I've read some things about "the hydrogen economy" as a component of future energy solutions. Of course hydrogen is more of a storage medium than a primary source of energy, and current methods of producing hydrogen are not especially efficient, especially those that start with natural gas as the raw material. But water is H2O and there is a lot of it on Earth - can't we get hydrogen from water? Sure, the well-known method is called electrolysis of water, but it takes quite a lot of energy.
According to this Technology Review article, a new solar hydrogen generator could make producing hydrogen from water a lot more practical. Nanoptek in Maynard, Massachusetts has a new process based on a nano-engineered catalyst. The special molecular structure allows lower-energy visible light photons to drive the reaction that separates the hydrogen and oxygen in the water, making the whole process more efficient and potentially cost-competitive with methods based on natural gas. They use solar concentrators to increase the available energy on the small conversion devices. Different size collectors and hydrogen collection and storage systems could make the process scalable so that hydrogen could be produced close to where it is needed, as long as there is enough available sunlight.