FAQ

A summary of most Frequently Asked Questions and their answers.

This list is an adapted version of the FAQ of the British Wind Energy Association, the
original can be found here.

Have your own turbine

  1. Can I have my own wind turbine?
  2. How do I find out if my site is windy enough?
  3. How does a wind turbine make electricity?

Turbine details

  1. What size turbine will I need?
  2. How tall are small wind turbines?
  3. How much space do I need for a turbine?
  4. Do I need planning permission?
  5. What are wind turbines made of?
  6. Can I build my own wind turbine?

Issues to consider

  1. Are wind turbines noisy?
  2. Do wind turbines affect radar systems or TV reception?
  3. Will small wind turbines have a 'flicker' from the turbine blades?
  4. Will small wind turbines affect birds?
  5. What about lightning strikes?

Electricity generation

  1. Can I use my turbine for heating?
  2. Can I connect my turbine to the grid?
  3. How much of the time do wind turbines produce electricity?
  4. What happens when the wind stops blowing?

Costs and funding

  1. Isn't it cheaper to save electricity?

Turbine lifetime

  1. How do I look after my wind turbine?
  2. How long do wind turbines last?
  3. Can the turbine be re-sited?
  1. Can I have my own wind turbine?

    Small wind turbines are ideal for householders, communities and small businesses to use for on-site energy generation. Your individual site specifics (such as location, wind speed and local landscape) will eventually determine the best turbine type and size for your case.

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  2. How do I find out if my site is windy enough?

    BWEA has a UK Wind Speed Database, which tells you the average wind speed in your
    area. The actual wind speed at your site will be influenced by the local topography and
    any nearby obstructions such as trees or other buildings. Wind movement around
    buildings themselves is very fickle, so take expert advise is machines are fixed to buildings
    rather than free standing on a tower or mast. A site with an average wind speed of 4-5
    meters per second is generally sufficient enough to make installing a small wind turbine
    worthwhile.

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  3. How does a wind turbine make electricity?

    Most wind turbines have three blades which face into the wind; the wind turns the blades
    round, this spins the shaft, which connects to a generator. A generator produces electrical
    energy from mechanical energy. See more information here.

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  4. What size turbine will I need?

    To find out how much a wind turbine produces, go to our calculations page to see energy
    production. Note however, that the generation from a wind turbine and the demand in a
    house are not coincident. If the wind turbine is connected to your side of the utility meter,
    you will use all the wind power available to meet your demand. When the wind
    generated power is greater than your demand, the excess is exported to your local
    network. You are permitted to sell that excess to a Supplier under terms arranged with
    that Supplier. Export metering measurement will be needed, but this need not be at short
    intervals (e.g. half hourly) and may be annual. However, generally, the meter reading
    charge is large, ~ £50, and so at least about 5,000 kWh/year of exported electricity will be
    expected before earning sufficient to cover more than the meter reading charge.

    The table below can be used as a guideline for choosing the right model. A 'normal'
    household will use about 4,000 kWh annually. A heavy user might have a heat pump
    and have an annual consumption of 6,000 to 8,000 kWh. Normal wind speeds would
    be around 5.5 m/s on average, with high wind speeds around 6.5 m/s.

    Purpose Wind Speed Turbine
    Contribution to saving energy any Espada or Passaat
    Self-sufficient normal household high Passaat
    Self-sufficient normal household normal Montana
    Self-sufficient high electricity user high Montana
    Self-sufficient high electricity user normal Alize
    Energy saving for a small industry or farmer any Alize

     

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  5. How tall are small wind turbines?

    Tower height varies according to wind turbine models, but generally range from 6 to 24 meters. In general, the higher the tower, the higher the average wind speed that the turbine will experience and the smoother the wind. The rotor diameter of small wind turbines ranges from 2.0 to 7 meters depending on the type of a model.

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  6. How much space do I need for a turbine?

    Ideally, stand-alone 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 in the immediate 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 meters of the tower heights. See also our fact sheet on siting a wind turbine.

    Rooftop-mounting turbines is not something we generally recommend. It is fairly difficult finding a place on a roof that is strong enough to withstand the forces and has a good wind. Local turbulent airflow around the building, which causes reduction in generated output and could damage the turbine, must be considered as well. In general, the less turbulent and varying the wind, the better the wind power generation.

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  7. Do I need planning permission?

    Small wind energy installations may require planning permission and you should always consult the planning officials, preferably confirmed in writing if this is needed. It is clearly good manners to discuss your plans and aspirations 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 energy.

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  8. What are wind turbines made of?

    Our wind turbines are made of stainless steel, hot sink dipped steel and plastics, so they
    won.t rust. The blades are made of carbon-fibre reinforced-epoxy. Check our technical details page for more information.

