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Winds of Change – UK
It has been calculated that Britain has the best potential in Europe for generating power from wind. In 2003, renewable energy sources in the UK accounted for around 3 per cent of the electricity generated, but wind contributed only 0.5 per cent, and mainly came from large wind farms. A Scottish entrepreneur is seeking to expand the role of wind energy through small wind turbines, hardly more intrusive than a satellite dish, which could be attached to most homes.
Windsave
| David Gordon, a successful entrepreneur, was outside a multi-storey block of flats in Glasgow in November 2001 when suddenly he had the idea. “I looked up at this with the wind swirling around and I had a flash of inspiration. What I needed to do was harness that wind and plug it into the building.” |
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Windsave turbine in Glasgow |
The idea has taken three years to develop from concept to prototype to finished product. In 2002, he formed Windsave Ltd to develop the domestic small wind turbine generator system using low wind speeds to create electricity, avoiding the use of batteries. Windsave has taken out global patents on the idea of capturing energy on site, and using it to supplement the household electricity supply.
The generator, developed by AEG to meet Windsave's design performance and size requirements, is the product of combined input from the AEG's induction motor technology centre and its permanent magnet motor expertise.
Windsave Turbines
The small and quiet turbines are pole-mounted to the wall of the house, generating enough power to run a TV and DVD player, computer, fridge/ freezer and several lights – producing up to 1 kilowatt of electricity to supplement the existing supply.
Unlike previous domestic wind generators, this system does not need batteries to store the electricity. A cable leads directly from the turbine into a control box where a sophisticated electronics ”Plug’n’Save” system smooths out the variable electricity created by the wind power and converts it to match the mains frequency. It is then fed into the household standard ring mains supply through a 13 amp plug. It supplements the existing mains supply, satisfying the base load of the house.
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| Plug’n’Save control box |
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The turbine can operate in wind speeds as low as 3 metres per second, but is most efficient at 12 m per second – common for much of the year across large parts of Britain. If the wind is not strong enough to convert usable wind power, the system monitors conditions until such time as the Plug’n’Save system can convert the wind energy to supply the electricity to the main supply. It goes into stand-by mode whenever the wind eases and automatically picks up again later on. Additionally the system has a safety shut-down braking mechanism to avoid over-run if the revolutions exceed 1060 rpm.
The specifications for the Windsave WS1000 system include:
- Plug-&-Save™ electronic conditioning system to fully synchronise the converted wind energy with the utility mains supply at 230 VAC 50 Hz.
- Three-bladed generator, rotating clockwise 'head into the wind', sweeping an area of 2.4 m2 (1.75 m diameter).
- Furling tail fin.
- Approximate total installed weight 25 kg, plus support pole and brackets (varied weight), standing between 1.5 and 3.75 m tall above roof/ wall interface line.
- Vibration: isolation pads used as necessary.
- Self contained metering (with remote monitor facility under development).
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| Layout of a Windsave installation |
Installation
The units are capable of being installed in any location where there is a reasonable amount of wind. Current laws allow windmills in many cases to be installed on rooftops without planning permission.
Typically wind turbines will be mounted on the gable end of buildings although they can be attached to the building side-walls, providing there is sufficient clearance space between the generator blade tips and the roof pitch line.
As the wind turbine system together with the support structure weighs almost 50 kg and is installed at height, it is vital that installers adopt safe systems of work (SSOW) at all times. Installations that are unsafe or cause problems to the properties to which they are attached have the potential to undermine confidence in the wind turbine market. The turbines are designed on ultimate loading of storm force conditions predicted over a 20 and 50 year occurrence. The system itself comes with a two-year warranty and 10 years’ expected working life.
Initial field trials of the Windsave wind turbine have proved so successful that British Gas has signed an agreement to undertake further trials with the view to market, install and maintain the product. British Gas plans to use its nationwide network of engineers to install the turbines. The company’s engineers will also be on hand to maintain the systems through an annual maintenance contract.
Recently the Windsave WS1000 system gained full “Clear Skies” accreditation. Clear Skies is an initiative promoted and funded in the UK by the Department of Trade & Industry to encourage the introduction of technologies that create renewable power to householders and the community. The funding programme will only recognise the system if it has been installed by a Clear Skies accredited installer. The programme will not recognise self-installed products. Clear Skies grants to householders for wind generator systems amount to £1000 per kWe installed up to a maximum of £5000. A Windsave installation at £1500 plus 5% VAT could therefore receive a £472.50 grant. In Scotland a similar grant scheme is operated under the Scottish Community and Householder Renewables Initiative (SCHRI) which provides upto 30% of the installed cost of a renewable measure up to £4,000.
