The elusive dream of producing clean, inexhaustible fuel to run everything from our cars to our cell phones may not be quite as illusive as we had thought. Scientists around the world are making significant progress toward using sunlight to split water into hydrogen and oxygen.
The goal is alluring because a cheap way to extract hydrogen from water would end energy shortages around the world while cleaning up the environment using two of nature's gifts, water and sunlight.
Sound too good to be true? Maybe it is, because the challenges are still great, but there are several reasons to be optimistic. Within the past few days, several research teams have reported progress toward reducing the cost of hydrogen production, currently a show stopper.
Meanwhile, other teams are having some success in creating new materials that can trap and hold those tiny hydrogen atoms until they are ready to be used.
The competition is intense, for obvious reasons. We are still in the age of hydrocarbon fuels, because they have been easy to acquire and amazingly efficient in terms of the amount of potential energy in a given volume. It takes a lot of hydrogen to produce the same amount of useable energy as a gallon of gasoline, which, incidentally, has become extremely tough competition. But clearly oil is not inexhaustible, and those countries that have it can hold the rest of the world hostage. Something has to change.
Here are a few givens if hydrogen is to succeed. The cost of producing it must be slashed. More efficient ways to harness solar energy must be found, because sunlight is a critical component in any feasible large-scale method of splitting water. Hydrogen, like any other fuel, has safety risks that must be overcome.
Hydrogen Fuel Could Reduce Dependence on Oil, Fight Global Warning
Yet hydrogen is being "aggressively explored" as a fuel for passenger cars, according to the Department of Energy, partly because it "has the potential to dramatically reduce our dependence on imported oil." It also could help in the fight against global warming because no greenhouse gases would need to be released into the atmosphere.
DOE is funding much of the research in this country, and it has set goals that some had thought could not be reached. Eight research institutions are trying to meet DOE's target of bringing the cost of hydrogen production down to $6 per kilogram (2.2 pounds) by 2015 and $2-$3 per kilogram by 2025. So far, only one team has reached those goals, the University of Colorado at Boulder.
The Boulder team built an array of mirrors to concentrate the sun's rays and generate temperatures as high as 2,640 degrees Fahrenheit. That heat, directed on a thin film of metal ferrite created by the Boulder team, splits water at 482 degrees cooler than other technologies.
In announcing the development, Alan Weimer of Boulder's chemical and biological engineering department, said the lower temperature makes water-splitting more cost effective and faster.
"It's pretty significant and it seems like there's a good shot for this to become mainstream in the southwest U.S. and other high isolation regions around the world," Weimer said.
Within days of that announcement several researchers reported progress in overcoming one of the main barriers to cost-effective production of hydrogen. Commercial hydrogen production today requires the use of platinum as a catalyst, which now sells for about $18,000 an ounce.