Wind Turbine
Read all about it here...

Windharvester has been decommissioned after many years of faithful service.

A new wind turbine will be arriving soon.

A few facts about the “Windharvester” turbine

Energy Production 2002 - 2015
The turbine was erected at the ERU Test Site in 1990, having been purchased as a small commercial machine from Windharvester Ltd. Other Windharvester turbines were installed at the Earth Balance Centre in Northumberland, and on remote communities such as Fair Isle in the Orkneys, and Foula in the Shetlands and Benbecula in the Western Isles.

By modern standards the RAL Windharvester turbine is small being rated at 45 kW (the turbines being installed at UK wind farms are rated at upto 5000 kW !), and having a hub height of 15.5 metres. The turbine has three blades (made of GRP (glass fibre reinforced polymer) which are fixed pitch (i.e. the blade angle is not varied during operation) and installed upwind of the tower – the blade diameter is 17 metres. The machine is turned (yawed) into the wind by a simple drive system using fantails.

The output power of a wind turbine depends on wind speed, and a typical power curve is shown below. With increasing wind speed, significant points on the curve are the cut-in wind speed (usually around 4 m/s, at which the wind turbine starts to generate), the rated wind speed (beyond which the output power is regulated to the rated power), and the cut-out wind speed (at which the wind turbine is shut down for safety and to avoid excessive stress).

Example Wind Turbine Power Curve (Click image for larger version)

The turbine, which is connected into the RAL electricity system, was used for many years in university-based R&D projects including wind/diesel systems, condition monitoring of wind turbines, electro-dynamic braking, advanced aerodynamics of wind turbine blades. It was overhauled and had many components replaced in 2001/2002. Since July 2002 it has largely been used to generate power into the RAL Grid.

Up until the end of 2011 the wind turbine has generated a total of 397,266 kWh over a 21-year period. This energy has been fed into the RAL grid, and is equivalent to the amount of electrical energy used by four typical UK households over this 21 year period.

However, the wind turbine does not generate power all time - as well as during periods of low wind speed, it is sometimes shut down for experimental instrumentation purposes, and of course for routine maintenance.