Wind power

Wind turbines catch the wind and turn to create electricity

Medium size wind turbines

Wind power has been used for centuries, of course, through windmills grinding corn. Nowadays wind turbines are mainly used to generate electricity and range in size from the giant 150m tall turbines being put out at sea, down to the much smaller designs used in rural properties.

How wind power works

Wind turbines use blades to catch the wind. When the wind blows the blades are forced round, driving a generator which produces electricity. The stronger the wind, the more electricity is produced. In fact, the output varies in relation to the cube of the wind-speed, so wind turbines are very much more effective in higher wind locations.

The most effective domestic-sized wind turbines are mast mounted units. These are free standing machines, typically 2.5kW to 6kW, which are usually erected on 10 to 25-metre masts in suitably exposed positions. Larger designs also exist all the way up to 3-5 megawatts.

Roof mounted designs around 1kW to 2kW have also been developed to be installed on the roof of a home where there is a suitable wind resource. However, please note that Ownergy is not currently offering these until better data is available on where they can be installed to provide a reliable output.

Most systems are connected to the grid which is important as it allows electricity to be ‘imported’ when the system isn’t producing enough power (i.e. on a windless day) and ‘exported’ when your system produces more electricity than you need. The exported surplus electricity is sold back to the grid at 3p/kwh under the Feed-In TariffS scheme.

Where it works best

Small domestic wind turbines work best in exposed locations, free from turbulence caused by trees, tall buildings, hills or other obstacles. Sites with an average windspeed of less than 5 metres per second are seldom suitable.

Small domestic wind systems normally require planning permission from your local authority, so you should check before you install a system.

How much energy it produces

The output of wind turbines is very dependent on the wind speed (as mentioned above) so the energy production is very site specific. Well located commercial onshore wind generators have a load factor around 25% which means they generate electricity at their rated level for roughly a quarter of the time. Consumer-scale systems are typically less than this, but we will only propose wind energy at sites where the output will be no less than 10-15%. In reality this means that most properties are not suitable for wind turbines.

Its maintenance requirements

The maintenance requirements depend on the design of the turbine. Some systems at this scale allow the mast to be lowered for servicing. Depending on the design, we typically recommend a service visit once a year to check on the performance of the system.

Tariff levels

… are shown here.