Harnessing the kinetic power of the wind using turbines is one of the best known forms of renewable energy. Maybe because the huge wind farms are hard to miss when driving or walking. Maybe because wind farms have attracted controversy as a result of their visual impact on the landscape and the noise of the turbines.
Energy from the wind can be converted into electricity or mechanical power and has been used as a means of production for centuries. The first windmills are believed to date back to ancient Greece. Early windmills were built on a vertical access before moving to the more familliar horizontal access design. These early windmills produced mechanical power and were most commonly employed to grind grain in the production of flour. Windmills were also used for pumping water either to remove the water from underground mines or for irrigation.
Today wind energy can be converted into electricity through the use of turbines. Large scale wind farms that can generate many megawatts of electricity are built in open areas or off shore.
The general principal of modern day windmills remains the same as their ancestors. However rather than millstones modern windmills turn turbines to generate electricity. The largest capacity turbine currently in operation is the Enercon E-126 which produces 7.6MW. A 10MW turbine is currently being developed by a number of companies. The turbine will normally be located with dozens of other windmills in huge wind farms. Projects such as the London Array offshore wind farm in the UK are capable of producing 630 MW of electricity. Enough to power 470,000 a for a year.
Wind power is perhaps the most controversial of all renewable energy sources due to the windmills impact on the environment. Many people consider the large wind turbines a blot on the landscape. Others object to the noise generated by the turbines as they rotate. This can be a particular problem where turbines are located close to neighbouring properties. In these circumstances the landowner where the windmill is located receives all of the financial benefit while neighbours suffer the noise pollution. A further criticism of the wind turbines has been their impact on migratory birds. The ideal location for wind farms on exposed hillsides subject to prevailing winds place the turbines directly in the path of birds migrating during the year. With the blade tip travelling at speeds of up to 200 mph significant numbers of bird deaths have been reported.