• Energy & Power

Under Our Feet: Geothermal Energy



The Earth houses a vast energy supply in the form of . Domestic are equivalent to a 30,000-year energy supply at our current rate for the United States! In fact, geothermal energy is used in all 50 U.S. states today. But geothermal energy has not reached its full potential as a clean, secure energy alternative because of issues with resources, technology, historically low natural gas prices, and public policies. These issues affect the economic competitiveness of geothermal energy.

Issues surrounding the adoption are divided into five main categories:

  1. Hydrothermal
  2. Deep Geothermal Systems
  3. Direct Use
  4. Geothermal (GHPs)
  5. and Co-Produced and Geopressured.

Geothermal resources are categorized in several layers of accessibility and feasibility, from broadest criteria (i.e., total physically available), to criteria that includes technical and economic considerations. The total resource base is scaled downward to accessible resource, and finally to a category called developable resource.

The table below shows estimates for the different geothermal resource categories, as compiled by the workshop experts. These estimates show the enormous potential of the U. S. geothermal energy resource. New low-temperature electric generation technology may greatly expand the geothermal resources that can be developed economically today.

Findings by Resource Category

Estimated Developable Resource*

Estimated Accessible Resource (MWe)

2006 (Actual MWe)

2015 (MWe)

2025 (MWe)

2050 (MWe)

Shallow Hydrothermal

(Identified) >90˚C/194˚F

30,000

2,800

10,000

20,000

30,000

Shallow Hydrothermal

(Unidentified) >150˚C/302˚F

120,000

TBD

TBD

TBD

Co-Produced & Geopressured

>100,000

23

10,000 to

15,000

70,000

>100,000

Deep Geothermal

1,300,000 to

13,000,000

0

1000

10,000

130,000

Thermal Uses

(MWt)

(MWt)

(MWt)

(MWt)

Direct Uses

>60,000

620

1600

4,200

45,000

Geothermal Heat Pumps

>1,000,000

7,385

18,400

66,400

>1,000,000

GHP Avoided Power

120,000

880

2,100

8,000

120,000

*These resource estimates represent a consensus of a group of experts who considered existing resource assessments (referenced on next page). There is considerable uncertainty in the estimates as many resources are hidden and exploration to date has been relatively limited. The figures shown above are not a resource assessment, but, even with uncertainty, clearly show that the U.S. geothermal resource is a very large and important domestic .