Below are some of the most frequently asked questions about wind energy. The answers are usually short, and often refer to more in depth explanations given elsewhere. Any other questions you have that you cannot find here, you may find the answer in our reference section yet.
Just as there are some frequently asked questions about wind turbine technology, there are some common misunderstandings. Read the myths at the top of the page about wind power and make sure you know your facts!
Are wind turbines noisy?
Wind turbines are not noisy. There are strict guidelines on wind turbines and noise emissions to safeguard the protection of residential amenities. Mechanical noise from turbines has been rendered almost undetectable with the evolution of wind farm advancements over the past decade. The main sound that can be heard is the aerodynamic swoosh of the blades passing the tower, but It is possible to stand underneath a turbine and have a conversation without having to raise your voice. In fact as the wind speed rises, the sound from the wind masks the noise made by wind turbines anyway. For more information, read the facts about noise from wind turbines section or why not visit a wind farm and hear it yourself.
Do wind turbines produce low frequency noise?
If you sit and listen there is always low frequency noise present in any quiet background and it can be produced by things such as machinery and transport or natural sources such as the sea, wind and thunder. It has been repeatedly shown and accepted by experienced wind noise professionals undertaking turbine noise tests in the UK, Denmark, Germany and the USA over the past decade, that the levels of low frequency noise and vibrations from modern upwind configuration wind turbines are at a very low level. So low in fact that they lie below the perception of hearing..
For more information read BWEA's full report on Low Frequency Noise and Wind Turbines.
Why don't turbines look like old fashioned windmills?
The idea of the old fashioned windmill fills most people with nostalgia, and some people favour the aesthetics of them to that of the modern equivalents. But just because wind turbines are modern now, doesn't mean they won't look just as good over time.
A modern turbine is basically an improved windmill. Every feature of their design has been optimised for the best possible results, making them far more proficient at generating electricity than old style windmills. To design and build them in an old-fashioned style would just result in more expensive electricity and costs.
Why are all the wind turbines not out to sea?
To meet the UK's demanding targets on climate change a mix of both onshore and offshore wind energy is needed. At the moment onshore wind makes it more cost effective for the turbines than development offshore. Also offshore wind farms can take a lot longer to build, as the sea is naturally a more harsh environment to work in. To expect all wind farms to be offshore would destroy our renewable energy targets and obligation to tackle climate change.
We are lucky here in the UK to have excellent winds both on and offshore. Our first offshore turbines at Blyth began producing electricity in December 2000. More offshore wind farms are now dotted in locations around the coast, and more are being erected or in planning stages at the moment. Visit our Offshore section in the clients tab for more information on offshore wind farms in UK waters.
Do wind turbines frighten livestock?
Sheep, cows and horses are not disturbed in the slightest by wind turbines. Wind farming is popular with farmers as they can get extra money from their fields without disrupting the main source of the land, be it for growing crops or grazing livestock.
Delabole was the first wind farm built in the UK, and the farmer, Peter Edwards, has a stud farm and riding school. He often rides around the wind farm on his horse.
How long does it take for a turbine to 'pay back' the energy used to manufacture it?
The relationship of energy used in building with the energy produced by the turbine is known as the 'energy balance'. It is sometimes known as the energy 'pay back' time, i.e. as the time needed to generate the corresponding amount of energy used during the instillation of the wind turbine or power station.
An average wind farm in the UK will 'pay back' the energy used during its manufacture and instillation within six to eight months. This compares well with coal or nuclear power stations, which take about six months.
How popular is wind energy?
Wind energy is one of the most popular energy technologies around with surveys showing that just over eight out of ten people are in favour of wind energy, and less than one in ten (around 5%) are against it. The rest are undecided.
How safe is wind energy?
With over 25 years operating experience and with more than 70,000 machines installed around the world, wind energy is one of the safest energy technologies around. It has been recorded that no member of the public has ever been injured during the normal operation of a wind turbine.
Does wind farming affect tourism?
There is no evidence to suggest wind farming has a detrimental affect on tourism. The UK's first commercial wind farm at Delabole enjoyed more than 350,000 visitors in its first ten years of operation. In fact a MORI survey in Scotland showed that 80% of tourists were interested in visiting a wind farm. In addition, wind farm developers are often asked to provide a visitor centre and viewing platforms.
What can I do to help wind energy?
Don't be one of the silent majority. One of the most best things you can do is to help win the debate on wind energy. Wherever the occasion occurs respond to letters in papers, participate in radio phone-in programmes, or join debate forums. You can find out about projects in your area which need support at Yes2Wind and remember to sign up to show your support for wind energy in the national Embrace the Revolution campaign.
As part of the Government's obligation on electricity companies to source 20% of their supply from renewable energy you can not only choose who supplies your electricity but even where that electricity comes from. 'Green' electricity generated from renewable resources is available from all electricity suppliers. You can compare the different green tariffs available online at uSwitch.com.
You can even have your own wind turbine installed at your home or business, find out more in our wind turbine section.
I want to visit a wind farm, where is the nearest one to me?
There are plenty of ways of finding out about wind farms in your area and ones that are in planning stages. One of the best ways is to search is the British Wind Energy Association (BWEA) web site.
What are wind turbines made of?
The towers are mostly made from steel and generally painted light grey. The blades are made of either glass-fibre reinforced polyester or wood-epoxy. They are finished in a matt light grey colour because this is the colour which is most unobtrusive under most lighting conditions and help to reduce reflected light.
What size are they?
The towers can range between 25 to 80 metres in height. The wind turbines have rotor spanning up to 65 metres in diameter, while in developing countries smaller machines, around 30 metres are typical.
