How do wind turbines actually work?

Many households and small businesses are turning to renewable energy solutions in order to lower electricity bills and help the UK lower carbon emissions. There are a number of options available, with solar PV panels and ground source heat pumps growing in popularity throughout Britain. However the UK is the windiest country in Europe, and wind power is the natural choice for many individuals considering an investment in green technology.

The UK government already generates significant energy from offshore and onshore wind farms, but generally businesses, farms and country estates are not situated in typical high wind speed areas. For sites in moderate wind speeds, most villages and small towns, a small domestic wind turbine could significantly lower energy bills while owners could benefit additionally from the government's Feed-In Tariff scheme.

Small, domestic wind turbines operate in a similar way to the giant wind turbines in large wind farms. Large rotor blades rotate around a central hub, which is connected to a gear box that drives a generator. These are located inside what is known as the nacelle, which can be seen behind the rotating blades. All electrical components are housed inside the nacelle which sits on top of either a cylindrical tower or a lattice tower, depending on the manufacturer. This type of turbine is known as ‘horizontal axis'.

Tower height can range from 10m to 30m, with 18m being the most popular for small businesses, farms and country estates. Tower height is important to performance: there is a 10% difference in energy production between a 15m tower and an 18m tower. It is always recommended that anyone considering a wind turbine contacts the local authority before installation as some councils impose height limits depending on site location.

Site location is another factor that is crucial to the performance of a small wind turbine. It is important to consider the surrounding area and how the landscape could affect wind flow. A domestic wind turbine will operate best when there are very few obstacles in the surrounding area. An exposed location without many buildings, trees or hills is the perfect area for a wind turbine. It is possible to successfully install a wind turbine with good results in areas that contain wind flow obstructions, however results will not be quite as impressive.

Wind technology is improving all the time and with a growing number of suppliers in the market the costs of installing a small wind turbine have fallen dramatically. The UK government has set a number of energy targets to achieve over the next decade, and expects a large increase in domestic renewable energy installations throughout the country.

The introduction of the UK's Feed-In Tariff allows owners of wind turbines to benefit from a payment for all clean energy generated. For example if a small domestic wind turbine with a rating of 11kW was installed on a site then the owner would benefit from 26.7p per kWh generated. On average an 11kW turbine would be likely to generate between 15,000 and 40,000 kWh per year, depending on wind speed (for example the difference between an average wind speed of 4.5 m/s and 6.5 m/s). In order to be eligible for the tariff the manufacturer and product must be listed on the Microgeneration Certification Scheme's list of accredited suppliers.

It is important to understand how small wind turbines work and consider their suitability on a site by site basis. However there are a number of benefits to owning a small wind turbine, and after the initial investment there is the potential to earn significantly in a number of different ways.