Hydrogen as a fuel source for cars, etc.

Hydrogen
The great debate over hydrogen is far from over, although the fortunes of this energy source — where electricity is culled from hydrogen and oxygen — may depend on its larger adoption outside the automotive industry. If hydrogen cells become a storage solution for the energy produced by solar panels and wind turbines, then a hydrogen economy could appear in the coming decades, complete with a specialized distribution infrastructure (since the hydrogen must be stored under high pressure), as well as an increase in filling stations.

Best for: Hydrogen vehicles. These are similar to gasoline-powered vehicles in terms of range and performance, so their biggest selling point is their lack of emissions — the only waste product of the fuel cell's chemical reaction is water vapor. For the foreseeable future, though, the high price of hydrogen vehicles makes them attractive primarily to wealthy early adopters and municipal authorities hoping to reduce their emissions and overall carbon footprint. Even more experimental than fuel-cell vehicles is the prospect of blending hydrogen with natural gas, essentially a last-ditch effort that would negate much of the environmental advantage of using hydrogen, but could reduce the demand for foreign oil.

Where to fill up: For now, there are 65 hydrogen filling stations in the U.S. That number is expected to climb in the next few years, but not by much. With only a few hundred hydrogen vehicles on the road, the demand simply isn't there. The chances of finding hydrogen next to unleaded gasoline at your local filling station are low, and getting worse by the day. Unlike many other alternative fuels, hydrogen is seen as an all-or-nothing energy source. It requires an incredibly specialized distribution infrastructure that is unable to piggyback on the existing petroleum network — the delivery trucks are different, and so are the pipelines — and appears viable only as part of a national transition to renewable power sources. In other words, if hydrogen moves out of the pilot stage and into a filling station near you, it won't be sharing real estate with petroleum-based fuels. It would replace them.