WIND ENERGY

The UK has the largest potential wind energy resource in Europe. This potential has yet to be fully realised. Wind energy applications in the UK range from small household turbines charging batteries to produce useful electricity in remote locations, to large wind farms producing electricity competitive with conventional power stations.

Modern wind turbines are divided into two major categories: horizontal axis turbines and vertical axis turbines and research advances have helped drop the cost of energy from the wind dramatically over the last 20 years. Renewable energy from the wind is considered a green technology because it has only minor impacts on the environment, producing no air pollutants or greenhouse gases.

Many respected sources state that wind power can provide at least 10% of total UK electricity supply without incurring any disruption to the system, or requiring any back up. Since the UK has a wind resource equivalent to several times the entire country's electricity needs there is enormous potential for development over and above the 10% target. It is also widely accepted that wind power plant in the UK generates electricity at some of the lowest prices in Europe.

Offshore wind.

Of all the renewable technologies, offshore wind has the potential to deliver the highest quantities of energy, however it is not competitive with onshore wind. Offshore wind energy has the added attraction that it has minimal environmental effects and, broadly speaking, the best resources are reasonably well located relative to the centres of electricity demand.

One of the attractions of offshore wind power is that wind speeds are generally higher offshore than on land. However, this is not the case in undulating countryside such as is found in the British Isles, Italy and Greece since here the winds in upland regions are enhanced, relative to ground level, by the altitude and by acceleration due to hill shape. In the UK, for example, onshore winds range up to around 9.5 m/s at hub height, whereas offshore winds at, say, 5 km from the shore are in the range 8.3-9 m/s.

Wind turbulence is lower offshore so this means that turbines are subject to less stresses from the wind, although this tends to be offset by the higher wind speeds and the need to design the structures against wave loads and wind/wave interactions. The need for more expensive foundations and the need to protect the turbines from the corrosive influence of salt spray, push up the costs of offshore wind energy relative to onshore and also the cost of grid connection at remote upland sites may be more expensive if grid reinforcement is required. However, set against these actual and potential extra costs is a reduction in the civil engineering costs due to the absence of access roads.