Blog Post

Insight: Geothermal Energy: Hot Rocks

By: Thomas Holst

The U.S. Department of Energy recently awarded a $140 million grant to the Energy and Geoscience Institute at the University of Utah for five years of R&D activity on two existing geothermal well sites near Milford in Beaver County. With this grant, Utah is poised to become the technology leader in geothermal energy derived from hot water and hot rock found a few miles beneath the Earth’s surface.

The United States is the world leader in installed geothermal energy, but experts estimate that less than a tenth of the known geothermal resources have been tapped in the U.S.  Like solar, geothermal energy can be scaled either to drive steam turbines to provide for electricity for an entire region or provide heating and cooling for individual residences and businesses.

Utah has the third largest installed geothermal capacity in the nation. Two utility-scale geothermal plants are operational in Utah. The Blundell plant in Beaver County, completed in 1984, is a 34-megawatt facility capable of providing electricity to 13,000 homes and businesses.  A 25-megawatt facility located in Cove Fort, Millard County combines geothermal with hydropower technology.

However, smaller-scale geothermal opportunities exist for individual homeowners and institutions such as schools, universities, and businesses.

Geothermal applications are typically divided into two water temperature ranges:

  1. Water temperatures less than 90° F may require heat pumps to deliver household services. In a heat pump, the geothermal water heats another fluid such as iso-pentane that is compressed and then channeled through household radiators.
  2. Water temperatures of 90° F to 340° F need no heat pumps and can be used for residential heating, greenhouse heating, radiant floor heating, and cooling and refrigeration.

Forty percent of all energy in the U.S. is used to heat and cool buildings. Geothermal is an excellent renewable energy for these needs. Proximity to thermal waters would be ideal, but not necessary, as illustrated in the case of the George Downey Mansion on South Temple Street in Salt Lake City.

Brothers Jon and Phil Lear purchased the Downey Mansion over a decade ago to house their energy law practice. Jon considered utilizing geothermal energy to avoid using natural gas, which had experienced steep price hikes after Hurricane Katrina in 2005.

Two heat sources for the Downey Mansion