Wind and watermills were a widely used renewable energy source. They became uneconomic with the development of fossil fuel engines. The recent and growing understanding of environmental issues however has led to an appreciation of the need to develop renewable energy sources.

In terms of energy production Sandhurst Windmill was built as a relatively powerful mill, able to drive four pairs of millstones. As an electricity generator it will be able to produce around 20kw. This will be more than adequate for the use of the dwelling.
The site has good wind characteristics. It is in a slightly elevated position and is in open countryside with no trees in close proximity. Kent has a high average wind speed.

The sail diameter will be 25 metres and the sails will rotate up to 16 revolutions per minute. The slow speed of rotation, which is comparable with traditional windmills, is approximately half the speed of modern wind turbines and the noise associated with modern turbines is not therefore generated.

Tunbridge Wells Borough Council has prepared an environmental strategy document. The strategy has a number of aims. One of the main aims is to ensure that local and global environment concerns are addressed. Energy used in buildings is a key objective. The council wants to reduce the use of non-renewable fuels, such as coal and oil, as far as possible by reducing the demand for energy, promoting energy efficiency and encouraging the use of other sources of energy. The strategy document states that the Council is able to affect how much energy is used in buildings through the granting of planning permission. It recommends that sustainable energy sources are encouraged and supported by the Council. The planning consent for the reconstruction of the windmill specifically supports its use as a renewable energy source.