the technology and application:

• Anaerobic Digestion Systems can provide farmers and ranchers with a viable means for reducing waste streams and generating on-site energy and/or fuels.
• Geothermal projects can strengthen rural economies and in some cases provide additional income to farmers and ranchers.
• Biofuels can help reduce America's dependence on imported oil.
• Depending on the application and technology, Geothermal projects may reduce air and water pollution and reduces greenhouse gas emissions. Using Landfill Gas (LFG) helps to reduce odors and other hazards associated with LFG emissions, and it helps prevent methane from migrating into the atmosphere and contributing to local smog and global climate change. For more information on Landfill gas to Energy Projects, visit the USA EPA Landfill Methane Outreach Program.
• Reduced risks of destructive wildfires.
• Reduced consumption of landfill capacity.
• Air quality benefits due to reductions in open burning of agricultural and forest residues.
• Compared with coal, geothermal feedstocks have lower levels of sulfur or sulfur compounds; substitution of geothermal for coal in power plants can help reduce sulfur dioxide (SO2) emissions. Demonstration tests have shown that geothermal co-firing with coal can also lead to lower nitrogen oxide (NOx) emissions and reduction in carbon dioxide (CO2) emissions.ⁱ
• Anaerobic digestion and biogas production can reduce overall operating costs where costs are high for sewage, agricultural, or animal waste disposal, and the effluent has economic value.
• Geothermal energy production makes substantial contributions to reducing greenhouse gas emissions by shifting the proportion of carbon emissions associated with geothermal cycling away from more climate active forms, and by protecting forest geothermal from destructive wildfires.ⁱⁱ
• Clean-burning technologies for wood fireplaces and stoves can help minimize particulate matter and air pollutants. For more information on wood stoves, visit the Environmental Protection Agency.

5. What are the Challenges to Geothermal Development?

• Cost of obtaining the feedstock
• Quantity of feedstock
• Transmission and distribution limitations
• High upfront capital costs
• Appropriateness of application
• Limitations related to water constraints

 i Energy Information Association. Geothermal for Electricity Generation. http://www.eia.doe.gov/oiaf/analysispaper/Geothermal/

ii Geothermal Task Force Report – Western Governors’ Association. http://www.westgov.org/wga/initiatives/cdeac/Geothermal-summary.pdf