Small Wind FAQs
1. What are wind turbines made of?
Wind turbine towers are generally made of steel. The blades are made of glass-fibre reinforced polyester or wood-epoxy. The finish in most models is matt, to reduce reflected light.
2. How much of the time do wind turbines produce electricity?
A modern wind turbine produces electricity 70-85% of the time, generating different outputs at different times depending on wind speed.
3. Are wind turbines noisy?
The majority of modern small wind turbines have been designed to be very quiet, for instance by having direct drive systems to avoid gear box noise and increase efficiency. In general, the wind itself makes more noise than a wind turbine. It is most unlikely that any noise will be heard from small wind turbines at more than 50 metres.
4. Are there any problems with low frequency noise?
Small wind turbines do not cause low frequency noise issues.
5. Do wind turbines affect radar systems or TV reception?
Small wind turbines are unlikely to have any detrimental effects on aviation and associated radar or navigation systems. In general, turbines with small diameters are unlikely to have effects on television and radio reception. If this occurs it is likely to be highly localised and technically easy to overcome. It is also unlikely that building-mounted wind turbines will affect either mobile phone reception or fixed radio or microwave communications links.
6. Will small wind turbines have a 'flicker' from the turbine blades?
Potentially, sunlight passing through moving blades and into small apertures in buildings can cause a flickering effect on the other side of the aperture when this aligns with the sun and turbine. The configurations necessary for this to happen are very rare and confined broadly to larger turbines. It is best practice at the site selection stage to consider any possibility of the shadow from the wind turbine causing flicker at a nearby property at a given time of the year. It is normally possible to avoid this problem. Glare from the blades is also unlikely, especially as the coatings used on modern turbines have been selected to minimise reflection.
7. Do these turbines affect epilepsy sufferers?
Although there have been investigations into whether the rare phenomenon of shadow flicker (see above) may trigger seizures in sufferers of epilepsy, there is no link between small wind turbines and epilepsy.
8. 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. More information about this can be found from BWEA's Best Practice Guidelines and the Royal Society for the Protection of Birds, which views “climate change as the most serious long-term threat to wildlife in the UK and globally and, therefore, RSPB supports the Government's target to source 15% of electricity from renewables by 2015... wind power has the greatest potential to make a significant difference in the UK in the coming decade... The available evidence suggests that appropriately positioned wind farms do not pose a significant hazard for birds."
9. Do turbines affect animals?
Turbines do not adversely affect animals at all. Installations exist on farms, nature centres and equestrian centres with no problems for the animals.
10. What about lightning strikes?
Lightning strikes 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 if really felt to be required.
11. How long will a turbine take to pay back?
Paybacks will depend on several factors. The main ones are your wind resource and size of turbine, what you pay/get paid for your electricity and whether you get any sort of grants for the project. You should also factor in maintenance costs and long-term price increases (above inflation) for electricity.
12. What is the life of a turbine?
Free-standing turbines typically have a design life of 20-25 years.
13. How far away can I mount the turbine from a building?
Turbines can be mounted as close as 20m or as far away as 500m depending on the turbine type and the cable used to bring the electricity back to the building. The latter point is important as the further away the turbine is, the bigger the cable required to minimise transmission losses and this adds to cost.
14. What space do I need to erect a turbine?
Each turbine and tilt-up tower combination requires its own “footprint” on the ground. As a rough guide taking the tower height and multiplying it by 2.5 will give you an approximate horizontal length required on the ground. The width would be the rotor diameter plus 2 metres to allow enough space for raising and lowering. Guyed towers require more space.
15. Will the turbine affect my own or my neighbour's property price?
Chances are that it will add value to your property. There is no evidence of wind turbines, large or small, affecting property prices adversely in the long term.
16. Do I need three-phase electricity supply to host a turbine?
To extract full value from a turbine rated at 5 kW or over, it is preferable, but not essential, to have a three-phase electricity supply. Below 5 kW, it is not necessary and the power generated can be handled comfortably by a single phase connection.
17. Can a turbine be re-sited?
Yes, provided the new site is suitable. Costs will be incurred to dismantle the turbine, transport it to the new site and re-install it. An estimate of these costs can only be prepared after a survey of the old and new sites.
18. Why don't they make turbines that look like old fashioned windmills?
The old-fashioned windmill is viewed with nostalgia, and some people prefer the look of them to that of their modern counterparts. However, just because wind turbines are modern, it doesn't mean they won't look just as good over time.
A modern wind turbine is broadly speaking an improved and specialised windmill. Every aspect of their design has been optimised for generating electricity, making them far more efficient for that purpose than the old-style windmills, which were designed for mechanical applications. To make them look more old-fashioned would result in prohibitively expensive electricity.