At first glance, hydrogen-powered electric cars using fuel cells seem like the ideal solution to pollution woes and dependence on imported oil. They don't use combustion but rather an electro-chemical reaction whose only major byproduct is water. Fuel cells have been used for years to provide electricity in space, and hydrogen is the most abundant element in the universe.
Many automakers are testing working prototypes, mainly in fleets, including the Daimler-Benz F-Cell, Ford Focus FCV, Chevrolet Equinox Fuel-Cell Vehicle, Honda FCX Clarity, Hyundai Santa Fe FCEV, Toyota Highlander FCHV, and Volkswagen HyMotion. And the federal government has committed hundreds of millions of dollars to do research on fuel cells and hydrogen issues. But daunting technical and infrastructure challenges make it unlikely that fuel-cell cars will get beyond the prototype stage for decades to come.
Manufacturing costs are now about a hundred times that of an equivalent gasoline car, however, and reliability and life-span issues are still being addressed. Honda's FCX Clarity was the first fuel-cell vehicle to be leased to a handful of consumers, but a Honda spokesman told us they didn't expect to produce a mass-market fuel-cell vehicle for at least 20 years.
Pressing problems for this technology are the issues of where to get the hydrogen and how to get it to the vehicle. While hydrogen is abundant, it's almost always bound up in minerals, hydrocarbons, or water and needs to be extracted.
An alternative is taking electricity from a nonpolluting source like solar, wind, or hydropower and using it to split water into its hydrogen and oxygen components. The problem here is that it takes more electricity to make the hydrogen than the hydrogen generates in a fuel cell.
Another problem is that hydrogen gas carries very little energy per cubic foot. So it has to be stored on a car at very high pressures up to 10,000 psi. Storing it in liquid form seems impractical, as it takes too much energy to cool it, and the hydrogen evaporates. The government is working on other storage methods, but so far all have so far proven too heavy and too costly.
Building a hydrogen distribution network also faces a major chicken-and-egg problem. Without the ability to refill them, people won't buy the cars, and without masses of cars to service, businesses won't spend the billions of dollars it would take to build the infrastructure. California and New York state have plans to construct small networks of hydrogen filling stations, which will increase the range of the tiny fleet of fuel-cell cars undergoing tests there. Those stations have electric-powered reformers that electrolyze water to make hydrogen on-site. Similar initiatives have been proposed in Canada.
A simpler solution is to burn hydrogen in a regular internal combustion engine, as BMW has demonstrated with a hydrogen-powered 7 Series sedan.
A hydrogen-burning engine creates no carbon dioxide (CO2), is relatively inexpensive to produce, and doesn't need the ultra-pure hydrogen that a fuel cell demands. On the other hand, it still requires a hydrogen-fueling system and needs a catalytic converter to reduce NOx emissions, and the vehicle needs a space-robbing tank.
Even if hydrogen fuel is relatively expensive, it could be the best alternative for making pollution-free vehicles.
As of this writing, it looks like battery-based electricity is the emerging technology, prevailing over all other alternatives. Most of it is due to the ability to use existing infrastructure.