A really small generator has been developed.
[quote[It may be tiny, but a new microgenerator developed at Georgia Tech can now produce enough power to run a small electronic device, like a cell phone, and may soon be able to power a laptop. The microgenerator is about 10 millimeters wide, or about the size of a dime. When coupled with a similarly sized gas-fueled microturbine (or jet) engine, the system, called a microengine, has the potential to deliver more energy and last 10 times longer than a conventional battery.[/quote]