There are two windmills at middlewood. One supplies electricity to the study centre, and one to the farmhouse. They are of an unusual design made by a company called Proven, which has the blades on the downwind side of the mast. This allows the blades to bend away from the mast when the wind gets high, protecting them from damage, and the generator from being over spun. The way the system works is that the alternating current from the windmill's alternator is converted to DC and used to charge a battery bank. Then a device called an inverter runs from the 24V DC that the batteries put out, and uses this to generate mains current at 240V. This means that the study centre and farmhouse can use ordinary mains appliances.
The farmhouse has, in addition to the windmill, a set of solar electric panels, which turn sunlight into electricity. These charge the same battery bank as the farmhouse's windmill.
The farmhouse also has a solar heating panel. This consists of vacuum tubes containing dark painted copper fins, which have a liquid inside them. This liquid carries the heat from fins to the water circuit along the top of the panel, where the water is pre-heated to reduce the amount of gas needed to run the hot water and central heating.