Did you know that the direct use of geothermal energy can be used to raise alligators?
The direct use of geothermal energy can apply to almost any activity that requires heating (and cooling) for industrial, residential and agricultural purposes. The heat is transferred by hot ground water in the temperature range of 20-120°C (70-250°F) which is produced from shallow wells and then distributed through surface pipework. One very popular direct use application of geothermal energy is for bathing in natural hot springs. Spas all over the world use naturally produced hot water for recreational and therapeutic purposes. In Utah, the Crystal Hot Springs offers warm and mineral-rich baths which attracts numerous visitors throughout the year.
Another direct use application is space heating that may serve a single, stand-alone structure, or more commonly multiple buildings, which are linked by a pipeline that supplies hot water. For regions that are subject to cold winters, this is a cost effective means of heating without contributing to atmospheric pollution. District heating has been in use since the late 1890s when the city of Boise, Idaho started using geothermal energy to heat buildings. District heating is also popular in China, Iceland, France, Germany, Hungary and New Zealand. In the state of Utah, the prison at the Point of the Mountain uses district heating for 330,000 sq. ft. of prison space, saving thousands of dollars over conventional heating systems.
This type of geothermal energy is even used to heat greenhouses to grow plants. The Milgro complex in Newcastle, Utah is one of the largest producers of poinsettias and chrysanthemums in the USA; it uses geothermally heated greenhouses to grow its flowers. This type of energy is also used to heat ponds for aquaculture and fish farming. The warm springs near Grantsville, Utah are filled with warm, mineral-rich water that supports a variety of fish and are also an attraction for scuba-diving activities. Fish breeders in Idaho farm a range of species, including ones requiring geothermally heated ponds, which famously once included alligators!
Did you know how geothermal energy is utilized?
The three most common applications are heat pumps, direct use, and electricity generation. Geothermal heat pumps extract heat from the shallow subsurface for heating in the winter and reject the heat back into the ground in the summer for cooling. Heat pump systems are the fastest growing use of geothermal energy in the world. They can be installed in individual homes or large buildings. Gardner Hall at the University of Utah is one of several large buildings in Utah using heat pumps for heating and cooling. Heat pumps do not require a source of hot water, instead they use the natural thermal energy in the ground at less than 5 feet depth.
Where hot water occurs in the shallow subsurface at temperatures between 35° and 150°C (95-300°F), it can be used directly for bathing and spas, heating buildings, and for industrial purposes such as vegetable drying and raising fish. The poinsettias and chrysanthemums sold in grocery and garden stores are grown in a 24 acre geothermally heated greenhouse complex in Newcastle, Utah.
Geothermal power plants produce electricity from hot water with temperatures ranging from about 150° to 320°C (300 to 600°F). The lower temperatures can be found throughout the western USA; the highest temperatures are common around volcanoes, including those making up the Pacific Ring of Fire.
The hottest geothermal wells produce steam, which is used to spin turbines for electric generation. Where just hot water is produced, a heat exchanger is used to boil a secondary fluid to produce vapor that spins the turbine. Once the electricity is generated, the water is injected back into the hot subsurface reservoir where it is reheated. Recently, the University of Utah signed a contract with Cyrq Energy for 20 megawatts of geothermal electricity. This geothermal electricity will provide about one third of the University of Utah’s power requirements.
Did you know that Utah is No.3* in the United States for its production of geothermal energy?
The State of Utah is responsible for 2.8 % of the national geothermal power production. The United States leads the world in the amount of electricity generated with geothermal energy, producing about 16.7 billion kilowatthours (kWh), equal to 0.4% of total national electricity generation. Utah is one of the eight states that are producing geothermal energy, and currently has three geothermal electric plants. The three generation facilities are at Roosevelt Hot Springs by Utah Power and CalEnergy Corp., Thermo Hot Springs by Raser, and Cove Fort Station of Utah Municipal Power Association. While the state of Utah is now capable of generating 72 megawatts**, the Utah Governor’s Office of Energy believes it can increase geothermal power generation by another 2,200 megawatts hoping to bring more clean and renewable energy into the state’s power source.
*California leads the nation’s geothermal energy generation with a national share of 71.9 %, and Nevada follows second with 21.7%
**A megawatt can power between 750 and 1,000 homes