Environmental Engineering Reference
In-Depth Information
countries. In most countries the potential for wind power utilization is
enormous. Germany could provide one-third of its electricity demand and the
UK could theoretically cover even more than its whole electricity demand with
wind power.
Germany can be taken as example of the rapid development of wind power
and its integration into the electricity supply structures. Most of the established
utilities fear the competition and complain about the problems with line
regulation that result from fluctuations in wind power; however, some utilities
have demonstrated that improved wind speed forecasts can solve these
problems. Even some environmental organizations protest against new wind
installations. Their reasons are conservation, nature or noise protection;
indeed, some of their arguments are justifiable. On the other hand, wind power
is one of the most important technologies for stopping global warming. No
doubt, wind generators change the landscape, but if we do not get global
warming under control, coastal areas that would be protected by the reduction
in global warming resulting from wind generator installation will most likely
not exist far into the future.
The discussions of wind power make clear that a social consensus about
future energy policy does not exist. It is hoped that this consensus can be
achieved soon because the utilization of the enormous potential of the wind is
essential for an economical, sustainable electricity supply.
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Wind resources
The sun heats up air masses in the atmosphere. The spherical shape of the
Earth, the Earth's rotation and seasonal and regional fluctuations of the solar
irradiance cause spatial
air pressure differentials
. These are the source of air
movements. Irradiation oversupply at the equator is the source for
compensating air streams between the equator and the poles.
Besides the spatial compensation streams, less extensive air currents exist
due to the influence of local areas of high and low pressure. The Coriolis force
diverts the compensating streams between high and low pressure areas. Due to
the rotation of the Earth, the air masses in the northern hemisphere are
diverted to the right and in the southern hemisphere to the left. Finally, the air
masses rotate around the low-pressure areas.
Wind resources are particularly high in
coastal areas
because wind can
move unhindered across the smooth surface of the sea. Furthermore,
temperature differences between water and land cause local compensating
streams. The sunlight heats the land more quickly than the water during the
day. The results are pressure differentials and compensating winds in the
direction of the land. These winds can reach up to 50 km inland. During the
night the land cools much faster than the sea; this causes compensating winds
in the opposite direction.
