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Fueling the Future

David Goodstein

The Hydrogen Economy: The Creation of the Worldwide Energy Web and the Redistribution of Power on Earth. Jeremy Rifkin. viii + 294 pp. Tarcher/Putnam, 2002. $24.95.

The age of oil is about to end, which will come as a surprise to most people. Depletion of the rest of the fossil fuels may not be far behind. And if we do go on merrily burning up the planet's legacy, the result may be irreversible damage to our climate. This crucially important idea is the starting point of The Hydrogen Economy, a new book by Jeremy Rifkin, a former peace advocate who now crusades against biotechnology and various other perceived ills.

Rifkin believes that oil will be replaced by hydrogen fuel cells. Unlike the oil economy, which requires a top-down, capitalist-corporate order, the hydrogen economy will be something like the Internet, he says, with users who are also providers, generating their own hydrogen and sharing any surplus on the Hydrogen Energy Web. After all, unlike oil, hydrogen is everywhere: It's the most common element in the universe, the "forever fuel" that we can never run out of. The revolution brought about by the hydrogen economy will lead to a democratization of society and give a whole new meaning to the word globalization.

But wait a minute. Doesn't Rifkin understand that it takes energy to generate hydrogen from water, or from any other source? Well, yes, he even says so in a couple of places, but he seems to have trouble holding that thought. And when he does come to grips with it, he believes all the energy will come from "renewable resources—photovoltaic, wind, hydroelectric, geothermal, and biomass." There will be no nuclear reactors in a world designed by Jeremy Rifkin. At present, all the renewables on Rifkin's list aside from hydroelectricity collectively generate less than 1 percent of our energy needs.

Is Rifkin's proposed solution physically possible? Well, yes, sort of, but it's extremely implausible that all the power generated today by fossil fuels, about 10 terawatts worldwide, could ever be replaced from those sources. Biomass is a terribly inefficient use of sunlight. There are only a few places on Earth where enough geothermal energy to generate electricity is within drilling distance of the surface. Hydroelectric capacity is already saturated, and wind is an intermittent, low-density (and often ugly) source of power. According to an article by Martin I. Hoffert and colleagues in the November 1, 2002, issue of Science (298:981–987), to replace the 10 terawatts with photovoltaics would require an array covering more than 200,000 square kilometers, whereas all the photovoltaic cells shipped between 1982 and 1998 would cover only 3 square kilometers.

Our best hope in the short run is that somebody will start building nuclear power plants in a hurry, before the oil starts to run out. In the longer run, when the fossil fuels are gone or sequestered and the uranium starts to run low, if we haven't yet brought thermonuclear energy under control, heroic measures like huge arrays of photovoltaics on Earth, or somewhat smaller ones in space (where the solar flux is about 8 times the average at the Earth's surface), may be in order. That is not to say we should not do our best to develop renewable energy sources. We certainly should. But they will not replace fossil fuels anytime soon.

Rifkin is certainly right to say that we will soon start running out of oil, that continued burning of fossil fuels is a grave threat to the Earth's climate, and that hydrogen, either in fuel cells or by combustion, is the best bet for the future of transportation. He has correctly identified the biggest problem we have. But this book is not part of the solution.—David Goodstein, Physics, California Institute of Technology

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