Energy Saving Trust
North East Renewable Energy Directory
Grass - technologies
NERA - North East Renewables Alliance
Factors to consider

Technical feasibility check

  • Do you have a ground or roof site for the micro-wind turbine that is exposed to a steady, consistent wind?
  • Is the site free from wind-shading or sources of turbulence? E.g. caused by other buildings, trees etc.
  • For building-mounted micro-wind turbines, is your roof strong enough to hold the turbine? (advice should be sought from a structural engineer)

Technical suitability

The recent generation of micro-wind turbines on the market have had very bad press.  The main mistake was to suggest that they can be installed everywhere. This has proved not to be the case due to the relatively small amounts of power available at low or turbulent wind speeds, and the technology used where turbines were connected directly to inverters. Grid inverters require 3 minutes of smooth power before letting that power into the mains. Micro-wind turbines were unable to do this in all but the best wind situations.

Lessons have now been learnt and the next generation are coming with batteries so the turbine can charge a battery and then the battery can power an inverter and so provide smooth power.

A steady consistent wind is necessary for a micro-wind turbine to work efficiently. A south-west facing coastal, upland or exposed flatland would be the ideal location for a wind turbine. Failing this, the wind turbine needs to be positioned as high as possible- normally at roof level for building-mounted turbines. In America where turbines have been used for off-grid electricity for most of the last century, it is known that a taller tower is always much more important than a bigger turbine.

In order to determine the average wind speed for your proposed site, you can look at the Department for Business, Enterprise and Regulatory Reform’s (BERR) Windspeed Database at www.berr.gov.uk/energy/sources/renewables/explained/wind/windspeed-database/page27708.html  - the database can also be accessed via the British Wind Energy Association website ( www.bwea.com).

Wind shading is as critical to turbines as light shading is to PV. Any wind shading will reduce your harvest. Therefore you need to consider the proximity of trees and other buildings which may shelter the turbine from the prevailing wind. Ground-mounted turbines may be more suited to rural environments where there is sufficient space to mount the turbines away from wind shading from buildings.

Rotors for domestic scale turbines are typically around 1.75 – 2m in diameter. Building-mounted turbines require firm fixing because of the large forces that will be generated due to wind loading and vibration. You may need to consult a structural engineer to check the suitability of your home for supporting a wind turbine.

Any excess power generated by you micro-wind turbine can be exported to the grid (see ‘additional information’ below).

Nontechnical constraints

Turbine erection can generate strong views. It is necessary to consider environmental considerations, access to the site, noise and visual effect (see section on planning permission below for further information).

Export tariff

Most (but not all) electricity suppliers will agree to purchase your exported electricity. To achieve credit for the electricity that you are generating on windy days it is essential that a good export tariff is made use of – tariff’s vary between suppliers so shop around! To enable you to export electricity you need to have a ‘smart’ electricity meter that is able to measure the electricity that you export to the grid. Old style electricity meters with wheels can run backwards when electricity is being exported, and therefore provide net metering (though this practice is not strictly legal).
 
Heritage issues

If you are intending to carry out works to improve energy efficiency to a listed building or a building in a conservation area first check with the local planning authority whether any consent may be required. Alterations that affect the external or internal appearance (in the case of listed buildings) and character including any materials, details and finishes may well require consent. Local planning authority conservation officers can also advise on the balance between historic building conservation and energy efficiency in historic buildings. Large numbers of traditional buildings are not listed or situated in any designated areas. Many of these will nevertheless have features of some historic interest. This means that any adaptations made to improve energy efficiency need to take account of the traditional performance of the building fabric and its compatibility with the new materials that are being proposed

Find your local planning authority at:
http://www.planningportal.gov.uk/wps/portal/genpub_LocalInformation?docRef=1103046453478&scope=202&langid=0.
Source: www.planningportal.gov.uk/england/genpub/en/1115315126253.html
For more information visit the English Heritage web-site linked to improving the energy performance of listed buildings.  www.climatechangeandyourhome.org.uk
See also English Heritage’s guide to Micro wind generation and traditional buildings, available at: http://www.helm.org.uk/upload/pdf/69945-MicroWind1.pdf

Installation considerations

Installation requires working at height skills and safety procedures. Towers for turbines will also require input from structural engineers.

Maintenance considerations

Service checks are required every few years to ensure turbine(s) is working efficiently. Checks should also be made on the mountings and the adjacent masonry to ensure that the unit remains firmly fixed to the building.

Lifetime

There is little definitive data on service life because the technology is relatively new. The expectation is that turbines will last a minimum of 10 years and up to 20 years depending on the local conditions. For example, life expectancy may be shorter in coastal environments. For battery storage systems, typical battery life is around 6-10 years, depending on the type, so batteries may have to be replaced at some point in the system's life.

Questions to ask suppliers

  • Is your product certified under the Microgeneration Certification Scheme (MCS)?
    The MCS underpins the Low Carbon Buildings Programme, which provides grants for installing renewable energy technologies. MCS is designed to evaluate products and installers against robust criteria for microgeneration technologies. Visit this website to find an MCS approved product: www.greenbooklive.com/page.jsp?id=131
  • Does your product work by charging batteries or does it deliver grid-connected mains voltage power via an inverter?
  • Does your product meet the British Wind Energy Association Small Wind Turbine Performance and Safety Standard (29 Feb 2008)? Find information at: http://www.bwea.com/small/standard.html

Questions to ask installers

If you would like to be included in this directory please contact us here:
North East Renewables, 18B Manor Way, Belasis Hall Technology Park, Billingham, TS23 4HN Tel: 01642 373028 Email: advice@n-e-renewables.co.uk"
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