That's the wildcard though isn't it? Some, such as yourself, decry this form of futurism because it is predicated on the assumption that energy will become more expensive. I personally think it will become cheaper and personally am open to the possibility of breakthroughs making it negligibly cheap. See http://www.bloomenergy.com/products/, http://ecat.com. E-cat may or may not be real, but I do see interesting possibilities as a lot more time and research starts to be put into these sorts of technologies as conventional fuel becomes more expensive.