EmAre Fuel Cells the Future?
Are Fuel Cells the Future?
Are Fuel Cells the Future?
Monday, August 16, 1999
Over the last couple months there's been a spate of articles in science magazines and newspapers about advances in fuel cell technology and the possibility that it will someday completely alter how the world is powered. In fact although there are still many technical hurdles to overcome, fuel cell technology seems the most likely successor to fossil fuels.
Think of a fuel cell as a battery that never loses its charge. Two electrodes are suspended in an electrolyte while oxygen is passed over one electrode and hydrogen over the other. The resulting chemical reaction produces electricity, with heat and water the only byproducts. As long as hydrogen and oxygen are supplied to the fuel cell, it will keep generating electricity.
The principle that powers fuel cells was demonstrated in 1839, but it wasn't until the 1960s that fuel cells finally found a use as power supplies for spacecraft. The problems standing in the way of having fuel cells in cars or homes are still large.
First, the electrolyte solution requires platinum as a catalyst which makes fuel cells extremely expensive to make. Recent research efforts have focused on finding ways to reduce the amount of platinum needed and in one case scientists were able to reduce the platinum needed by a factor of 30.
Second, getting hydrogen to the fuel cells is a bit of a challenge. Liquid hydrogen must be stored at temperatures just slightly above absolute zero which is impractical. Hydrogen can be made, however, from natural gas or even methanol though storage is a problem. According to fuel cell researcher A. John Appleby, storing the three kilograms of hydrogen necessary to give a small car a 500 kilometer range would require a volume the size of three or four cars. And of course with hydrogen there is always the risk of explosion if hydrogen gas accumulates.
Still despite the technical obstacles, researcher on fuel cells is increasing at a rapid rate. Both General Motors and DaimlerChrylser are working on prototypes of fuel cells that convert methanol to hydrogen. Such a system would likely achieve a 50 percent methanol-to-electricity efficiency compared to the 15 to 20 percent gasoline-to-electricity efficiency achieved by the automobile's combustion engine under real world conditions.
Of course beyond automobiles, fuel cell research is also concentrating on powering homes and businesses, and here the story is the same. Fuel cells can be built today that provide enough electricity to power a home, but they deliver electricity at a cost 4 to 5 times higher than gas-fired combustion turbines do. In addition commercial fuel cells have a life span only half that of the turbines.
On the other hand at least three companies have produced smaller 7 to 10 kilowatt fuel cells that have been installed in demonstration homes and the market for 40 to 50 kilowatt cells is estimated to be as high as $50 billion if the cost comes down enough. Larger cells in the 200-kilowatt range have also been installed in a few places -- one was recently installed at the police substation in New York City's Central Park, for example.
Fuel cells are unlikely to become widespread overnight, but over the next two or three decades they could provide plentiful, low cost, nonpolluting energy for much of the world.
Fuel cells could revolutionize U.S. power supply. Associated Press, April 1, 1999.
The electrochemical engine for vehicles. A. John Appleby, Scientific American, July 1999.
The power plant in your basement. Alan C. Lloyd, Scientific American, July 1999.
May 2, 2006