Wind Power
Wind energy does not cause any pollution or contamination of land. It offers one of the fastest ways to increase the contribution of renewable energy and reduce CO2.
Wind turbines can be either horizontal axis (HAWT) or vertical axis (VAWT) with a variety of design blades and types. The most common are HAWT with one, two or three blades, which are technically described as low solidity. This refers to the solid section of swept area by the blade, which combined with the width of the blade determines the optimum tip speed. The power extracted from the wind to the turbine depends on the angular wind speed and torque. Torque describes when the centre of rotation begins to turn the blades of the turbine.
The amount of power generated by the wind varies according to the position and sighting of the turbine, depending on open terrain, sheltered and the height it is positioned. Predictions can be made to estimate the potential generation of the turbine according to the wind speed.
Environmental Impacts of wind
Most people have preconceived ideas in relation to the noise or visual impact a wind turbine has or is likely to have on the environment. These need to be compared with other factors and not treated in isolation.
It is important to consider acceptable noise levels of daily activities by comparison. A wind turbine from the distance of 160 metres will generate 45dB(A), by comparison to a noisy office (60dB(A)), inside a car (80dB(A)), or stereo music (80dB(A)). The main causes of noise are the mechanical noise caused by the gearbox or generator or the dynamic (whooshing) sound of airflow as it passes over the wind blades.
Visual impact may also be a concern depending on the location. Its presence should be considered in relation to other factors such as electricity pylons, mobile phone masts and other communications masts. Another factor is the fatality of bird life; the occurrence of this is relatively low at 1-2 per annum per turbine, lower than those killed in car collisions.
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