It is possible of course to generate electricity directly from
sunlight using silicone photovoltaic cells, and energy can be
harnessed from the sun in the form of heat by using solar
collectors such as mirrors or concave dishes and focusing the
sun's rays. This heat can then be used to generate steam and
produce electricity. This is a great system in theory, but the
problem is that the areas of the world which receive large
quantities of sunlight are not necessary the areas where the
electricity is most needed, so unless we can find a means of
transporting it to the point of consumption which may be
hundreds or even thousands of miles away there is little point
in following this route. Suggestions have been made that
generated electricity can be used to separate water into
hydrogen and oxygen by electrolysis and that the hydrogen
itself could be used as a fuel; this may be a possibility in
the future but research and development in this field is
hampered by the fact that oil is so much cheaper at present.
Wind power is becoming extremely popular right across the
world; there is a great deal of wind available so the
potential for generating huge quantities of electricity is
quite real. Perhaps the biggest drawback to this idea is the
fact that nature is pretty uncontrollable and regions where
there is steady predictable winds are few and far between or
unsuitable for the production of large wind farms. The result
is a feast or famine situation and since electricity is
required 24 hours a day seven days a week and not just when
the wind is blowing in a certain direction wind power cannot
answer the problem on its own. Once again, some means of
storing huge quantities of electricity would be the answer,
but we do not have this technology as yet.
Hydroelectric dams have been very successful in some parts of
the world. They work by holding back huge volumes of water,
which is then allowed to run through rotors which turn
dynamos. Two problems crop up here; the first is that there
are very few parts of the world that can accommodate systems
like this, and secondly building hydroelectric dams is a very,
very expensive process and it would be vital to have backup
systems in any case in the event of a failure of some sort.
Tidal energy is a possibility; again the greatest drawbacks
are the huge costs involved in building the necessary dams and
the geographical factor.
Finally we come to geothermal energy. In some parts of the
world this is quite easily tapped in regions with volcanic
activity but the drawback is the inherent instability of the
source; to put it bluntly one never knows when the volcano may
erupt! In more stable regions it is often possible to drill
hundreds or even thousands of feet into the earth, pump down
water and received steam back in exchange; systems like this
have in fact been in use for over a century but again that
there are limited regions of the world where this is possible.
So where does all this leave us? There is plenty of energy
lying around in one form or another, but our problem is not
only to collect it but also to transport it. If a safe and
portable means of storing bulk quantities of electricity can
be found then this will go an extremely long way towards
solving the Earth's future energy needs; alternatively there
is a distinct possibility that in the future mankind will have
to contemplate a hydrogen, rather than oil economy.
|
