Introduction
Philosophically,
if not exactly technically, electricity generation by means of wind turbines is closely
related to Solar Power. It’s the sun which ultimately causes the winds. It does so
because it heats the surface of the earth, either at sea or on land. This heat is
transferred to the lower air and, as this warmed air consequently becomes less dense than
the upper level colder air, a pressure gradient is formed. Air naturally moves from higher
to lower pressure areas. The result is wind. As it’s caused by heat from the sun it
is also a virtually inexhaustible resource.
After
that the rotation of the earth plays a part. So does friction between the surface of the
earth and the wind moving just over it. Interaction between the winds that have started to
generate and physical features such as mountains and valleys all play their part. In a
cumulative way, all of these factors combine to create a complex situation that is
extremely difficult, even in this age of sophisticated computers and computer programs, to
predict.
People
have been trying to capture and use the wind for centuries. Sailing ships and windmills
are only two examples, the origins of which are lost in antiquity. What’s interesting
is that it has taken the post wind-power age of fossil fuel electricity generation to
drive the industrial revolution and later the electronic revolution, to enable the
development of a body of technical knowledge that allows current generation wind power
turbines to be at a level of sophistication and scale that the people who built the early
windmills would find to be nothing short of incredible. In other words, if, as is
postulated elsewhere, the current reliance on fossil fuels for electricity generation is
to necessarily diminish in favour of solar and wind power, it will have been the
exploitation of those same fossil fuels that will have made such a development possible,
at least in the time scale in which it happened.
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