WIND ENERGY SYSTEMS - Cd3wd

Chapter 2—Wind Characteristics 2–13
Figure 8: Annual mean wind power density W/m 2 estimated at 50 m above exposed areas.
have much higher wind power densities. Mt. Washington in New Hampshire has an average
wind speed of over 15 m/s, twice that of the best site in Table 2.1. The annual average wind
power density there would be over 3000 W/m 2 . Mt. Washington also has the distinction of
having experienced the highest wind speed recorded at a regular weather data station, 105
m/s (234 mi/h). Extreme winds plus severe icing conditions make this particular site a real
challenge for the wind turbine designer. Other less severe sites are being developed first for
these reasons.
Superior sites include mountain passes as well as mountain peaks. When a high or low
pressure air mass arrives at a mountain barrier, the air is forced to flow either over the mountain
tops or through the passes. A substantial portion flows through the passes, with resulting
high speed winds. The mountain passes are also usually more accessible than mountain peaks
for construction and maintenance of wind turbines. One should examine each potential site
carefully in order to assure that it has good wind characteristics before installing any wind
turbines. Several sites should be investigated if possible and both hills and valleys should be
considered.
Wind Energy Systems by Dr. Gary L. Johnson November 20, 2001