Environmental Law

U.S. Has Vast Untapped Geothermal Resources, Government Says

By Dennis Pfaff and Kevin Livingston, Editors

The United States has huge untapped geothermal reserves, which if developed could nearly triple the amount of power now coming from the renewable resource, according to a recently released government report.

Produced by the U.S. Geological Survey, the document estimated that the country's geothermal resources that could produce about 9,000 megawatts of power. Currently, about 2,500 MW are in production, meaning an additional 6,500 -- or 2.6 times what's in place now -- might be available. It is the first such report in more than 30 years.

Most of the current production is in California, according to industry figures. California also has nearly 60 percent of the total resource, the study said. But it identified about a dozen other states that also could produce power from the earth's heat. Currently, geothermal power is produced in six states. Nevada and Alaska rank behind California in terms of potential, according to the report.

In addition, the report estimated there were significant resources yet to be discovered from "conventional" sources.

An even greater potential exists for what is known as "enhanced" geothermal systems, which are created by fracturing underground rock layers and injecting water into them. According to the study, more than 517,000 MW, and -- and possibly more than 720,000 MW -- of potential electric power might exist in formations that could be exploited that way. Those figures add up to half or more of all the power generating capacity in the country right now, the study said. Even a low-range estimate of about 345,000 MW is more than the entire increase in generating capacity the country will need over the next 20 years, according to a set of graphics accompanying the report.

A statement accompanying the new report called geothermal energy an important but underutilized source of power. Despite that, by 2005, it accounted for about one-quarter of all the renewable power generation in the country outside of hydropower. In the statement, U.S. Interior Secretary Dirk Kempthorne said the study pointed to a greater potential for geothermal power than previous assessments:

"Geothermal energy is not only a renewable resource but could significantly contribute to our domestic energy resource base."

However, the information released by the government also showed that previous estimates of more than 23,000 MW for the capacity of already identified sources was significantly higher than than the figure contained in the new report. An official of the survey who headed up the study told the Las Vegas Review-Journal that many of the systems in the earlier assessment were believed to be much bigger than they actually are.

The paper also reported that proposals are being made to construct transmission lines linking the geothermal fields in the northern part of the state to electricity consumers in the south. An executive of one company warned that if Nevada doesn't secure the resource for itself, California will try to get it.

Release of the report comes at a time when there appears to be renewed interest in exploiting geothermal resources domestically. There also have been moves to increase international cooperation concerning the resource and even private research money is flowing into technologies to develop geothermal energy in hard-to-tap locations, trends Climate Law Update has been following.

--Dennis Pfaff of Thelen LLP

Photo: Steamboat Hills geothermal plant, Nevada, courtesy of U.S. Department of Energy-National Renewable Energy Laboratory; Credit: Joel Renner

Full post as published by Climate Law Update on October 09, 2008 (boomark / email).