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. Please call us for more information on any of these issues, we are here to help.
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 schools, higher education sites, community centres, farms and businesses and we offer a variety of wind turbine models. 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.
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 RenewableUK site. If ‘desk research’ identifies that you have a windy site, then we will perform a site survey for you to consider precise location, type of turbine and tower height.
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 wind turbines?
They need to be above ground at a safe height and in general, the higher the turbine, the higher the wind speed experienced by the turbine and the smoother the air.
How much space do I need for a turbine?
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 should positioned a distance of 10-20 times the height of the obstruction away from the obstruction.
You also need to consider the physical installation of the turbine and tower. Reasonable road access is required for the intallation of the turbine.
Do I need planning permission?
You will almost certainly require planning permission and this can take up to 6 months to obtain. Consult the planning officials, preferably confirmed in writing if planning permission is needed. We can help you with progressing planning permission with your local authority.
It is important to discuss your plans with your neighbours. Relevant factors include environmental impact, access to the site, noise and visual effects. Planning policies vary by council.
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 is three-phase, at 415V AC. The EWP E-3120 is a directly coupled turbine, with the generator running at 1,500 rpm, and the generator is directly connected to the Grid through an automatic control system, without any conversion. Power will only be connected if the Grid conditions allow it.
How does the turbine face the wind?
Our turbines face away from the wind, they are known as downwind turbines, and they are blown about, like a flag, so that they are always receiving the maximum wind.
The turbine monitors the direction that the wind is coming from and rotates itself around to ensure it is always facing in the right direction.
How does the turbine cope with high winds?
Our turbines are designed to be used in all wind conditions, excluding severe winds when the safety function will automatically close the turbine down until the winds have subsided to safe levels - disk brakes stop the turbine turning and the turbine rotates to minimise the wind force on the blades. The design of the blade uses a technique called 'Aerodynamic stalling'
which sheds wind in excessive wind conditions in order to protect the turbine from damage. The turbine effectively protects itself. It also 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?
If there is no wind then 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. 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. 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. 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?
For safety reasons the turbine will need to disconnect from the Grid if there is a power cut. Engineers may be working on repairing downed cables, so it is important that wind turbines don't feed power onto the lines. This is done automatically as part of the turbine's control system.
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 a service every 5000 hours, which must be done by trained staff. 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 and includes 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 property 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 30 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 5-10 years and it could well be less.
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 ‘Finance’ page 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%).
