Fuel Cells and Water Use

Dear EarthTalk: Regarding all the hype about fuel-cell powered vehicles that will run on hydrogen produced from water: Where is all this water going to come from? It’s my understanding that there is a severe water shortage, or potentially so, worldwide.

—Stephen Cavaliere, Honolulu, HI

Some 400 million people around the world do indeed suffer from water shortages, but analysts say that the eagerly awaited conversion to a hydrogen-powered energy economy will not aggravate such problems.

Even though hydrogen itself is the most common chemical element on the planet, it does not exist in nature in its elemental form. To generate hydrogen, electrical charges break up water molecules into their component parts of oxygen and hydrogen in a process known as electrolysis. The separated hydrogen is then compressed into storage tanks from where it is later dispensed into fuel cells that, in turn, generate power when it is needed.

Robert Wichert, a mechanical engineer who serves as technical director for the U.S. Fuel Cell Council, says that while water is initially broken down during this process, it is later re-combined and released into the atmosphere as water vapor. “Using water in this way does not deplete the amount of water globally,” he says. “Instead it uses water at one spot and releases it back into the rain cycle at the point of use.”

“When one looks at the water requirements for the production of hydrogen via electrolysis, the numbers are very interesting,” says Skip Staats of the National Fuel Cell Education Program (NFCEP). Staats” analysis shows that generating the energy equivalent of a gallon of gasoline in hydrogen requires just 2.3 gallons of water—all of which gets recycled directly back into the Earth’s hydrological systems.

Meanwhile, refining petroleum to create a gallon of traditional gasoline requires 12 gallons of water—which then must be treated before it can be released back into the environment. So, in essence, creating hydrogen via electrolysis requires less water than creating gasoline, and it is also a much cleaner process.

Right now, however, 95 percent of the hydrogen being produced in the world is derived not from electrolysis using water but by re-forming fossil fuels such as natural gas and even gasoline. A handful of forward-thinking companies are coming to the rescue, though. The U.K.-based Hydrogen Solar Ltd., for one, is commercializing “nanotechnology” to generate hydrogen from tiny solar cells without burning any fossil fuels. The company currently operates a prototype hydrogen re-fueling station just outside of Las Vegas, Nevada. Other major players include Midwest Optoelectronics, GE Global Research and Avalence LLC, all of whom have received sizeable federal hydrogen research and development grants.