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Environmental Issues By Alan J Hartley |
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Solar Energy |
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Solar Energy, which of course comes
from the Sun, falls on the Earth in abundance and it has been calculated
that some 89 petawatts of sunlight reaches the Earth's surface, which is
almost 6,000 times more than the whole World's 15 terawatts of average electrical
power Photo voltaic power cells convert
sun light directly into electricity, but the resulting power needs to be
altered, from DC to AC by an inverter, for domestic use. Although systems have a high set
up cost they have virtually no running costs and to overcome the
installation costs many Governments are offering various financial
incentives to manufacturers and the public to encourage take up of
installations. This Although solar energy is used to generate electricity in more than 100 countries, at the moment this represents a tiny 0.15 percent of global demand for power. It is hoped that increasing demand for Solar will drive down production costs as well as increase research and cell efficiency. Currently cells are made based on Silicon crystals and some toxic metals such as Cadmium. This has led to concerns over the hidden cost of their safe disposal in years to come, but with new reclamation techniques being developed all the time this may not be a problem. A big problem with Photo Volataic
Cells is that they are relatively inefficient and rarely operate at
maximum Solar Cells are also proving their worth in remote locations such as on boats, traffic signs and for remote telephones where the DC current is usually fed into a battery to be drawn on later as required, or else used at a constant rate as for irrigation pumps. Developing countries are making more use of solar power generation in some ways than we are in the West. India has introduced a rural lighting program to provide solar powered LED lighting to replace kerosene lamps. Other more exotic ways that Photo Volataic cells are being employed are to power cars. Indeed there has been a race across Australia for several years now and many more are springing up around the World. A Solar Powered plane has recently spent over 24 hours in the air in continuous flight with all of its power generated by photo cells that created enough surplus in daylight to charge batteries to power it at night. A 14.5 metre Solar Powered ferry runs on the Serpentine lake in London's Hyde Park. The pleasure boat, that carries 42 passengers at some 4 knots, utilises 27 solar panels to generate more than 2KW and has back up batteries that will enable it to travel in total darkness for 20 miles. Perhaps belonging in the realms of fantasy is one idea to install Solar power cells in the surface of a roadway. The theory is that the road surface is generally free of obstruction to the Sun and if the idea works there is enough roadway throughout the World to generate the World’s electricity. |
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consumption. The problem is not in the quantity of power, but
how to harness it. As far back as ancient Greece scientists realised
that glass could be used to focus the suns rays to heat water in a
bottle. Modern science has developed the idea further to create Solar
Furnaces 
happened in Spain and Germany, who are the European
leaders in the field, and created some 10,000 manufacturing jobs in
Germany alone. Much of the electricity generated by Photo Voltaic Cells is
created domestically, but there are several commercial power stations in
both Germany and Spain as well as a 25 mega watt plant in Florida that
has over 90,000 solar panels. The Worlds biggest Solar energy plant,
that is currently being constructed is in California, will generate
550 MW at a cost of over 1 billion dollars.
efficiency due mainly to the angle of the sun and
adverse weather
conditions. Another drawback with the domestic use of AC (after the use
of an inverter) energy created with Solar cells, is that the energy
usage has to be matched with that created, or else, I believe, equipment
may not be powered correctly and may be damaged. Consequently, the AC energy
created is normally fed into the National Grid and can't be used by the
householder in the event of a general power cut. However, from a domestic users point of view, if enough of
the population with a suitable South facing house roof, have systems
installed they can make a valuable contribution to the nations green electricity
generation. Prince Charles is a firm believer and has just been granted
permission to install a large system on Clarence House in London.