Technical and Maintenance.

 

Wind turbines use the wind's lift forces to rotate aerodynamic blades that turn a rotor which creates electricity. In the UK we have 40% of Europe's total wind energy but it's still largely untapped and only 0.5% of our electricity requirements are currently generated by wind power. Most small wind turbines generate direct current (DC) electricity. Systems that are not connected to the national grid require battery storage and an inverter to convert DC electricity to AC (alternating current - mains electricity). Wind systems can also be connected to the national electricity grid. A special inverter and controller converts DC electricity to AC at a quality and standard acceptable to the grid. No battery storage is required. Any unused or excess electricity may be able to be exported to the grid and sold to the local electricity supply company.

There are two types of wind turbines:

• Mast mounted - which are free standing and located near the building(s) that will be using the electricity
• Roof mounted - which can be installed on house roofs and other buildings

 

Individual turbines vary in size and power output from afew hundred watts to two or three megawatts (as a guide, a typical domestic system would be 1 - 6 kilowatts). Uses range from very small turbines supplying energy for battery charging systems (e.g. on boats or in homes), to turbines on wind farms supplying electricity to the grid.

You should consider the following issues if you're thinking about small scale wind. An accredited installer will be able to provide more detailed advice.

 

• Wind speed increases with height so it's best to have the turbine high on a mast or tower
• Generally speaking the ideal site is a smooth top hill with a flat, clear exposure, free from excessive turbulence and obstructions such as large trees, houses or other buildings
• Small scale wind power is particularly suitable for remote off grid locations where conventional methods of supply are expensive or impractical. Small-scale building-integrated wind turbines suitable for urban locations are also available to install in homes and other buildings.

Please note that the electricity generated at any one time by a wind turbine is highly dependent on the speed and direction of the wind. The windspeed itself is dependent on a number of factors, such as location within the UK, height of the turbine above ground level and nearby obstructions. Ideally, you should undertake a professional assessment of the local windspeed for a full year at the exact location where you plan to install a turbine before proceeding. In practice, this may be difficult, expensive and time consuming to undertake. Therefore we recommend that, if you are considering a domestic building mounted installation and electricity generation is your main motivation, then you only consider a wind turbine under the following circumstances:

• The local annual average windspeed is 3.5 m/s or more. An approximate figure for your location can be checked on the BERR website
• There are no significant nearby obstacles such as buildings, trees or hills that are likely to reduce the windspeed or increase turbulence

Issues to be taken into consideration include:

• The average wind speed at the site. Currently a domestic wind turbine will start generating electricity at a cut-in wind speed (approximately 2.0 m/s), though to be commercially viable a long-term annual average wind speed of 3.5 m/s should be sought
• The uneven and turbulent wind patterns that occur near buildings and other obstacles.

• The need for planning consent. The best practice for a developer is to speak to the local planning authority at the earliest possible opportunity to see if there are objections to the proposal which cannot be negotiated. However, the planning office may also indicate key issues of concern from which a judgement can be made on how to deal with the proposal in terms of the design, location, size and scale of the project. The potential visual impact on important public viewpoints and on local ecology should also be assessed.
• Any landscape designates (such as AONB or SSSI) and Conservation Areas.
• The need to maintain adequate access for maintenance and initial installation.
• Possible noise from the turbines (although modern turbines without gearboxes are quiet and are said to be drowned out by a passing car). Many London areas have 24-hour background noise which can mask any noise from a wind turbine. For more information see the BWEA web page
• The available space for a turbine, as they must be placed a minimum distance from residential and school buildings due to noise, reflected light and shadow flicker, which varies according to their height.
• Some turbine blades come in different colours. The colour could be chosen to enhance the appearance of the turbine or make it as inconspicuous as possible (if this was the desired outcome)

Maintenance Requirements

There are very few maintenance requirements - a service check every couple of years would be advisable- Enviko would undertake this as part of its ongoing provision of after-care services. A wind turbine typically lasts 20-25 years.

Additional Benefits of the Technology

• This is one of the more cost effective of the available renewable technologies
• There could be significant green marketing opportunities

 

 

Please feel free to get in contact with us by email or call 0845 189 9894 to discuss any of your requirements.