Environmental Engineering Reference
In-Depth Information
automatically adjusts the pitch of the blades in response to wind speed vari-
ance.
6
In a location that is characterized by inconsistent winds, adjustable
rotor blades will, provided other conditions remain the same, proitably
improve power output and generation consistency.
7
As another example,
the development of better tower technology makes it possible for higher
towers that enable turbines to capture high quality wind which is less inlu-
enced by ground friction.
8
Second, technical economies of scale have emerged as bigger units pro-
duce more energy for less cost. he rated power generation capacities of wind
turbines have increased signiicantly since the early 1980s. State of the art
20 kW wind turbines of the 1980s now seem like school science projects in
comparison to the 6000 kW turbines that are being erected today. All of the
main components of wind systems—the nacelle components (blade, gears,
and generator), the tower, the foundation and the balance of plant compo-
nents (including transformer and transmission cables)—have declining cost
proiles in relation to increased scale. For example, a turbine with twice the
power capacity of another does not require twice the tower height, nor does
it require twice the foundation materials or twice the resource inputs for bal-
ance of plant components. However, there are diminishing returns in regard
to technical economies of scale. One wind expert contends that in the near
future, technical economies of scale may be obviated by ampliied increases
in the cost of larger wind turbines. Simply put, building larger turbines
higher of the ground eventually requires excessively expensive structural
reinforcement. Furthermore, the weight of the rotor blade inevitably limits
the extent to which the size of the swept area can be expanded;
9
however,
engineers disagree over how much progress is still achievable. For the time
being, technical economies of scale continue to be realized. Advances in tur-
bine technology, lighter component materials, and improvements in wind
capture engineering continue to drive down generation costs.
hird, there are production economies of scale that have contributed to
the overall reduction of wind power generation costs in the same manner
that Henry Ford's production line contributed to lower automobile assem-
bly costs. Wind experts Ackerman and Soder estimated that in the 1990s,
wind power cost declined by 20% every time the aggregate amount of global
installed wind power capacity doubled.
10
Although experience from other
industries suggests that further market growth will likely provide diminish-
ing returns regarding production economies of scale, the consensus appears
to be that over the next few decades, as the wind power market expands,
production economies of scale will continue to contribute to lower gen-
eration costs and this will fuel further market expansion because market
growth and cost enjoy a symbiotic relationship. Danish developer DONG
