I'll bet you didn't know that aluminum (the same stuff that keeps your soda in the shape of a can) has more than twice the energy density of gasoline. Combine powdered aluminum with water at high temperatures, and you'll get heat, hydrogen and aluminum oxide. In other words, you get enough clean car fuel to take you 1,500 miles per tank.
The alchemists at a company called Alchemy Research are trying to push this aluminum-water reaction (that they're calling "Alydro") as a new source of dirt cheap but totally clean and recyclable energy. The reaction itself is very well known, and it looks like this:
To get this to work, you need water to be superheated into 900-degree steam, but once you get it going, the reaction releases about 50% of its energy in the form of more heat. The rest of the energy gets turned into hydrogen to power the fuel cells in your car, with aluminum oxide left over as waste. It's not really "waste," though. Since you can later separate the aluminum from the oxygen with electricity, the aluminum fuel is essentially rechargeable. As far as cost goes, aluminum is slightly more expensive on paper (about $0.10 per km as opposed to $0.07 for gas at $3.80 per gallon), but on a single tank of the stuff you get a potential range of nearly 1,500 miles.
While Alydro looks to be shaping up rather well, there are certain practical considerations that make aluminum fuel tricky to manage. The biggest one is that refueling your vehicle involves adding more aluminum, more water, and then taking out all of the aluminum oxide waste for recycling. On the other hand, the benefits are significant, too: beyond the eco-friendliness and the massive range, aluminum is also very easy and safe to transport and store. Heck, you could stash a big pile of it in your backyard if you wanted to, which is a bit harder to do with gasoline.
At the moment, it's hard to see much in the way of near-future adoption for this Alydro tech, but it all depends on how seriously we want to take our environmental responsibility. If, as a society, we decide that giving up fossil fuels is in our best interest, Alydro (once all the kinks get worked out) may come closest to giving us that gasoline experience without all the nasty side-effects that come along with it.