WMOD00522

• Title: Projected Impacts of a Very Large Windpower Complex
• Date: 9/26/1978
• Weather Modification - Doc Type: Report

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centers --- comprise the legs of a tripod supporting the concept of the
windpower system with which this presentation deals.

2. Characteristics of Windfarms in the Projected Complex

The windpower that can be harvested from the atmosphere at a given
site by a given machine varies with the cube of the windspeed between the
cut-in speed of the machine and the windspeed at which it reaches its maximum
rated power output (typically 8 to 10 m/s). The power output from the
machine then remains constant or decreases as the wind increases up to the
cut-out speed, falling to zero when the machine cuts out. Best costo-effective-
ness involves a compromise between the advantages of extracting maxilnum
energy from strong winds and the disadvantages of having the machine working
at less than its full capacity much of the time. It is believed that optimi-
zation will result in a relationship between average wind energy density and
average cost of energy at the windfarm about as shown in Figure 1 ~ It
indicates that the windiest site permitted by prevailing constraints enjoys a
very large cost advantage.

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ANNUAL AVERAGE POWER (Wm-2)
MEASURED 10m ABOVE GROUND LEVEL

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F. 1. Variation of estimated windpower
~g. 3
with average windpower density, after Todd