Table 1-1 Classes of wind power density at 10 m and 50 m(a).
Wind Power
Class*
10 m (33 ft) 50 m (164 ft)
Wind Power Density (W/m2) Speed(b) m/s (mph) Wind Power Density (W/m2) Speed(b) m/s (mph)
  1 0 0 0 0
100 4.4 (9.8) 200 5.6 (12.5)
  2
150 5.1 (11.5) 300 6.4 (14.3)
  3
200 5.6 (12.5) 400 7.0 (15.7)
  4
250 6.0 (13.4) 500 7.5 (16.8)
  5
300 6.4 (14.3) 600 8.0 (17.9)
  6
400 7.0 (15.7) 800 8.8 (19.7)
  7
1000 9.4 (21.1) 2000 11.9 (26.6)


(a) Vertical extrapolation of wind speed based on the 1/7 power law.

(b) Mean wind speed is based on Rayleigh speed distribution of equivalent mean wind power density. Wind speed is for standard sea-level conditions. To maintain the same power density, speed increases 3%/1000 m (5%/5000 ft) elevation.


*WEB NOTE: Each wind power class should span two power densities. For example, Wind Power Class = 3 represents the Wind Power Density range between 150 W/m2 and 200 W/m2. The offset cells in the first column attempt to illustrate this concept.


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