What a pleasant surprise to read James Yearling's informative piece about geothermal energy (HCN, 2/18/08). As a volcanologist who spent much of his 32-year career researching geothermal resources for the U.S. Geological Survey, I'm used to seeing geothermal treated like the comedian Rodney Dangerfield ... getting no respect. This lack of respect is in spite of the fact that generating electricity with geothermal steam has been done ever since a clever Italian scientist succeeded in 1904. Today, several countries (for example, Costa Rica and El Salvador) generate up to 25 percent of their nation's electrical power from geothermal steam. Moreover, in these times of global warming and much concern about carbon footprints, it's comforting to know that electricity generated using geothermal steam releases almost no carbon dioxide to the atmosphere.

Geothermal energy can be developed in many more ways than producing electricity. For example, it's hard to drill a well in volcano-rich Iceland and not encounter warm water. Virtually every building in that country is heated by routing such water through radiators. Geothermal heat is also being increasingly developed to both heat and cool buildings by installing ground-source (also called geothermal) heat pumps. If using geothermal heat to cool a building sounds magical, you may want to read about this process and many other characteristics of geothermal resources in USGS Circular 1249, Geothermal Energy - Clean Power From the Earth's Heat. Search this title at Google, and you can download your own copy.

Wendell A. Duffield
Flagstaff, Arizona