Page 302 - Handbook of Energy Engineering Calculations

of 1000 ft (300 m), the total available wind power is larger by a factor of 10
in comparison with that at 150 ft (50 m), Fig. 7.
Wind energy was welcomed by environmentalists when first introduced on
a large-scale basis in the late 70s and early 80s. Today all environmental
groups support wind energy—but with less enthusiasm than earlier. The

reason for the loss of enthusiasm? Windmills are killing birds that fly into
them.
Some of the birds killed by windmills are endangered species, so

environmentalists seek a solution to prevent the killing of hundreds of birds a
year that crash into the 17,000 l00-ft (30.5-m) windmills erected in California
where 80 percent of the world’s wind power is produced.
A number of states are considering construction of windmill “farms”
where thousands of power-generating windmills will be clustered together.

Environmentalists are concerned that such farms will raise the death toll
among birds. Wind turbine manufacturers estimate that from two to six birds
are killed per year per 100 wind turbines.