But to the average listener, Bush’s words sounded reasonable. The exhaust from a hydrogen engine is just plain water—unlike the noxious mixture of greenhouse gases, acid rain-causing compounds, and uncombusted gasoline that normal engines emit. And supporters hope that increased usage of hydrogen would alleviate our dependence on foreign oil, if we aren’t fuelling up with Saudi gas. This is the popular allure of hydrogen fuel: cleaner than Dick Cheney’s dinner plate, and not beholden to unstable and perhaps unfriendly governments.
So as our supplies of petroleum become scarcer and more costly, the notion of hydrogen-powered cars becomes more appealing. Hydrogen provides a tremendous boom for its bang: burning hydrogen releases more energy per pound of fuel than any other material on earth. Spurred by the key invention of the fuel cell, which allows for a controlled consumption instead of a rocket-launching burn, automobile manufacturers have developed concepts for hydrogen-powered cars, touting their vehicles as the future of transportation. Last week, for instance, General Motors announced that it will place 100 hydrogen-fueled cars on the road next year, with the hope of increasing that number to 1,000 by 2010.
But amidst the hydrogen hype, few have noted where the new fuel comes from: fossil fuels. As it stands, burning hydrogen reduces neither demand for fossil fuels nor emissions of carbon dioxide, because almost all the hydrogen used today comes from natural gas.
The most common technique for producing hydrogen is known steam reformation. In this process, natural gas is heated with water at high pressures, yielding hydrogen gas and carbon monoxide, which is converted to carbon dioxide in the atmosphere. Thus, because carbon dioxide is a waste product, hydrogen cars recreate the same problem that they are advertised to sidestep: greenhouse gas emissions, which the balance of scientific evidence suggests lead to global warming. More environmentally friendly methods of generating hydrogen, such as coaxing bacteria to turn water alone into hydrogen, are still largely in the exploratory phase.
There are also a host of technological hurdles stand between our current capabilities and a highway full of hydrogen vehicles. Distributing hydrogen to consumers will require an entirely new infrastructure to transport the gas as well as new filling stations. Safely holding hydrogen in cars will require heavily reinforced tanks to prevent the family station wagon from going the way of the Hindenburg. And although hydrogen has a high energy yield per pound, it has an incredibly low mass density, even at subzero temperatures, so fuel tanks need to be unreasonably large to give hydrogen vehicles usable driving ranges. Still, scientists hope that these challenges can be solved with new—albeit potentially expensive—technologies.
The real problem is that politicians and automobile manufacturers (and, in turn, the public) tend to conflate two separate problems: finding a safe, steady supply of energy, and finding away to store that energy in a car. Gasoline easily solves the latter problem because it is so easy to transport compared to, say, a lighter-than-air gas like hydrogen. Hydrogen, which is at best a troublesome way to store energy, is being touted as an energy source when the actual source of hydrogen is a fossil fuel. In the end, hydrogen is just a convenient way for handling the energy originally stored in natural gas—except that, given current technology and infrastructure, it’s not so convenient at all.
The challenge, then, for creating cars that run on something other than oil—and, further down the road, generating the bulk of our electricity from something other than coal—is two-fold. We need a renewable energy source that doesn’t emit greenhouse gases. And we need a way of storing that energy in a form that can be driven around. The latter has few viable solutions: despite intense research, battery technology is still relatively poor, and hydrogen has all the disadvantages already discussed. For the former, we have lots of promising, but highly underdeveloped, ideas, from massive oceanic windmill farms to gasoline-oozing bioengineered algae to corn-derived ethanol (which itself presents a host of under-explained technological challenges and deleterious environmental impacts).
So long as promises of magical hydrogen-derived energy obscure the real challenge—finding an energy source, not just a storage system—then politicians and the public will continue to delude themselves into thinking that the quest for a new energy source is well on its way, rather than in the stage of infancy.
Matthew S. Meisel ’07, a Crimson editorial chair, is a chemistry concentrator in Currier House.