. >> reporter: michl binderbauer is chief technology officer for a startup called tri alpha energy, thatmaking a $500 million bet on fusion. >> think of this like a mini- sun, a very hot mini-sun, and it radiates, and it's that radiation that is intercepted on the surface of the machine, and then it becomes heat, and then you can process that into electricity. >> reporter: the promise: no less than limitless power, with virtually no greenhouse gases or radioactive waste. if that sounds too good to be true... it is. no one knows that better than nuclear engineer steve dean. >> fusion is not low tech. it's not going to be easy to prove that it's reliable, maintainable and cost-effective, because it is complicated. >> reporter: dean is president of fusion power associates, a foundation focused on research and education. he joined the fusion industry in 1962, working for the u.s. atomic energy commission, which coordinated and funded the u.s. fusion effort. >> for me, it seemed like it was something i could spend my career on and we would have electricity on the grid by the time i retired. t