Researchers have devised a way to turn heat into electricity
 

http://www.eetimes.com/rss/showArtic...etimes_newsRSS

I guess that keeping the gasoline engine in hybrids running will become much more important int he future, as hybrid automobile manufacturers try to minimize the amount of heat wasted by trying to turn every last joule into electricity without lowering the engine's minimum operating temperature. This could potentially either replace the radiator or allow radiators to become smaller.