Why we need wind farms
Scientists are widely agreed that man-made climate change and its potentially catastrophic effects are becoming a reality and that we need to act quickly to preserve our environment.
Records show that the ten hottest years around the world have all been since 1990. In the UK we have seen increased incidents of major flooding in recent years.
Countries around the world have agreed targets to dramatically reduce levels of harmful emissions being released into our atmosphere and contributing to climate change.
The UK has pledged to cut emissions by 34 per cent of 1990 levels by 2020 and at least 80 per cent by 2050.
Wind power reduces the levels of harmful emissions into our atmosphere by displacing electricity generated through coal-fired power stations.
Not only do wind farms require no fuel because the wind is freely available, the UK is also the windiest country in Europe.
To make the most of these conditions and meet our targets for producing renewable energy we need both onshore and offshore wind farms. There are advantages to locating wind farms at sea, but it is also much more expensive and takes much longer to install turbines in the sea bed.
How wind farms work
We specialise in small to medium sized wind farms so our sites will typically be made up of between one and six individual wind turbines.
As the diagram shows, modern turbines consist of three blades mounted on a tower. The blades are connected to a generator, which creates electricity when the wind blows and the blades turn.
The electricity generated is converted to the required voltage on-site and then fed into the local distribution network.
Wind turbines range considerably in height. At our Roskrow Barton Wind Farm in Cornwall, the turbines measure 70m to the tip of the blade whereas there are operational onshore turbines of 198m at a site in Belgium. We always aim to select the most appropriate machines for the local landscape.
The reason turbines need to be tall is that wind speed increases with height, enabling more safe, clean energy to be produced.
Wind turbines begin working in winds of around 4 metres per second (roughly 10mph) and shut down to ensure safety in very high winds (above 25 metres per second, around 60mph or force 10 on the Beaufort Scale).
Conditions are usually within this range and wind turbines in the UK typically generate electricity around 85 percent of the time.
Wind farms and noise
The design of wind turbines has improved since the first commercial wind farms were built in this country in the early 1990s. This has led to turbines becoming much quieter. It is perfectly possible to hold a conversation very close to a turbine without needing to raise your voice.
We are required to ensure that turbine noise falls within strict limits and does not cause a nuisance to neighbours.
The best way to judge for yourself whether wind farms are noisy is to come and visit one. We regularly take groups around our operational sites so please contact us to arrange a visit.
Wind farms are safe
Studies have been carried out in recent years to gauge whether wind turbines have ill effects on human health. No scientific, peer-reviewed study has yet found that wind turbines are harmful to human health.
One phenomenon that has been identified in connection with wind turbines is known as shadow flicker. This can occur when the rotating turbine blades cast a rotating shadow across openings like windows at nearby properties.
However, we can take steps to prevent this becoming a problem for our neighbours. The number of times when the effect is likely to occur can be calculated and the turbine causing creating shadow flicker can be programmed to automatically shut down for this short period.
Wind farms and wildlife
Many organisations, including the RSPB, have stated that climate change poses the greatest threat to our natural environment.
When we are developing a wind farm we are required to carry out detailed environmental studies to ensure that local habitats would not be adversely affected. We always take care to site turbines well away from bird and bat migration routes to minimise the danger of collision.
In some cases we have also developed site-specific environmental management plans enabling us to improve local habitats at the same time as building the wind farm.
Wind farms are not a permanent feature of the landscape
Although wind farms require plenty of space to operate, their actual footprint is very small. Typically they only occupy around one per cent of the site. This means that agriculture can and does continue right up to the turbine bases.
Additionally this also helps make onshore wind turbines relatively simple to decommission at the end of their working lives.
Wind turbines have an expected lifetime of 25 years and at the end of this period they can be removed and the land restored to its former appearance. Under current planning legislation, the land does not become classed as "brownfield" or previously developed land.
Wind farms and the environment
In 2010 our operating wind farms generated a total of 45,308,000 units (kWh) of renewable electricity. This is enough clean energy to meet the annual needs of approximately 10,377 homes.
A wind farm in the UK usually generates enough green energy in the first six to nine months of its 25 year lifespan to match all the energy required to manufacture and install the turbines.
