What is the best site for a turbine?

The ideal site for a wind turbine is on the top of a smooth, rounded and exposed hill - clear of any turbulence or losses created from obstructions such as trees, buildings or cliffs. In practice, such sites may not be available. It is important in selecting a site to consider that the power available to a turbine is related to the wind speed cubed - even a small increase in wind can give a large increase in output. Wind speed increases with height, hence an increase in tower height can yield a significant improvement in turbine performance. To maximise output and minimise the effects of turbulence, the turbine should be mounted away from and above obstructions such as buildings or trees. A common rule of thumb is that the turbine should be placed away from an obstacle at a distance of at least 10 times the obstacle's height, or mounted on a tower over 2 times the height of the obstacle. The key point is to keep the turbine clear of large obstacles, particularly in the path of the prevailing wind. This should take account of possible future obstructions such as tree growth. Sundog energy site assessment form includes diagrams that can help in identifying suitable sites.