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  9. Can I build my own wind turbine?

    There is a very good book on this subject, 'Wind Power Workshop' by Hugh Piggott, available from the Centre for Alternative Technology. For a brief idea of what is involved see how to build your own wind turbine. However, as with all technical and potentially dangerous equipment, most people should buy commercially manufactures and professionally tested machines.

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  10. Are wind turbines noisy?

    Our small wind turbines have been designed to be very quiet, for instance by having direct
    drive systems to avoid gear box noise and to increase efficiency. In general, the wind itself makes more noise than a wind turbine. It is most unlikely that any noise from small wind turbines will be heard at more than 30 m.

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  11. 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.

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  12. Will small wind turbines have a 'flicker' from the turbine blades?

    Potentially, sunlight passing through moving blades can cause a flickering effect in 'line of sight' directions. The possibility of the shadow from the wind turbine causing flicker should be considered at the site selection stage. It is normally possible to avoid this problem. Reflections from the blades are unlikely, especially as the coatings used on modern turbines have been selected to minimise reflection.

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  13. 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 Best Practice Guidelines and the Royal Society for the Protection of Birds, whose view is that "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."

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  14. What about lightning strikes?

    In our over 25 years of manufacturing wind turbines, we have had one occasion of a turbines which was damaged by lightning. Considering the costs of protecting the turbines against strikes, we prefer not to do so.

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  15. Can I use my turbine for heating?

    The simple answer is yes, small wind turbines can be used for direct heating, e.g water heating as well as for battery charging and they are also ideal in remote off-grid locations. However, the energy required to heat a building is usually significantly more than the energy used in electricity, so a much larger turbine would be needed for building heat. Direct heating is only done with excess energy, for example when the batteries (is used) are full. Small wind turbines are very effective for powering a heat pump, which can heat your house.

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  16. Can I connect my turbine to the grid?

    Small wind turbines can be connected to the local electricity network and the total electricity they generate is eligible for Renewables Obligation Certificates (ROCs) under the Renewables Obligation (i.e ROC income can be obtained from both the electricity you use on site and that you export). The value of a ROC is now (2006) about 4.5 p/kWh. When a wind turbine connection to the mains supply is made, it has to be approved by your local electricity distribution utility. This company will require the connection to be of a satisfactory technical standard. Therefore the cost of incorporating power import and export metering and approved electrical protection equipment may be a significant proportion of the total cost, i.e. perhaps about 10% or more. The company may also limit the electrical capacity of the wind turbine that may be connected to a particular distribution line, depending on the loading of the electrical distribution system in the vicinity.

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  17. How much of the time do wind turbines produce electricity?

    A modern wind turbine produces electricity 70-85% of the time, but it generates different outputs dependent on wind speed. Over the course of a year, a small wind turbine in the UK will generate about 20% to 30% of the amount it would generate in a constant strong wind. This is known as its 'load factor' (or 'capacity factor'). The turbine itself has usually at least 97% mechanical availability and generates with 95% mechanical to electrical efficiency, so the limited output is overwhelmingly associated with lack of wind The load factor of conventional UK thermal power stations is on average 50%, and the mechanical to electrical efficiency is between 30% and 50% depending on the type of plant.

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  18. What happens when the wind stops blowing?

    When the wind stops blowing, electricity continues to be provided by other forms of generation in an isolated system (e.g. batteries, diesel generator), and by the grid in a grid-connected system. UK electricity generation is now overwhelmingly from large power stations, and so the system has to cope when one of these large plants goes out of action. Consequently, it is possible to have at least 10% to 20% of the country's electrical demand met by intermittent energy sources such as wind energy, without having to make any significant changes to the way the system operates.

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  19. Isn't it cheaper to save electricity?

    Since most of us are not fully efficient in using energy, it is almost certainly cheaper to reduce electricity consumption than to buy it or generate oneself. The latest information on how much it costs to save electricity is available from the Energy Savings Trust. Nevertheless, electricity generation is necessary. Therefore, to combat climate change and to have security, it is essential both to increase the proportion of renewable energy and also to have energy efficiency.

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  20. How do I look after my wind turbine?

    The maintenance required for small wind turbines is likely to be minimal. Our turbines are designed for over 20 years life time. Bearings are greased for life and sealed so you don't have to grease them annually. But an annual check is likely to be required and can be performed by yourself or your dealer.

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  21. How long do wind turbines last?

    Our wind turbines typically lasts around 20 years. This is not theory, because our firm is already in business for over 30 years and we have had clients that came back after 21 years, to buy their second turbine because the first one was not performing well anymore.

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  22. Can the 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.

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