Eric Rosenbloom, currently the president of National Wind Watch, has observed from cumulative output vs. time graphs (see the samples from Germany, Ireland, and Denmark) the following:
Whatever the capacity factor, or average output over a period of time, any turbine or aggregate of turbines generates at or above its average rate only 40% of the time.A recent illustration of this law is the output from the 240-MW Maple Ridge wind energy facility in Lewis County, N.Y., as compiled by Richard Bolton:
For this period from July through September 2006, the output represented 25% of capacity, or an average rate of 80 MW. As the graph shows, the facility produced at a rate of 90 MW or more only about 520 out of the total 1,883 hours of data collection, i.e., about 28% of the time. Adding the number of hours that it generated at 80-90 MW brings the time figure close to a third.
wind power, wind energy, wind farms, wind turbines
