Energy is whatever can be efficiently converted into heat
or motion to provide powder to run machines and vehicles
and to supply heat and light.
Energy sources are of
two types, renewable and nonrenewable. Most of the
industrial world is presently powered by nonrenewable
fossil fuels – coal, petroleum and Natural gas
– that once used, cannot be replaced. Fission
nuclear reactors are fueled by uranium or plutonium,
themselves finite energy sources. Spent uranium, however,
can be converted to fissile plutonium in a breeder
reactor, a process that makes nuclear energy almost
Nuclear technology, however,
has not yet developed either failproof reactors or
a safe method for disposing of nuclear wastes. The
development of nuclear fusion (whose end products
are harmless) has so far been hindered by the difficulties
of containing the fuels (plentiful light elements
such as hydrogen) at the extremely high temperatures
necessary to initiate and sustain fusion.
energy sources include the energy from water and wind
(i.e. Turbines, windmills and waterwheels); geothermal
energy, the earth's internal heat that is released
naturally in geysers and volcanoes.