Questions and answers
Wind power - questions
If you are considering the possibility of installing your own wind turbine, this section is to help you make a decision. Having read these commonly asked questions, please contact us if you still have a query.
A wind turbine enables you to use your own green energy. In selling it back to the National Grid, you can earn money too!
Planning an installation
Can I own a wind turbine?
Wind turbines are ideal for domestic households, schools, higher education sites, community centres, farms and businesses. We offer a range of different types of small wind turbine models which can be installed in most locations. Your site specifics (such as location, wind speed and local landscape) will determine the best turbine type and size for your case.
How do I find out if my site is windy enough?
We provide a UK Wind Speed Database, which tells you the average wind speed in your area. All it requires is your post-code. The actual wind speed at your site will be influenced by local factors, such as trees, other buildings and, in particular, by the terrain. Wind movement around buildings is unpredictable, so it is best to site the tower some distance from buildings. A site with an average wind speed of 4.8 to 5 metres per second is generally sufficient enough to make installing a small wind turbine worthwhile.
If you have time, an effective technique is to monitor wind speed and direction for some months at the spot you plan to site the tower and the turbine.
What size turbine will I need?
This can be a difficult question to answer. Some guidance can be obtained from the BWEA site, for example, on their Calculations for Wind Energy page. Alternatively, we can perform a site survey to specify the correct size.
To check your annual consumption, check back over your last 4 electricity bills to give you the annual usage. You could install a turbine that is sized to provide just enough power for your own use, so that you use all the wind power available to meet your demand. You will need some means to 'top-up' your needs, which might be battery or generator power, or you could opt to be connected to the Grid. In the latter case, you would draw some power from the network to satisfy your overall need, for the times when the turbine is not providing power. If you are using a Grid connected system, then any excess generated power, left over after your own use has been satisfied, can be exported to your local network.
You are permitted to sell excess generated power to a Supplier under terms arranged with that Supplier. You will need metering equipment to measure the power exported.
We are able to assess the power requirements and likely wind generation of your particular site to see which turbine will suit your needs.
How tall are small wind turbines?
The turbines themselves are small; the main concern is the size of the rotor. They need to be above ground at a safe height. In general, the higher the turbine, the higher the wind speed experienced by the turbine and the smoother the air. Tower height varies from 6 to 25 metres depending on the turbine used. The rotor diameter of small wind turbines ranges from 2.5 to 11 metres depending on the model of turbine.
How much space do I need for a turbine?
Ideally, turbines should be sited as far away as possible from buildings or trees, which may block the wind and cause turbulence. As a guide, the wind turbine should be about twice the height of obstructions immediately in front of it (for at least the prevailing wind direction). In general, the turbine should be above the height of nearby obstructions that are within a distance of 10 to 20 metres of the tower heights.
You also need to consider installing the turbine and tower. It is best if the tower can be laid flat on the ground for servicing and maintenance. It also makes installation easier. This suggests a clear space equal to the height of the tower plus the rotor radius.
Do I need planning permission?
Small wind power installations may require planning permission; it varies from region to region. You should always consult the planning officials, preferably confirmed in writing if planning permission is needed. We can provide a planning pack to help you with local authorities.
It is clearly important to discuss your plans with your neighbours. Relevant factors include environmental impact, access to the site, noise and visual effects. Overall, national planning policies support the development of small scale wind power.
Technical details
How does a wind turbine make electricity?
The wind turbine has three blades on the rotor which face away from the wind; the wind turns the blades round, this spins the shaft the rotor is mounted on, which connects to a generator. A generator produces electrical energy from mechanical energy.
What are wind turbines made of?
The wind turbine tower is made of galvanized steel. The blades are made of glass-fibre reinforced polyester. The finish in most models is matt, to reduce reflected light. The turbine is made from galvanized steel, stainless steel and some plastic components; everything is built to marine quality.
Can I build my own wind turbine?
It is entirely possible to build your own, but you may lose out on available grants. As with all technical and potentially dangerous equipment, most people should buy commercially manufactured and professionally tested machines. You could build your own base and we can provide instructions and a metal base, but the complexity of designing a properly strengthened tower is not to be under-estimated.
How is electricity connected?
The electrical output from the turbine needs to be converted to a standard UK mains supply, 230V AC. We provide an inverter which takes the electrical output from the turbine and produces 230V AC electricity. If you plan to connect to the Grid, then you need a different inverter.
How does the turbine face the wind?
Our turbines face away from the wind and are blown about, like a flag, so that they are always receiving the maximum wind.
How does the turbine cope with high winds?
