Air moves around the Earth because of the differences in temperature and atmospheric pressure that exist. Wind turbines harness the movement of air to produce energy. They do not emit any greenhouse gases and air pollutants, apart from those involved in their construction. The wind turns the blades which turn a rotor shaft. The resultant mechanical power is used to drive an electricity generator. Wind turbines are often grouped together in wind farms. They offer a highly sustainable form of energy.
Wind power has very promising potential in the UK as it lies in the path of Atlantic depressions (low-pressure systems), which bring windy weather. The UK currently has over 70 onshore wind farms, and it is thought that wind power could be supplying 10% of the UKs electricity by the year 2025.
Wind farms provide a clean source of energy, but they do have some disadvantages. To some, they have a detrimental visual impact, and can be noisy in windy conditions. Suitable locations for wind farms are often in areas of scenic beauty and so careful consideration needs to be given before they can be built.
It is estimated that the UK has a very large offshore wind resource. As well as being sited on land, the scope for setting up wind farms out at sea, where strong winds blow more consistently, is now under investigation. "Offshore" wind power, as it is called, involves fixing the bases of the wind turbines firmly to the sea bed and ensuring that the turbines can withstand the prevailing conditions, which are much more hostile than those on land. Currently there are 13 ofshore windfarm in UK waters, most off the coasts of East Anglia, Lancashire and Cumbria.