represented by the following two-parameter Weibull distribution (Weibull 1951;
Sakai and Tanaka 1984):
f V
ð Þ ¼
a
b
V
b
aÀ1
exp À
V
b
a
ð12:1Þ
F V
ð Þ ¼ 1 À exp À
V
b
a
ð12:2Þ
where Eq. (12.1) is the probability density function and Eq. (12.2) is the cumulative
distribution function. Parameter values can be obtained using the least squares
method (Sakai and Tanaka 1980, Ninomiya and Yoshioka 2020a, b). The mean
wind velocity, V m , is given by:
V m ¼ bΓ 1 þ
1
a
ð12:3Þ
and the power density of wind, PD, is given as follows:
PD ¼
1
2
ρb
3
Γ 1 þ
3
a
ð12:4Þ
where ρ is the density of air, given as ρ ¼ 1.225 kg/m
3 , and Γ(Á) is the gamma
function.
Fig. 12.4 Distribution characteristics of wind velocity during 2010. (Source: Kawai et al. 2010)
12 Building a Global Low-Carbon Society Based on Hybrid Use of Natural Clean Energy 221