Landowners & farmers:

Turbine installation

What is involved?
The installation of an average size wind farm (30-40 turbines) takes approximately six months. The actual construction process is a series of distinct activities that can be planned in association with the landowner so as to minimise disruption to farming activities. Once the turbines are in place, normal farming can go on around them. There is no requirement to fence off the towers and the rotating blades are well clear of the ground.

Tower Base
The turbines can be built on concrete slab foundations, via mono-pile or secured with rock anchors. The largest area occupied by the foundations is in the order of 14x14 m by 2 m deep. Foundations are buried below normal ploughing depth, at least 1m below ground surface. Consequently, arable farming can continue up to the base of the 4 metre diameter towers. The turbines are connected together by underground cables, which again are buried below ploughing depth, approximately 1m below ground surface. Cables can usually be routed along tracks or field boundaries to minimise disruption.

Roads
For access to the turbines, we require stone roads that are 5 m wide. Like the cables, we can normally route the roads to follow existing tracks or field boundaries. Once built, the roads must remain in place for access to carry out maintenance or repairs and are available for farm use.

Once Operating
When the turbines are in operation, normal requirements for access are limited. Unless there is a (rare) major fault, maintenance will be undertaken from a small van every three months. The turbines are monitored remotely via a telephone line so there is no need for more frequent visits. The control systems in the turbines are fail safe, so if a fault does occur the turbines stop automatically and communicate with the operating company via the telephone line.

Turbine Details
Modern wind turbines typically have a hub height of 67 m and a blade diameter of 80 m. When the blade passes its highest point, the tip will be at 107 m. At the lowest point, the tips are typically 27 m above ground level. For safety and turbine performance, it is necessary to have a separation between turbines equivalent to approximately 3 - 4 blade diameters, around 240 - 320 m.

A small building in the order of 6 x 8 metres is required to house a marshalling point for the cables from the individual turbines. This is called a switch gear house. From the switch gear house, an overhead line will be strung to a local substation. Despite the number of turbines, only one switchgear house is required per windcluster.