Environmental Engineering Reference
In-Depth Information
some other chemicals in it. The
steps needed to get as pure a
hydrogen fuel as possible all
require some type of energy
input. In the end, producing
hydrogen fuel makes sense only
if the amount of energy you put
into making it is far less than
the amount of energy you get
out of the hydrogen fuel when
it is used.
Each of the major processes
that are now being used or
considered to produce hydrogen
that will be used in hydrogen
fuel have both benei ts and
downsides. All of the processes
have an energy cost—but in the
end, the amount of energy provided by the hydrogen fuel is far
in excess of the cost in energy to produce it.
u
How Much
Hydrogen Is Needed?
According to the U.S.
Department of Energy,
once hydrogen has become
established as an energy
carrier, the United States
would need about 40 million
tons (36.3 million metric
tons) of hydrogen per year to
provide enough electricity for
25 million homes and enough
fuel for 100 million vehicles.
Hydrogen from High-Temperature Steam
Natural gas provides about 23 percent of the energy used in the
United States. The natural gas is found in oil deposits, coal beds,
and even a type of rock called oil shale. Natural gas is made
almost entirely of the chemical methane.
Natural gas can also be used to make hydrogen fuel. About
95 percent of the hydrogen produced today in the United States
is made through a process called
steam-methane reforming
.
During this process, the methane that is in natural gas reacts
