You won’t see a fuel-cell car by looking out the window. Only two models are available (the Toyota Mirai and the Hyundai Nexo). And only 15,000 fuel-cell vehicles purr along roads worldwide. Germany, for example, has just 500. But you may see one on TV, since the media has long touted fuel-cell cars as a promising alternative to plug-ins. In the mid-1990s, when many carmakers considered fuel cells the Next Big Thing, this gee-whiz attitude may have been justified. Since then, however, enthusiasm has waned. In September 2019 Volkswagen CEO Herbert Diess called BMW’s foray into fuel cells “nonsense.” Later that year USA Today pronounced the dream of a fuel-cell passenger vehicle “all but dead.” Are these assessments accurate?
A fuel-cell car is actually just another type of electric vehicle (EV). Unlike a plug-in EV, however, it generates its own electricity from hydrogen and stores it in a small onboard battery. This offers certain advantages. For one, fuel-cell cars have a smaller carbon footprint than today’s EVs. They can also refuel faster than EVs can recharge. Finally, fuel-cell vehicles currently have a slightly longer range.
The fuel cell’s silver lining, however, is darkened by some pretty big clouds. One is the disproportionately high cost of establishing fueling infrastructure. At the start of 2020, there were only 87 hydrogen fueling stations in Germany and just 134 in all of Europe. If the necessary infrastructure is built, Prof. Martin Doppelbauer of the Karlsruhe Institute of Technology points out that, due to hydrogen’s lower energy density, it would have to be “almost twice as large” as today’s natural gas infrastructure.
Also, a hydrogen car’s fuel cell and fuel tank are bulkier than an EV’s electric drive and batteries. This creates space problems. “Plug-in EVs offer about one class of vehicle more interior space than piston-engine cars of the same size, whereas fuel-cell vehicles offer one class less,” Doppelbauer says. This is unlikely to change much in the future because the difference is “largely due to hydrogen’s physical properties.”
But fuel-cell cars’ main drawback is their lower efficiency. All energy conversions – from falling water to electricity, from electricity to light – result in energy being lost. Fewer conversions therefore usually mean higher efficiency. Take the example of wind power and vehicles. An EV uses the electrical energy generated from the wind’s kinetic energy to turn its wheels. With a fuel-cell vehicle, by contrast, the wind power must first take a detour: it runs an electrolyzer that transforms water into hydrogen. The fuel cell then reconverts the hydrogen into electricity to power the car. This detour means that, given the same amount of wind power, a fuel-cell car travels one fifth to one third less distance than an EV. Doppelbauer calculates that for Germany to produce enough hydrogen to run all 47 million of its passenger vehicles it would have to produce about 50% more electricity than it does today – just to run the electrolyzers. For these reasons, Doppelbauer concludes that fuel-cell cars are “technical, economic, and environmental nonsense.”
Hydrogen has a bright future (but probably not in cars)
Fuel cells make much more sense for big vehicles that travel long distances, like in air, marine, and heavy-road transport. But hydrogen has a promising future in applications beyond mobility as well. For example, its qualities as an energy storage medium will make it essential for ensuring supply security and grid stability as the energy system transitions toward a high proportion of – and in some countries a complete reliance on – renewable energy. Hydrogen can also help decarbonize hard-to-abate industries like chemicals and steel. In short, hydrogen will play a much bigger role in a low-carbon future. If some is left over to fuel passenger cars, all the better.