Geothermal Resource Definitions

The total resource base in the , both renewable and non-renewable, is very large, with an energy content of over 657,000 billion barrels of oil equivalent (BBOE), or nearly 50,000 times the annual current rate of national . Figure 1 shows graphically what the total resource base looks like, and in descending order, the values for the estimated accessible geothermal resource and estimated developable resource.

Energy are traditionally classified according to the degree of certainty and the economic feasibility of exploiting the particular resource. The U.S. Geological Survey (USGS) and the U.S. Department of Energy (DOE) have used such identifying for resource classification. Following are simple definitions of these classification terms:

  • U.S. Total Resource Base – Resource base is all of a given material in the Earth's crust, whether its existence is known or unknown and regardless of considerations.
  • Estimated Accessible Geothermal Resource – The accessible resource base for geothermal energy is that part of the resource base shallow enough to be reached by production drilling in the foreseeable future.
  • Estimated Developable Resource – This category is the subset of the accessible resource base that the workshop experts believe likely to be developed in future years.