Our turbines are designed to be used in any wind, even high winds (unlike large wind turbines which have to be feathered in high winds). The design of the rotor automatically twists the blade as the wind speed increases, so that the surface area of the blade reduces and hence limits the rotor speed. The turbine effectively protects itself. As the wind speed drops, the blades open back out. This means that you can get power from the turbine even in high winds.
Living with a wind turbine
What happens if there is no wind?
The turbine will produce power down to a wind speed of 2.5 m/s. Below that, no power will be generated. You will need an alternative source, such as batteries (which are charged when the turbine is operating) or a generator. If you have a Grid connected system, then you will draw power from the National Grid.
Are wind turbines noisy?
No. Our small wind turbines have been designed to be very quiet, by having direct drive systems to avoid gear box noise and to increase efficiency. Also, the aerodynamic efficiency of the blades means that the turbines are quiet in operation. In general, the wind itself makes more noise than a wind turbine. The noise increases with wind speed, but so does the noise of the wind.
Will small wind turbines affect birds?
Experience and careful monitoring by independent experts shows that birds are unlikely to be damaged by the moving blades of wind turbines. Bird strikes do happen, but rarely. Siting of the turbine is important to avoid nesting sites and migration paths. The rotor turns at a slow speed and the blades are painted black, which helps birds to spot the turbine. Birds are more likely to be affected by natural predators than wind turbines. The RSPB actively supports and promotes the use of wind power and does not object to wind turbines, because they see the greatest threat to birds is from climate change.
Will small wind turbines affect animals?
Not at all. There is no noise or emission that can affect animals. We have turbines installed on livestock and poultry farms, as well as equestrian centres.
What about lightning strikes?
Lightning strikes do occur and can cause damage to any structure raised from the ground. However, lightning protection is a well known practice and can be applied to wind turbines as for other equipment. On some turbine models, full protection of electrical circuits is installed at manufacture. Obviously, as with other elevated structures. protection against lightning is advisable if the turbine is installed in an area where lightning strikes are frequent. Insuring the turbine against lightning damage may be a wise precaution.
Does the turbine produce electricity during a power cut?
The turbine will need to disconnect from the Grid if there is a power cut, for safety reasons. Engineers may be working on repairing downed cables, so it is important that wind turbines don't feed power onto the lines.
Does the turbine interfere with electrical equipment or TV and radio?
The turbine will not interfere at all, with any electrical equipment or with radio, TV, mobile telephones etc. There is no radiation or electromagnetic fields produced at all.
Long term
Does the turbine need servicing?
The turbine requires an annual service, which must be done by trained staff. On some turbines, the tower needs to be lowered to get access to the turbine. On the larger turbines, there is a service platform just below the hub and
the maintenance work is done with the turbine in situ. The servicing is straightforward, requiring a number of bearings to be greased and slip-rings polished. The important part is an inspection of all parts for any wear and tear.
Will a wind turbine affect my house value?
There is currently no evidence in the UK showing that wind turbines adversely impact house prices. In fact, it will increase the value - as will solar thermal and solar PV panels
What is the life of a turbine?
The turbine has a design life of 25 years, providing the regular servicing is carried out.
Costs and grants
What are the warranty terms?
For all of our turbines, the standard warranty is for 5 years. Our terms are that the servicing must be carried out annually, by personnel approved by us.
How long will the turbine take to pay back?
This will depend on several factors.
- the extent of your wind resource will govern how effective the wind turbine is
- how much electricity you have to buy or how much you export
- whether you are eligible for any grants
You may achieve a payback period of 10 years and it is conceivable to do better than that.
Will I be able to get a grant?
It is impossible for us to say, but it should be possible for most people to get some sort of assistance, from Government funding or EU funding. There is much Government and commercial help to encourage investment in renewable resources.
Most of the Government effort is now directed at Feed-in Tariffs (FiT), which pays a higher rate for generated electricity than it costs for consumed electricity. The figures are attractive enough and are guaranteed, which makes it attractive for wind turbine owners to consider a loan or a mortgage. In addition, we provide our Flex 4 scheme. Visit our ‘Buying a turbine’ for more information on finance and the Flex 4 scheme.
How much can I get for the electricity I generate?
New Feed in Tariffs came into force in April 2010. Amounts payable have been announced by the Government (see our page on FiTs). There are costs to cover. The export meter has to be read and the companies charge for this. The meter costs between £75 and £200.
What rate of VAT applies?
VAT at the standard rate (currently 20%) is charged on wind turbine installations, the exception is when the electricity goes directly into a domestic property, rather than into the national grid, when the ‘reduced rate’ is charged (currently 5%).
