Water in the hydrogen economy.

In E's May/June 2003 Advice and Dissent, Jim Bell of San Diego suggested a "fatal flaw" in the proposed hydrogen economy: a reduction in the planet's water inventory as molecular hydrogen is lost to outer space. But this does not seem a realistic concern.

Molecular hydrogen is reactive enough that all but about 0.04 percent of its current additions to the atmosphere (a million tons a year, nearly all from human activities) recombines chemically within the atmosphere, rather than escaping to outer space. Also, as is the case in today's large hydrogen industry, hydrogen leaks will be kept very small for economic and safety reasons. And switching to an all-hydrogen economy would probably release about as much molecular hydrogen as is now released by fossil-fuel combustion. Further, the water drizzled regularly into the upper atmosphere by small comets would exceed by at least hundreds of times any plausible water loss from even a very large and leaky hydrogen economy.

Amory B. Lovins, CEO Rocky Mountain Institute, Snowmass, CO