This page briefly answers some common queries regarding onshore wind. For further information, the wind industry association www.renewableuk.com amongst others have more detail on their websites.Are Wind Farms adding money to my fuel bills?
OFGEM produce a breakdown of the average household fuel bill, showing the costs of all the different elements that goes into making up a fuel bill, from the wholesale fuel costs, transmission, tax etc. Within this there is an ‘Environmental’ section, including a financial mechanism to encourage use of renewables called the Renewable Obligation (RO). In fact the results from OFGEM’s RO annual report show that onshore wind costs the average household about £5 a year. This is in stark contrast to the spiralling costs of the average fuel bill due to the rise in the cost of imported gas. The security of supply, by having onshore wind turbines in the UK making up an ever increasing proportion of our fuel mix should actually help to keep our bills lower, by reducing our dependence on imported fuels.
Efficiency is a slightly odd concept when it comes to wind. For a conventional fossil fuel power station, efficiency means the proportion of energy released from burning the fuel into useful electrical energy. This is generally in the region of about 35-45% for conventional power stations. This applies only loosely to wind, because the wind is free and inexhaustible, however the maximum energy recovery from wind is approximately 60%.
Studies known as Life Cycle Assessments have been performed on wind turbines/farms. This calculates all the energy used and emissions expended with making, transporting, building, operating and removing a wind farm. These calculations can be compared to the energy produced (and thus emissions saved) to work out a ‘pay back’ period. This depends on several factors including the size and location of the site but generally this payback will take 6-12 months, which is comparable with conventional fuels.
One 2 MW wind turbine at a reasonable site would produce over 6 million kWh of electricity each year, enough to meet the annual needs of over 1,100 households.
Wind turbines start operating at wind speeds of 3 metres per second (around 7 miles per hour) and reach maximum power output at around 12.5 metres per second (around 28 miles per hour). At very high wind speeds, i.e. gale force winds, (25 metres per second, 56+ miles perhour) wind turbines shut down automatically to protect their structural integrity.
Wind turbines are not inherently noisy. Modern, upwind turbines are significantly quieter than their older predecessors mostly due to the elimination of mechanical noise. Some noise is produced by the blades sweeping through the air, but there are strict guidelines to ensure that noise emissions do not affect residential amenity in the vicinity of a wind farm. It is possible to stand underneath a turbine and hold a conversation without having to raise your voice. As wind speed rises, the noise of the wind itself usually masks the noise made by wind turbines. The phenomenon known as low frequency noise can occur from a variety of man-made and natural sources. Low frequency noise and vibration from wind turbines are at a level generally below the threshold of perception.