There are many obstacles to creating an energy future reliant on hydrogen, but it is a mistake to think the hydrogen future must include fuel cells. In our posts critical of the hydrogen lobby we have oversimplified that point, because hydrogen can be used as fuel for an internal combustion engine. And even when hydrogen combusts, it is still absolutely pollution free, emitting only water vapor.
When we participated in California’s hydrogen highway planning sessions a few years ago, there was an obvious disconnect between what the hydrogen zealots wanted, and what the industry engineers claimed was feasible. I distinctly remember representatives from Ford and Toyota patiently trying to explain how easy it would be to just convert a vehicle to run on hydrogen – keeping the internal combustion engine.
Today a BBC report entitled “BMW’s Hydrogen Car” describes the experience writer Jorn Madslien has as he tools along the autobahn north of Berlin in a prototype that delivers over 300 horsepower. By sticking with an internal combustion engine, BMW is bucking the trend, and will undoubtedly deliver affordable hydrogen-powered cars way, way ahead of the pack. Designing vehicles with onboard fuel cells is still very problematic, and not just because of their expensive raw materials.
None of this means the hydrogen future is going to be easy, or will ever occupy more than a niche in tomorrow’s energy economy. We like hydrogen because it can be produced using nothing more than electricity and water, and you can burn it with no pollution. We believe that technology is about to deliver a photovoltaic revolution, so being able to produce vast quantities of “green” hydrogen is not a far fetched notion. But storage and distribution of hydrogen remains an extremely challenging obstacle.
On board BMW’s hydrogen car, for example, is a tank of liquified hydrogen. This requires a refrigeration system, as well as the necessity to bleed off a small percentage of the liquified hydrogen as gas each hour. Absent a recapturing device, this means such a vehicle could never be parked in an enclosed environment such as a parking garage, since the hydrogen gas would collect and could cause a catastrophic explosion.
On a larger scale, hydrogen storage is even more problematic. At any given moment, there are well over 400 million barrels of gasoline (a five day supply) refined and working through the worldwide storage and distribution infrastructure. How on earth are we going to store that much energy in the form of hydrogen? In practical terms, this would require ultra-cold liquification, or containment in 10,000 PSI pressure vessels. By contrast, natural gas only requires pressure vessels at 300 PSI. Storing hydrogen would require a containment vessel literally 30 times as strong as natural gas. Gasoline, of course, simply requires a tank.
So if you take away the fuel cell and go with internal combustion, and if you assume we are on the verge of having abundant electricity via photovoltaics, then hydrogen looks a lot better. But because of the remaining storage and distribution challenges, replacing petroleum with hydrogen is going to take creativity, technological breakthroughs, and an investment in infrastructure we can scarcely imagine. My money is still on batteries.