Environmental Engineering Reference
In-Depth Information
The electrical current then returns to the fuel cell, completing
the electrical circuit. When the electrons return to the fuel cell,
they come into contact with outside air that has been pulled
into the fuel cell at the second electrode. This air contains
oxygen. The oxygen that has been pulled in combines with the
loose electrons. The oxygen also combines with the positively
charged hydrogen ions that have traveled from the other
electrode. Hydrogen and oxygen combine to form water, which
drains from the fuel cell.
Meanwhile, more hydrogen
and oxygen go into the fuel cell,
and the process is repeated
over and over again. The result?
Electricity! As long as there
is a supply of hydrogen and
oxygen, a fuel cell can keep on
producing electricity.
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Fuel Cell Stacks
Some huge fuel cells produce
a great deal of electricity.
Usually, though, the chemical
reaction in fuel cells produces
only a small amount of
electricity—about 0.7 volts.
Compare this to a regular C
size battery that you might
use in a toy or fl ashlight.
A C battery produces 1.5
volts. Scientists have learned
that they can join together,
or “stack,” fuel cells. This
increases the total amount of
voltage that a set of fuel cells
can produce.
How Are Fuel Cells
Used?
How many things can you think
of that use electricity? There
are big things, of course, like
the refrigerator, television set,
and computer in your house.
Your house probably gets its
electricity from a power plant
that burns fossil fuels, but fuel
cell stacks could also be used
to produce this electricity. They
