The Jacobs Wind Energy Systems 31-20 Wind Turbine that Wright-Hennepin Electric put up has a year to date output of 5981kWh.
This works out to 18.4kWh per day this year or 766.66Wh per hour.
If you calculate the power using a cP of 25% and the Rockford, MN average wind speed of 5.3m/s this 31-20 Wind Turbine should get get 38.4kWh per day.
HWP = 0.5 x 1.23 x SA x WV^3 x cP
(HWP) Harvestable Wind Power (w/hr) = 0.5 x AD (air density kg/cu m) x SA (sweep area m^2) x WV^3 (wind velocity m/s) x cP (coefficient of performance Betz limit 59.26%, R^1 or Copper loss, linear power curve to cubic curve matching — 0.25 for most systems)
HWP = 0.5 x 1.23 x 3.14 x 15.5 x 15.5 x 0.09260304 (69.853) x 5.3 x 5.3 x 5.3 (148.877) x 0.25 = 1599Wh
1.599Wh x 24 = 38.4kWh per day.
So lets work out the cP of this unit.
So if HWP = 0.5 x 1.23 x SA x WV^3 x cP
then cP = HWP / 0.5 x 1.23 x SA x WV^3
cP = 766.66 / 0.5 x 1.23 x 69.853 x 148.877
is a cP of 0.119 which is not very good.