Warning: The Hydrogen Economy May Be More Distant Than It Appears

9. FUEL CELL CARS CAN DRIVE HUNDREDS OF MILES ON A SINGLE TANK OF HYDROGEN
A gallon of gasoline contains about 2,600 times the energy of a gallon of hydrogen. If engineers want hydrogen cars to travel at least 300 miles between fill-ups-the automotive-industry benchmark-they´ll have to compress hydrogen gas to extremely high pressures: up to 10,000 pounds per square inch.


Even at that pressure, cars would need huge fuel tanks. â€High-pressure hydrogen would take up four times the volume of gasoline,†says JoAnn Milliken, chief engineer of the Department of Energy´s Office of Hydrogen, Fuel Cells and Infrastructure Technologies.


Liquid hydrogen works a bit better. GM´s liquid-fueled HydroGen3 goes 250 miles on a tank roughly double the size of that in a standard sedan. But the car must be driven every day to keep the liquid hydrogen chilled to â€253 degrees Celsius-just 20 degrees above absolute zero and well below the surface temperature of Pluto-or it boils off. â€If your car sits at the airport for a week, you´ll have an empty tank when you get back,†Milliken says.


? IF NOT HYDROGEN, THEN WHAT?
The near-future prospects for a hydrogen economy are dim, concludes The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs, a major government-sponsored study published last February by the National Research Council. Representatives from ExxonMobil, Ford, DuPont, the Natural Resources Defense Council and other stakeholders contributed to the report, which urges lawmakers to legislate tougher tailpipe-emission standards and to earmark additional R&D funding for renewable energy and alternative fuels. It foresees â€major hurdles on the path to achieving the vision of the hydrogen economy†and recommends that the Department of Energy â€keep a balanced portfolio of R&D efforts and continue to explore supply-and-demand alternatives that do not depend on hydrogen.â€

Of course, for each instance where the study points out how hydrogen falls short, there are scores of advocates armed with data to show how it can succeed. Physicist Amory Lovins, who heads the Rocky Mountain Institute, a think tank in Colorado, fastidiously rebuts the most common critiques of hydrogen with an armada of facts and figures in his widely circulated white paper â€Twenty Hydrogen Myths.†But although he´s a booster of hydrogen, Lovins is notably pragmatic. â€A lot of silly things have been written both for and against hydrogen,†he says. â€Some sense of reality is lacking on both sides.†He believes that whether the hydrogen economy arrives at the end of this decade or closer to midcentury, interim technologies will play a signal role in the transition.


The most promising of these technologies is the gas-electric hybrid vehicle, which uses both an internal combustion engine and an electric motor, switching seamlessly between the two to optimize gas mileage and engine efficiency. U.S. sales of hybrid cars have been growing steadily, and the 2005 model year saw the arrival of the first hybrid SUVs-the Ford Escape, Toyota Highlander and Lexus RX400h.




Researchers sponsored by the FreedomCAR program are also investigating ultralight materials-plastics, fiberglass, titanium, magnesium, carbon fiber-and developing lighter engines made from aluminum and ceramic materials. These new materials could help reduce vehicle power demands, bridging the cost gap between fossil fuels and fuel cells.


Most experts agree that there is no silver bullet. Instead the key is developing a portfolio of energy-efficient technologies that can help liberate us from fossil fuels and ease global warming. â€If we had a wider and more diverse set of energy sources, we´d be more robust, more stable,†says Jonathan Pershing, director of the Climate, Energy and Pollution Program at the World Resources Institute. â€The more legs your chair rests on, the less likely it is to tip over.â€

Waiting for hydrogen to save us isn´t an option. â€If we fail to act during this decade to reduce greenhouse gas emissions, historians will condemn us,†Romm writes in The Hype about Hydrogen. â€And they will most likely be living in a world with a much hotter and harsher climate than ours, one that has undergone an irreversible change for the worse.â€