There's a problem with geothermal that no one mentions. Ie. heat only moves through the ground via conduction, not by convection or radiation. So once you pull the heat out of, say, the walls of a drilled shaft (thereby cooling them) it takes a long time for it to be replaced, since conduction is a very slow process. So there is a limit, set by conduction rates, to how much energy you can pull from a given "heat pump", no matter what you use the power for.
In reality geothermal energy is only viable on a large scale where there is geothermal activity (like Iceland, Alaska . . .). Even then, geo-heat is NOT an infinite source as people seem to think (funny how often people make that mistaken assumption). Need proof? Here are some geo-projects that extinguished popular fields of geysers around the world when they tapped their heat sources:
http://snras.blogspot.com/2008/10/geothermal-energy-development-geyser.html
At the same time, their power output has dropped steadily over the years.
Wind, 'bio-mass', ethanol and solar all have their potential pitfalls as well, if done badly. And "Clean coal" is a total misname; THERE IS NO SUCH THING! The term comes from those who stand to profit from it. Like when Eric the Red named a chuck of uninhabitable rock and ice "Greenland", "clean coal" advocates are trying to sell people a bill of goods. And how about ethanol; doesn't it seem odd to anyone that all the loudest deniers of ethanol's multiple problems as a fuel have profit motives?
My point is that all of the alternative-energy options need to be carefully considered *before* they are implemented, not built with a gold-rush mentality. Thus, while profits for innovators have to be part of the equation, they should NEVER, EVER trump sober consideration of possible down-sides. JC, Fairbanks, AK (Sent Thursday, January 29, 2009 10:38 PM
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