
145Wind Energy
© 2008 Taylor & Francis Group, LLC
Sophisticated control systems required to point turbine blades into wind, prevent
overspeed conditions, etc.
Readers interested in more information on a variety of WT concepts are directed to [19,20].
3.5 Introduction to Wind Turbine Performance
A key performance measure in WT design is the coefcient of performance, C
p
, which is
a ratio of the aerodynamic power extracted by the WT, P
aero
, divided by the total power in
the wind, P
wind
, and is calculated as
C
P
AU
RU
p
aero
wind
aero aero
== =
12 12
3
π
(3.13)
The theoretical maximum turbine efciency was derived by Albert Betz in 1920 [21], as
wel