Reference: Energy and earthquakes, Bangkok Post, July 15, 2009
Your article on geothermal energy states that interest in this technology is driven by the Obama adminstration's support for renewable energy (Energy and earthquakes, Bangkok Post, July 15, 2009). The economically feasible rate of heat extraction in geothermal plants, given the high cost of drilling and the high cost of insurance against environmental damage, will greatly exceed the rate at which the site can be naturally re-heated and therfore these sites will eventually become functionally depleted. The total amount of energy that would be available worldwide with this technology is rather large and geothermal energy could theoretically provide all our energy needs for hundreds of years but it is not renewable. An exhaustible energy source, no matter how long the useful life, cannot be considered to be renewable. The issue is a deeply sensitive one mostly because it determines whether the geothermal industry can benefit from funds that have been earmarked by the US federal government for renewable energy development.