The site requires you register, but results can then be saved.
CT say the Wind Yield Estimation Tool enables you to estimate the local annual mean wind speed at your chosen location in the UK and the annual yield and carbon savings of a small wind turbine. The tool is intended for guidance purposes only.
The calculation methodology has been developed by the Met Office and Entec following a research project commissioned by the Carbon Trust.
In order to make a calculation you will need details of:
a. The place under consideration for installation of a turbine, including the specific location (defined by grid reference* or postcode) and general character (e.g rural, woodland, etc)
b. The turbine it is planned to install, including its height (rotor mid-height) and power curve. Manufacturers should supply this in their literature. In the absence of power curve data, it is possible to estimate the local annual mean wind speed but it is not possible to obtain an estimate of energy yield or carbon savings).
The data entered can be saved for review or editing at a later date.
* UK grid references can be found at the Multimap site.