# Wind Power Extension ```Wind Power – A Viable Solution to the Energy Crisis?
For maximum efficiency, wind turbines are built to optimise the wind power they harness. For example, the blades
of a wind turbine must be at least 10m above the ground, as the wind closest to the ground experiences surface drag
as it passes over the Earth’s surface.
Wind turbines take energy from the wind,
creating a “shading” effect upon the land
directly beyond them, where the wind has
less energy (see diagram). Wind turbines are
therefore built with a separation much
greater than this “shading length”, which
ranges from 5-10 times the diameter of the
In the following calculations, you will determine the area required for a wind turbine farm to replace a fossil fuel
power station, and estimate the numbers and area that would be needed to meet the UK’s power requirements.
1. First calculate the area of land required for one wind turbine, so that it is correctly separated from its
neighbouring turbines. Assume that the turbine has a blade diameter of 50 m, and assume a separation
length of 10 blade diameters. Hint: a small “bird’s eye” sketch may help you to visualise this
2. Now calculate the area that would be required by a wind turbine farm with a power output equal to a fossil
fuel power station of 1 GW. Hint: take an average power output of 1 wind turbine as 2 MW
3. Compare the area of this wind farm with the area of the Royal Borough of Kingston upon Thames, 37.25 km2,
and Greater London, 1572 km2.
4. Calculate how many people this wind turbine farm could support, assuming that the average power
consumption per capita in the UK is 631 W. Compare this figure to the UK population of approximately 62
million.
5. From your calculations, do you think wind turbines are a viable solution for all of the UK’s energy
requirements. If so, where would you place the turbines.
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