By Sid Perkins
Fossil fuels are often reviled because they produce planet-warming carbon dioxide. However, replacing them with hydrogen gas–considered to be a clean-burning source of energy–may generate a different set of environmental problems, including large and long-lasting ozone holes, according to a new analysis.
The potential problems with hydrogen don’t stem from the oxidation of the gas itself, which produces only water vapor. Instead, drawbacks may arise from the almost inevitable leaks of hydrogen gas from facilities that produce it, containers that store it, and fuel cells that use it to generate electricity, says John M. Eiler, a geochemist at the California Institute of Technology in Pasadena, who has analyzed seepage rates from current hydrogen facilities.