Oceans as solar panels (Score 1)

The earth is already largely covered with solar panels, in the form of the oceans. The oceans convert solar energy into thermal energy, which manifests itself as the temperature gradient between the warm surface waters and the very cold depths There have been proposals to tap this energy by pumping cold water up from the bottom of the ocean and using it in conjunction with warm water from the surface to drive a heat engine. In many parts of the world, this process would actually produce positive net energy. (see http://www.nrel.gov/otec/what.html). I think it has been estimated that several hundred power stations operating on this principle, located in the tropics, would produce enough power to meet current world needs (Sorry, can't remember where I saw this estimate, which may be already out of date). The environmental cost would be a drop in water temperatures of 2 to 3 degrees Farenheit over a large part of the ocean's surface, enough to cause fairly catastrophic climate change. I guess you can't make an omelette without breaking eggs.