NRDC: No Breathing in the Aisles: Diesel Exhaust Inside School ...

Fuel Cell Buses
There are a number of competing fuel cell technologies out on the market today, but the fuel
cell attracting the most interest relies on Proton Exchange Membrane (PEM) technology.
PEM fuel cell technology is based on the conversion of chemical energy into a usable form of
energy and heat that occurs without any combustion phase. Fuel cell technology results in
near-zero emissions, with the potential for zero emissions when pure hydrogen is used. Fuel
cells are similar to batteries in their use of chemicals separated by an electrolyte that reacts
and produces an electric current. 86 Unlike a battery, fuel cells are not charged. Instead, the
reactants are fed continuously to the cell. Fuel cells run on pure hydrogen but have the
potential to operate on a variety of other fuel types when reformed into pure hydrogen. These
fuel types include methanol, ethanol, and natural gas. 87 Automobile manufacturers and oil
companies are also researching ways to operate PEM fuel cells that can reform gasoline and
diesel fuel into pure hydrogen. Although fuel cells are not available on the market today for
school bus application, there are demonstration transit buses powered by hydrogen fuel cells
operating in several countries. Most of the major automakers have committed to commercializing
fuel cell passenger cars within the next few years.
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