Siting - Wind Energy: Renewable Energy and the Environment - page 189

FIGURE 9.11 West side of wind farm in the Plains, near White Deer, Texas. White lines are for roads,
2.5 km 2 , 1 square mile. (Photo from Cielo Wind Power. With permission.)
of wind farms in other terrain are shown in Figures 9.12 to 9.14 . A photo of an offshore wind farm
is shown for comparison ( Figure 9.15 ) .
The amount of land taken out of production depends primarily on length and width of roads con-
structed on the wind farm. Values vary from 0.5 to 2 ha per wind turbine. If there are county roads,
the wind farm developer will use less land; however, the developer will probably have to improve
the county roads for the heavier traffic. If it is on a mountain ridge, the roads may be very expensive.
The road from the bottom to the top for access to the Texas Wind Project at the Delaware Mountains
cost $1 million in 1993.
There are the civil engineering aspects for wind farm site, such as location of assembly area,
electrical substation, and roads (width and grade in complex terrain). Note that roads have to have
wide turns for trucks hauling the long blades. In many cases a batch cement plant is on site, espe-
cially for complex terrain of ridges and mesas.
A general rule of thumb is that around 5-9 MW/km 2 can be installed on land that is suitable for
wind farms. However, on ridgelines, at 2D to 3D spacing, the value would be around 8-12 MW/
linear km. This assumes that the ridge is more or less perpendicular to the predominant wind flow.
As wind turbines become larger, the megawatts per square or linear kilometer will increase due to
FIGURE 9.12 Wind farm in rolling terrain, Lake Benton, Minnesota. (Photo by Wade Weichmann. With
permission.)