WIND ENERGY SYSTEMS - Cd3wd

Chapter 2—Wind Characteristics 2–10
TABLE 2.1 Annual Percentage Frequency of Wind by Speed Groups and the Mean Speed a
Mean Peak
0–3 4–7 8–12 13–18 19–24 25–31 32–38 Speed Speed b
Station mi/h mi/h mi/h mi/h mi/h mi/h mi/h (mi/h) (m/s)
Albuquerque 17 36 26 13 5 2 8.6 40.2
Amarillo 5 15 32 32 12 4 1 12.9 37.5
Boise 15 30 32 18 4 1 8.9 27.3
Boston 3 12 33 35 12 4 1 13.3 38.9
Buffalo 5 17 34 27 13 3 1 12.4 40.7
Casper 8 16 27 27 13 7 2 13.3 NA
Chicago(O’Hare) 8 22 33 27 8 2 11.2 38.9
Cleveland 7 18 35 29 9 2 11.6 34.9
Cold Bay 4 9 18 27 21 14 5 17.4 NA
Denver 11 27 34 22 5 2 10.0 29.0
Des Moines 3 17 38 29 10 3 1 12.1 34.0
Fargo 4 13 28 31 15 7 2 14.4 51.4
Ft. Worth 4 14 34 34 10 3 12.5 30.4
Great Falls 7 19 24 24 15 9 3 13.9 36.6
Honolulu 9 17 27 32 12 2 12.1 30.0
Kansas City 9 29 35 23 5 1 9.8 32.2
Los Angeles 28 33 27 11 1 6.8 21.9
Miami 14 20 34 20 2 8.8 59.0
Minneapolis 8 21 34 28 9 2 11.2 41.1
Oklahoma City 2 11 34 34 13 6 1 14.0 38.9
Topeka 11 19 30 27 10 2 11.2 36.2
Wake Island 1 6 27 48 17 2 14.6 NA
Wichita 4 12 30 31 16 5 1 13.7 44.7
a Source: Climatography of the United States, Series 82: Decennial Census of the United State Climate,
“Summary of Hourly Observations, 1951–1960” (Table B).
b NA, not available
an hour but the magnetic tape only has data for every third hour, so there are eight wind
speeds and eight wind directions per day available on the magnetic tape.
The available data can be summarized in other forms besides that of Table 2.1. One form
is the speed-duration curve as shown in Fig. 6. The horizontal axis is in hours per year, with
a maximum value of 8760 for a year with 365 days. The vertical axis gives the wind speed
that is exceeded for the number of hours per year on the horizontal axis. For Dodge City,
Kansas, for example, a wind speed of 4 m/s is exceeded 6500 hours per year while 10 m/s is
exceeded 700 hours per year. For Kansas City, 4 m/s is exceeded 4460 hours and 10 m/s is
exceeded only 35 hours a year. Dodge City is seen to be a better location for a wind turbine
Wind Energy Systems by Dr. Gary L. Johnson November 20, 2001