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Hydrogen Energy
Hydrogen is
the lightest and the most plentiful of all gases. Hydrogen is not freely
available but it is found in compound
forms such as in water(H2O).,
fossil fuels including methane(CH4),
propane, coal and petroleum and in biomass.
Hydrogen is a powerful energy carrier which has been used variously
in the past for industrial activities and as fuel for automobiles. It is
a clean-burning fuel and is therefore considered
environmentally friendly.
Hydrogen can be considered only "partially renewable energy resource" because it is not
freely available. It requires the decomposition of hydrogen containing
compounds into hydrogen and other constituent substances before use.
Methane, for instance, will be decomposed into hydrogen and carbon
elements. The decomposition can be
very expensive and sometimes contribute to environmental pollution (i.e.
the production of greenhouse gases). However, hydrogen, though entirely
renewable, provides an alternative energy
source to fossil fuels because it is an energy source with reduced level
of GHGs emission generation .(i.e. a low carbon generating energy source).
Obtaining Hydrogen:
The two approaches that have been used for obtaining Hydrogen from
compounds are: Stream reforming to separate hydrogen from fossil fuels and
carbon compounds e.g. methane(CH4)
and electrolysis to separate hydrogen from water.
In Stream reforming, hydrogen containing compounds are heated
to
very high temperature and pressure
to separate the hydrogen gas from the carbon chains.
This gas then goes through a clean-up process to remove substances such as
sulphur. After the clean-up, the two remaining gases
(hydrogen
and carbon dioxide)
are separated, by stripping the carbon from the hydrogen atoms.
The hydrogen is burned in a specially modified gas
turbine to make electricity.
The carbon dioxide is compressed and transported
through a pipeline and then injected deep underground into the depleted
oil and gas fields or coal beds, where it is stored safely and
permanently.
Carbon
dioxide
(CO2)
resulting from this process is
injected into the reservoirs
to flush out reserves of oil or gas that would otherwise be left behind.
Stream
forming generates GHGs thereby aiding global warming. Electrolysis is
seldom practiced; it is an expensive process.
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