What do you think of an energy source that get's energy from temperature differences between warm surface water and cooler deep water, and which extracts fresh water from sea water as an added benefit if you like?
Never heard of it... it's real, it's OTEC, and local Hawaiian Engineering companies are working with Lockheed Martin to realize a 100MW power plant to put this energy source into action.
This energy is primarilly avaible in the tropics, though the energy could be converted to hydrogen or amonia (etc) as energy transport medium. As I said, it also produced fresh water. A common sense worry for an ardent environmentalist is the affect on the ocean temperatures, and this is an area of intense studies by the environmentally oriented researchers hoping this is one of a spectrum of clean energy sources which together can power the earth. Current models indicate that the energy available without temperature damage to the ocean is probably twice as much as current energy consumption of humans on planet earth (14 TW), and it seems quite assured that half the worlds energy could be provided via OTEC plants.
Another issue is that nutrient rich deep water is brought to the surface, and this must be mitigated to avoid plankton and algae blooms at the surface. Fortunately, the researches in this field are very concerned about such things. It is also fortunate to have fairly straight forward questions, question that do not involve asking where to put the inevitable toxic results of using or obtaining this power.
OTEC is a type of solar energy, using the ocean water as the storage reservoir for energy naturally collected by sea water.
* map of retrievable thermal energy: http://www.otecnews.org/...
* how it works: http://www.makai.com/...
* OTEC News: http://www.otecnews.org/