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Small Wind Technologies

Building-integrated and stand-alone systems

There are two basic systems available for using wind turbines to generate electricity - stand-alone or grid-connected. Wind turbine design can be either the more common horizontal axis type or vertical axis design. The turbine design and size to suit your site best is very dependent on your individual circumstances.

Small scale wind turbines vary in size with a range of models available, from less than 100 watts (W) up to 50 kilowatts (kW). Smaller, less than 100W, microturbines, are often used to charge 12 volt (V) or 24V batteries, for use on stand-alone systems. Turbines ranging from 0.6kW to 50kW can be used to provide electricity generation for individual houses and businesses, with rooftop models varying from 0.5kW to 2.5kW in size.

Stand-alone systems

Ampair wind turbine

Small wind turbines have traditionally been used to generate electricity for charging batteries to run small electrical applications, often in remote locations where it is expensive or not physically possible to connect to a mains power supply. Such examples include rural farms, island communities, boats and caravans. Typical applications are electric livestock fencing, small electric pumps, lighting or any kind of small electronic system needed to control or monitor remote equipment, including security systems.

Grid-connected systems

Proven turbine

Here the output of the wind turbine is directly connected to the existing mains electricity supply. This type of system can be used both for individual wind turbines and for wind farms exporting electricity to the electricity network. A grid-connected wind turbine can be a good proposition if your consumption of electricity is high. The energy produced by the turbine can be used to reduce the energy taken from the grid, and for claiming Renewables Obligation Certificates (ROC)s, which is the only realistically achieved benefit for generators less than 10 kW installed capacity, however some supply companies may be able to help if you are able to export a significant amount of your generation. If you are significantly exporting generation with an installed capacity greater than 10kW then it is quite possible to get a good price for both onsite and exported generation. The value of avoided electricity purchases is generally significantly higher than the value that can be obtained from exporting power to the grid. This is particularly relevant if you are a business consumer of electricity as such onsite generation will qualify you for exemption from the Climate Change Levy.

When a wind turbine connection to the mains supply is made, it has to be approved by your local electricity distribution company. They will insist on the connection being to a high technical standard and therefore the cost of incorporating power import and export metering and approved electrical protection equipment can be high. They may also limit the size of the wind turbine that may be connected in a particular area depending on the loading of the electrical distribution system in the vicinity. For small wind turbines, the cost of grid connection can be a substantial part of the total project cost.

Building-mounted turbines

Swift rooftop turbine

Building-mounted small wind turbines are a new breed in the development of small scale wind. In this case, the wind turbine is directly installed on to a building, usually on the rooftop. Designs of such systems vary from manufacturer to manufacturer and include both vertical and horizontal axis machines.

Export & Supply

To get extra value from your installation you can sign either an export arrangement or a buy & sell back arrangement with a complying electricity supply company. These agreements may require that you get accredited for the various benefits of renewable generation such as ROCs, LECs, and REGOs, and so to claim these benefits you must fit an Ofgem accredited total generation meter, ask your green supply company for more information.

Swift wind turbine

Installing a Small Wind Turbine - in a nut shell

1. Get a reliable estimate of the wind speed at the proposed site. Turbine manufacturers should be prepared to help. The generator must get acceptance for connection to the electricity distribution network. (if applicable).

2. Mount the turbine on as high a tower as possible and well clear of obstructions, but do not go to extremes. Easy access will be required for erection, and foundations for the tower may be needed depending on the size and tower type. It is also important to ensure that the wind turbine can be easily lowered for inspection and maintenance.

3. Try to have a clear, smooth fetch to the prevailing wind, e.g. over open water, smooth ground or on a smooth hill.

4. Use cable of adequate current carrying capacity (check with the turbine supplier. This is particularly important for low voltage machines). Cable costs can be substantial.

5. Consult your local council as to whether you need planning permission. You should try to minimise the environmental impact of the turbine, and it will be helpful to inform your neighbours of your plans at an early stage.

6. For larger machines you may have to pay rates. This can make a big difference to the economics of the installation, again you should find this out by consulting your local council. Once the machine is under construction, ask your chosen supply company whether they need you to be accredited for ROCs, LECs, & REGOs and what type of onsite and/or export metering they require you to have (if applicable).

Further information