The economics of a wind farm depend entirely on the wind speed at your site. We have an excellent wind resource in the UK but not every site will be suitable. The first step you must take is to rule your project in or out by finding out if you have got enough wind.

The NOABL model is a database that holds the average wind speeds right across the UK. At this early stage of your site assessment this is accurate enough to rule your project in or out. You can access the NOABL model via the DBERR website for free.

The database will present you with wind speeds at three different heights, 10m, 25m and 45m. For a large scale turbine, the wind speed at 45m is the figure you are interested in. If this wind speed is 6.5 metres/second (m/s) or above then you have a site that could well become a viable wind energy project.

Beware - wind speeds can vary considerably over short distances! It may be possible for you to access additional data in order to improve on the NOABL information. You can purchase data from the Meteorological Office. This can be useful if you have a "met" station nearby.

Some organisations or institutions make regular recording of weather data, such as schools, colleges, universities or airfields. You can approach these organisations and ask if they are willing to share historical wind speed data with you or at least the long-term mean annual wind speed that they have measured at their site. Double-check the location of their monitoring equipment, what height they have been measuring the wind speed and the reliability of the monitoring equipment.

Eventually you will need to measure wind speed and direction over a twelve month period. This will require wind measurement equipment commonly known as anemometry equipment which will costs approximately £18k to install (in 2009) – an expense you don’t want to rush in to. This local wind data will then be correlated with historic data from the nearest Met Office station to give a long term predicted wind speed for the site. This will form the basis of the energy generation calculations used when financing the construction of the project.

High elevated sites, near the coast and with no obstructions such as buildings or trees usually provide the best wind speeds with low turbulence. However, low lying and inland sites are not excluded from wind energy development. Prevailing winds are usually from between the south and west.

You also will need good access to your site. Taking a series of photographs showing the view out from the proposed site around 360° provides a useful reference.