Dear EarthTalk: Not long ago we were reading a lot about hydrogen’s role in a clean energy future, with cars transitioning from gasoline-powered engines to hydrogen-powered fuel cells. Where does hydrogen fit now in the mix with electric cars now coming on so strong? — Amanda Jenkins, Troy, MI
It is true that just a few years ago everyone was talking hydrogen fuel cells as the future of petroleum-free automotive transport. Fuel cell cars can run on infinitely renewable hydrogen gas and emit no harmful tailpipe emissions whatsoever. A 2005 Scientific American article bullishly reported that car company executives “foresee no better option to the hydrogen fuel-cell vehicle in the long run.” Likewise, the International Energy Agency (IEA) suggested, also in 2005, that some 30 percent of the global stock of vehicles—700 million cars and trucks—could be powered by hydrogen fuel cells by 2050.
But high development costs and implementation hurdles have kept fuel cell vehicles (FCVs) out of the mainstream for now. And in the face of competition from a new crop of all-electric and hybrid-electric vehicles lately, some analysts wonder whether the fuel cell’s future is as bright as once thought. That’s not to say the technology isn’t impressive, and still potentially very promising. The concept was first developed by NASA some five decades ago for use in space travel and has since been implemented in a wide range of other mobile and stationary power applications. In an FCV, a stack of fuel cells under the hood converts hydrogen stored on-board with oxygen in the air to make electricity that propels the drive train. While automakers have been able to make fuel cells small enough to fit in and power a conventional size car or truck, the price per unit is high due to the need to incorporate expensive, cutting edge components. And the lack of widespread demand precludes cost-saving mass production. Also, the lack of hydrogen refueling stations around the country limits the practicality of driving a fuel cell vehicle.
According to Richard Gilbert, co-author of the book, Transport Revolutions: Moving People and Freight without Oil, another big issue for hydrogen-powered fuel cells is their energy inefficiency. Creating hydrogen gas by splitting water molecules via electrolysis ends up using up about half of the energy it creates. Another half of the resulting energy is taken up by the conversion of hydrogen back into electricity within fuel cells. “This means that only a quarter of the initially available energy reaches the electric motor,” reports Gilbert. (Making hydrogen by reforming natural gas is also highly inefficient and relies on a fossil fuel from the get-go.) Such losses in conversion don’t stack up well against, for instance, recharging an electric vehicle (EV) like the Nissan Leaf or Chevy Volt from a wall socket—especially if the electricity can be initially generated from a renewable source like wind or solar.
