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Fuel cells are an emerging technology in the energy sector
that offer significantly lower or zero emissions of harmful
pollutants. A fuel cell is an electrochemical device that converts
hydrogen fuel directly into energy without combustion. The only
products of the fuel cell electrochemical reaction are electricity,
heat and water.
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| Copyright Ballard
Power Systems |
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A fuel cell is
similar to a battery in that both release energy. However,
the fuel cell is fundamentally different than a battery.
A battery merely stores and releases a finite amount of
energy before it needs to be recharged. A fuel cell, in
contrast, acts more like an engine in that it produces
energy indefinitely as long as it is provided with fuel.
A fuel cell consists of two electrodes - the anode and
cathode - separated by an electrolyte. Hydrogen is introduced
as a fuel on the anode side of the fuel cell. When the
hydrogen comes in contact with the anode it dissociates
into a proton and an electron. The proton travels through
the electrolyte membrane while the electron must travel
through an external electric circuit, thereby generating
an electric current. When the proton exits the membrane
on the cathode side of the fuel cell, it combines with
oxygen to produce pure water and heat (the only byproducts
of this reaction). |
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| Photo courtesy of Fuel
Cell Today |
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The fuel required to operate a fuel
cell depends entirely on the type of fuel cell being used. Proton
exchange membrane (PEM) fuel cells require pure hydrogen, which
can be sourced either as pure hydrogen or through the processing
or 'reforming' of hydrocarbon fuels such as natural gas.
Solid oxide fuel cells (SOFCs) and molten carbonate fuel cells
(MCFCs) operate at higher temperatures than PEM fuel cells.
SOFCs and MCFCs can convert hydrocarbon fuels, such as natural
gas, directly into electrical power without the use of an external
fuel-processing step.
Fuel cells are currently being developed by some of the largest
corporations in the world for use in automotive applications,
stationary power and portable power applications. These technologies
are expected to revolutionize the way in which our world generates
power in the future. |
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