WMOD00469

• Title: Environmental Impact of Large Windpower Farms
• Weather Modification - Doc Type: Report

i.

FY74
o

FY75

FY76

Transi ti onal
~rter _

FY77

FY78

$422,000 $200,000.

$300,000

$199,000 $200,000
(approximate)

Two I-year contracts totaling $200,000 wer-e let in FY76. One to the
Radiation Laboratory of the University of Michigan, \"/as to find out
hO\'I wi nd-machi ne blades refl ect radi 0 waves and the effect of theSE!
reflections on radio and television reception, derive criteria for
testing how receiver performance depends on the location of transmitter.
receiver, and wind machine, and try them out on NASAls Plum Brook,
Ohio installation. The second contract, let to the Battelle
Memorial Institute as a second-year follow-on, pursued the microclimatic
effects of the Plum Brook machine on sun exposure, rainfall, and
windspeed near the installation, and the effect of its rotating
blades on migratory birds during the spring and autumn migrations.

An estimate of what major environmental issues might arise from
further development of windpowered generators was published by the
Energy Research and Development Administration (1977). The machine-
centered impacts that it identified included the incidents of
manufacture, pl acement, and eventual removal; possi bl e mi crocl imatjj c
effects in the immediate vicinity of an individual machine; the
characteristics of an individual machine as a reflector of radio
waves and a generator of interferenCE! patterns in them; hazard to
airborne objects such as birds and airplanes; effects on immediately
adjacent vegetation and animals as a consequence of microclimatic
alterations; responses of people to the aesthetic aspects of various
forms of wind machine; and the hazards arising from possible mechanical
failure of a machine. It also considered briefly the environmental
implications of large numbers of windpowered generators in the
aggregate on land use and reclamation and socioeconomic effects on
rural populations. It recommended further research on television
interference, microclimatic effects, and structural failures.

3. Impacts of Large Windfarms

a. Microclimatic. - A large windfarm will increase the roughness
of the earth's surface in its immediate area, thus affecting both
the distribution of wind in the vertical and the details of wind
swirl patterns at the ground. These changes will in turn affect
the local details in the patterns of temperature, precipitation,
snow drifting, and evaporation.

The effects of increased terrain roughness have been studied in
connection with the microclimatic effect of cities, which roughen
the earth I s surface to an even grl:!ater extent and over even
larger areas than would be the case with windfarms.

3