USA - Direct Uses




individual space heating



Distric heating



Air conditioning



Greenhouse heating



fish farming



Agricultural drying



Industrial process



Snow melting



bathing and swimming



 geothermal heat pumps





Total thermal installed capacity in MWt


Direct use in TJ/year


Direct use in GWh/year


Capacity factor



Country Update: Geothermal energy is used for both electric power generation and direct utilization in the country. The direct utilization of geothermal energy includes the heating of pools and spas, greenhouses and aquaculture facilities, space and district heating, snow melting, agricultural drying, industrial applications and ground-source heat pumps. The largest application is ground-source heat pumps accounting for 88% of the annual energy use, with the next largest application being fish farming and swimming pool heating. Direct utilization (without heat pumps) has remained nearly static over the past five years with gains balancing loses; however, ground-source heat pumps are being installed at a 8% annual growth rate with 1.4 million units (12 kW size) in operation. A total of two new projects have come on line in the past five years; the addition to Boise State University to the city district heating system adding 60,000 m2 of floor area; and a district heating system in Lakeview, Oregon connecting five schools, the local hospital and health care facility. In summary, when considering direct-use without geothermal heat pumps, the distribution of annual energy use is as follows: 34% for fish farming, 28% for bathing and swimming, 15% of individual space heating, 9% for greenhouse heating, 9% for district heating, 3% for agricultural drying, 2% for industrial process heating, <1% for cooling, and <1% for snow melting. The installation of new ground-source heat pumps are 60% in commercial and institutional buildings, and 40% in residential locations. Approximately 90% of the units are closed loop (ground-coupled) and the remaining open loop (water-source). Within the residential section, of the closed loops systems, approximately 30% are vertical and 70% horizontal, as the latter are cheaper to install. In the institutional and commercial section, 90% are vertical and only 10% horizontal, constrained by ground space in urban area.

Taken from: John W. Lund and Tonya L. Boyd
Published in Direct Utilization of Geothermal Energy 2015 Worldwide Review

Total thermal installed capacity in MWt:12,611.46
Direct use in TJ/year56,551.8
Direct use in GWh/year15,710.1
Capacity factor0.14

Most of the direct use applications have remained fairly constant over the past five years; however, geothermal heat pumps have increased significantly. A total of 20 new projects have come on-line in the past five years and a number of projects have closed.

Agricultural drying has decreased the most due to the closing of the onion/garlic dehydration plant at Empire, Nevada. Two district heating projects have also shut down; the Litchfield Correctional Facility in California and the New Mexico State University system.

There has been a slight increase in snow melting, cooling and fish farming, with a major increase in industrial process heating due to two biodiesel plants (Oregon and Nevada), a brewery (Oregon), and a laundry (California) coming on line.

The number of installed geothermal heat pumps has steadily increased over the past 15 years with an estimated 100,000 to 120,000 equivalent 12 kWt units installed this past year. Present estimates are that there are at least one million units installed, mainly in the Midwestern and eastern states. Over 50% were installed in 10 states (Florida, Illinois, Indiana, Iowa, Michigan, Minnesota, Nebraska, New York, Ohio and Pennsylvania) (EIA, 2008). Approximately 70% of the units are installed in residences and the remaining 30% in commercial and institutional buildings. Approximately 90% of the units are closed loop (ground-coupled) and the remaining open loop (water-source). It is presently a US$2 to US$3 billion annual industry in the country. The largest installation currently under construction is for Ball State University, Indiana where 4,100 vertical loops are being installed to heat and cool over 40 buildings using geothermal heat pumps.

The distribution of the various applications are as follows:

139.89 MWt and 1,360.6 TJ/yr for individual space heating;
75.10 MWt and 7,73.2 TJ/yr for district heating;
2.31 MWt and 47.6 TJ/yr for air conditioning (cooling);
96.91 MWt and 799.8 TJ/yr for greenhouse heating;
141.95 MWt and 3,074.0 TJ/yr for fish farming;
22.41 MWt and 292.0 TJ/yr for agricultural drying;
7.43 MWt and 227.1 TJ/yr for industrial processing;
2.53 MWt and 20.0 TJ/yr for snow melting;
112.93 MWt and 2,557.5 TJ/yr for bathing and swimming;
12,000 MWt and 47,400 TJ/yr for geothermal heat pumps.

The total is 12,611.46 MWt and 56,551.8 TJ/yr 

Taken from the paper by John W. Lund, Derek H. Freeston, and Tonya L. Boyd: "Direct Utilization of Geothermal Energy 2010 Worldwide Review"; published in Proceedings of the World Geothermal Congress 2010, Bali, Indonesia, 25-29 April 2010