In principle, a fuel cell
operates like a battery. Unlike a battery, a fuel cell does
not run down or require recharging. It will produce energy in
the form of electricity and heat as long as fuel is supplied.
A fuel cell consists of two
electrodes sandwiched around an electrolyte. Oxygen passes
over one electrode and hydrogen over the other, generating
electricity, water and heat.
Hydrogen fuel is fed into the
"anode" of the fuel cell. Oxygen (or air) enters the
fuel cell through the cathode. Encouraged by a catalyst, the
hydrogen atom splits into a proton and an electron, which take
different paths to the cathode. The proton passes through the
electrolyte. The electrons create a separate current that can
be utilized before they return to the cathode, to be reunited
with the hydrogen and oxygen in a molecule of water.
A fuel cell system which
includes a "fuel reformer" can utilise the hydrogen
from any hydrocarbon fuel - from natural gas to methanol, and
even gasoline. Since the fuel cell relies on chemistry and not
combustion, emissions from this type of a system would still
be much smaller than emissions from the cleanest fuel
combustion processes.
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