How is electricity made from a wind turbine?
Effectively a wind turbine works in exactly in the reverse way to a fan. Instead of using electricity to make wind, like a fan, turbines use the wind to make electricity.
Mostly all turbines have a central hub that the blades rotate around. Connected to the hub is a gearbox and a generator, located inside something called the nacelle, where all the electrical components are located.
Most wind turbines consist of three blades which stand facing into the wind; the wind turns the blades, which in turn spins the shaft, which is connected to a generator and this is where the electricity is made. The generator is the machine that uses the mechanical energy to produce the electrical energy, in contrast with an electric motor which does the opposite.
How strong does the wind have to be for the turbines to work?
Wind turbines can operate anywhere from about 10 miles an hour (4-5 metres/second) to 50+ miles (25 metres/second) an hour where they shut down due to the too extreme gale force winds. The maximum power output is around 33 miles per hour (15 metres/second).
How fast do the blades turn?
Machines operate at variable speeds, with the blades rotating at anything between 15-20 revolutions per minute at constant speed..
How much space do wind turbines need?
A standard wind farm of 20 turbines will extend over an area of about 1 square kilometre, but only 1% of the land is used for the turbines, electrical infrastructure and access roads. The rest of the land can be used for farming or natural habitat.
What happens when there is no wind?
When there is no wind, electricity continues to be supplied by other forms, such as gas or coal-fired power plants. The U.K. electricity system is mainly made up of large power plants, and the system is set up to cope if one of these goes out of action. It is entirely possible to have up to 10% of the country's electrical needs met by alternating energy sources such as wind energy, without needing to make extensive changes to the way the system operates.
How long do wind turbines last?
A wind turbine by and large will last about 20-25 years. At some stage, as with a car, some parts may need replacing.
The first of the mass-produced turbines celebrated its 20th birthday in May 2000. The machine has operated progressively well throughout its life span, without requiring any of the major components to be replaced.
What happens when a wind farm is taken down/decommissioned?
The local authority will have clauses in planning permission stating what must happen on decommission. Typically these may require all visible traces of the wind farm to be removed, from the turbines to the service tracks. Each case is different though and will depend upon the size and geography of the development.
The concrete bases can be removed, but sometimes to disturb the ground less it is better to leave them underground. They can be covered with peat or stone etc, and the site returned as close as possible to its initial state. The turbines often have enough scrap value to cover the costs of the ground renovation.
In comparison the reversibility of a wind farm is so simple compared to say problems connected with decommissioning a nuclear power plant, or a coal or gas fired plant.
How efficient are wind turbines?
The hypothetical maximum amount of energy a wind turbine can extract from the wind blowing is just under 60%, also known as the 'Betz limit'. However due to the fact that the fuel for turbines is free the meaning of efficiency is a little redundant. The main interest is not efficiency for its own sake, but improving productivity output to unable the price of wind energy to lower.
Why don't wind turbines have lots of blades?
The optimum number of blades for a turbine depends on the exact job it has to do. For turbines to generate electricity they need to run at high speeds, however they don't need much turning force. For these machines it is optimally best for them to have three or two blades. A wind pump, on the other hand, operates with plenty of force but not much speed and thus requires many blades.
Why do some wind turbines have two whilst others have three blades?
The main reason for three blades over two is studies have shown they have greater aesthetic appeal. The negative is that every blade costs and weighs more and can be more difficult to install, particularly offshore.
Machines with two blades are cheaper and lighter, with higher running speeds, and the installation is easier. On the other hand two bladed machines can be noisier and are not as aesthetically pleasing, appearing 'jerky' when they rotate. The engineering ideal would be to have just one blade, and some one bladed prototypes were developed early on, but they didn't stand the test of time.
How much does it actually cost to make electricity from the wind?
The average for an onshore wind farm in a good spot is 3-4 pence per unit. It is competitive with other greener sources such as new coal at 2.5 - 4.5p and cheaper than nuclear power at 4 - 7p. But the cost of wind energy can vary according to many factors. Electricity from smaller wind farms can be more expensive for instance.
How much of the time do wind turbines produce electricity?
A modern wind turbine will produce electricity 70-85% of the time, but it creates various outputs depending on the wind speed. Over the space of a year, a turbine produces around 30% of its theoretical maximum output, also known as its 'load factor'. The load factor of conventional power stations is only slightly more with an average of 50%.
Could I be able to have a turbine for my garden or the roof of my house?
Simply, yes is the answer. Progressively more households, communities and small businesses are interested in creating their own electricity by using small scale wind turbines. For more information see the British Wind Energy Association (BWEA) web site for a fact sheet on it.
I want to build my own wind turbine
There is a very good book to check out on this subject, 'Wind Power Workshop' by Hugh Piggott, available from the Centre for Alternative Technology. It gives a brief idea of what is involved and how to build your own.
Isn't it cheaper to save electricity?
It is cheaper to save electricity than to generate it, by whichever method. In the Energy Efficiency Standards of Performance Review, it states the cost of energy efficiency measures as costing about 1.3 pence per kilowatt hour (per unit). The cost of wind energy is at the moment around 2.4 pence per unit. But, to fight climate change, the UK needs a mixture of both renewable energy technologies and energy efficiency measures.
How many wind farms/turbines are there in the UK?
For this information check out the British Wind Energy Association (BWEA) web site for the U.K. statistics.
How much electricity does one wind turbine produce?
One 1.8 MW wind turbine at a decent site can produce over 4,7 million units of electricity every year, that is enough to ensure the annual needs of over 1,000 households, or to run a computer for over 1,620 years.