Renewable Obligations Certificate (ROC)
ROCs are government-sponsored credits. They are available for generation of electricity from renewable sources. The Windsave system will qualify for these credits on the same basis as the large wind farms. Currently an annual ROC credit is worth approx £60 per megawatt. The Windsave system on average will produce sufficient electricity to claim one ROC. |
The units are nominally rated to produce 1 kilowatt-hour (1000 watts per hour) at a given wind speed of 12 metres per second. An average home needs around 2 kW for all its electricity needs, so the Windsave could provide over a third of the household’s electricity supply.
Possible Disadvantages
Wind power is a clean, renewable energy source. There are, however, some considerations to keep in mind when planning to install a wind power scheme.
Planning permission – Technically, planning permission is not required if turbines are sited below the highest point of houses, but some people may object to them being sited in particular areas.
Visual impact – Although small, if clustered together turbines could have a significant visual impact on their surroundings.
Location – The position and location of the wind turbine must be chosen carefully, as this is critical when optimising the potential wind energy capture from any site. The location of nearby tall buildings, high trees and other obstacles will disrupt the smooth flow of air around the building and care should therefore be taken to understand the prevailing winds and particular wind pattern of any site.
Noise – Wind rotors, gearboxes and generators create noise when operating. Each one generates around 45 decibels, which is the equivalent of a person talking in a normal voice. This would not normally constitute a problem, but if there were a number in a single neighbourhood their combined volume could be significant, so this needs to be considered when siting a machine.
Vibration – Resonance could be transmitted through the roof joists from the turbine to the home interior. Isolations pads should be used to minimise this problem.
Birds – turbines can kill birds, although the size of Windsave turbines makes this less of a problem than with large wind farms.
The Future
Dr Diana Montgomery, Head of Environment Strategy at British Gas, said, “Having a roof-top turbine means householders can save money and help do their bit for the environment – initial estimates show one unit could cut annual electricity bills by up to a third and reduce CO2 emissions by half a tonne per annum.”
With 26 million households in the UK, if only 10 per cent installed these turbines they would save a million tonnes of carbon dioxide per annum. Not only would they be making savings on their electricity bills, but they would also be supporting the environment.
There are currently 18,000 orders for the Windsave turbine, and David Gordon is optimistic about its future prospects. There are plans to list the company on the stock market during 2006 with a value of about £50 million, £10m of which will be used to fund international expansion.
Acknowledgements
Hands On would like to thank David Gordon, the head of Windsave Ltd, for his help in putting together this case study.
Further Information
Participating Organisations
Windsave Ltd
10 Lambhill Quadrant
Milnpark Trading Estate
Kinning Park
Glasgow G41 1SB
UK
Tel: +44 (0)141 420 7400
Fax: +44 (0) 141 420 7401
E-mail: info@windsave.com
Website: http://www.windsave.com/
Other Sources of Information
British Wind Energy Association
http://www.bwea.com/
Provides comprehensive information about wind energy, mostly wind farms, but they have produced a study on ‘Domestic roof-mounted wind turbines – the current state of art’: http://www.bwea.com/pdf/mid%20wales%20microwind.pdf
Clear Skies
http://www.clear-skies.org/
Clear Skies, funded by DTI and managed by BRE, aims to give householders and communities a chance to realise the benefits of renewable energy by providing grants and access to sources of advice.
Energy Savings Trust
http://www.est.org.uk/
This website has information about the Scottish Community and Householder Renewables Initiative (SCHRI) http://www.est.org.uk/schri/
The Energy Savings Trust encourages energy efficiency and the integration of renewable energy sources into the economic fabric of society. To achieve this
they promote the use of cleaner fuels for transport and better insulation and heating efficiency for buildings and homes and champion small-scale renewable energy, such as solar and wind power.
Resources
Practical Action Technical Information Service
Schumacher Centre for Technology & Development
Bourton Hall
Bourton-on-Dunsmore
Warwickshire CV23 9QZ
UK
Tel: +44 (0)1926 634462
Fax: +44 (0)1926 634401
Website: http://www.practicalaction.org/?id=technical_
information_service
ITDG Publishing
Schumacher Centre for Technology & Development
Bourton Hall
Bourton-on-Dunsmore
Warwickshire CV23 9QZ
UK
Tel: +44 (0)1926 634501
Fax: +44 (0)1926 634502
E-mail: marketing@itpubs.org.uk
Website: www.itdgpublishing.org
Related Hands On Case Studies
Winds of Change – Sri Lanka
http://www.handsontv.info/series2/its_a_gas_reports/
windsofchange_srilanka.html
Plug and Play – South Africa
http://www.handsontv.info/series2/its_a_gas_reports/
plugandplay_southafrica.html
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