Twenty years ago it appeared, for a moment, that all our energy problems could be solved. It was the announcement of cold fusion - nuclear energy like that which powers the sun - but at room temperature on a table top. It promised to be cheap, limitless and clean. Cold fusion would end our dependence on the Middle East and stop those greenhouse gases blamed for global warming. It would change everything. But then, just as quickly as it was announced, it was discredited. So thoroughly, that cold fusion became a catch phrase for junk science. Well, a funny thing happened on the way to oblivion - for many scientists today, cold fusion is hot again. We can yield the power of nuclear physics on a tabletop. The potential is unlimited. That is the most powerful energy source known to man," researcher Michael McKubre told 60 Minutes correspondent Scott Pelley. McKubre says he has seen that energy more than 50 times in cold fusion experiments he's doing at SRI International, a respected California lab that does extensive work for the government. McKubre is an electro-chemist who imagines, in 20 years, the creation of a clean nuclear battery. "For example, a laptop would come pre-charged with all of the energy that you would ever intend to use. You're now decoupled from your charger and the wall socket," he explained. The same would go for cars. "The potential is for an energy source that would run your car for three, four years, for example. And you'd take it in for service every four years and they'd give you a new power supply," McKubre told Pelley.