Hydrogen Reality Check

Fuel cells won't significantly dent fuel consumption for 50 years -- we need to look elsewhere.

High oil prices and concerns about the long-term availability of oil have U.S. government officials singing the praises of hydrogen fuel cells as a solution to our nation's transportation energy problem. But fuel cells, while a promising technology, could take more than 50 years to have a significant impact on gasoline consumption, according to estimates by MIT researchers. On the other hand, improved internal combustion engines and lighter vehicles could offset energy consumption much sooner, especially if consumers have incentives to buy them and manufacturers to make them.

"The potential for hydrogen fuel cells having an impact that you'd notice is a long way away," says John Heywood, professor of mechanical engineering at MIT. The estimates assume that competitive fuel cell vehicles will be available within 15 years, an achievement that will require improvements, for example, in hydrogen storage and production and fuel-cell costs. But even if and when fuel-cell vehicles come with the price and performance that consumers want, it will still take decades more before such new vehicles work their way into widespread use.

One factor slowing the impact of any new vehicle technology -- whether advanced internal combustion engine, hybrid, or fuel cell -- is the average lifespan of a car, which is about 15 years, according to Heywood. Even as people buy cars with new technologies, old ones stay on the roads, continuing to burn fuel and emit carbon dioxide.

Also, as the example of hybrids shows, the market share of vehicles with radical new technologies increases only slowly, and it can take years before the new technology starts to appear in more than one vehicle in a manufacturer's fleet. Hybrids were first introduced, in the United States, in 1999, and still only account for about one percent of vehicle sales. The MIT researchers estimate that, even after a competitive hydrogen fuel-cell vehicle is available, it will take roughly 25 years for these vehicles to make up 35 percent of new car and light-truck sales. And it will be an additional 20 years or so before these cars replace 35 percent of traditional vehicles on the road.

On the other hand, advanced internal combustion engines, which will likely be ready for the marketplace much sooner, and will require less retooling and so can spread through the fleet faster, could have a significant impact in about 20 years. Meanwhile, advanced, clean diesel engines and hybrids could both reach significant levels in about 30 years. In spite of the greater near-term promise of these technologies, however, there is no effort to develop them that's as far along as the federal hydrogen research programs. "We're not investing enough in developing a broad technology base we can draw on to deal with these problems," Heywood says.