04-08-2012, 12:46 PM
Low Speed Wind Turbines
LowSpeedTurbines.pdf (Size: 396.05 KB / Downloads: 952)
Why low wind speed turbines?
• Easily accessible prime class 6 sites are
disappearing.
• Many class 6 sites are located in remote
areas without easy access to transmission
lines.
• Without advances in technology to make
low wind speed sites more cost effective,
wind energy may plateau in the near
future.
Available Wind Power
• The amount of energy that a wind turbine can
produce is dependant on the wind regime where
it is located and the efficiency with which it
captures the wind.
• The wind regime is defined by three
characteristics:
– the average wind velocity,
– the Weibull distribution of the wind velocity,
– and the shear (and turbulence) of the wind at the
turbine location.
Economic Considerations
• Cost of Energy (COE) is largely based on
capital cost rather than efficiency since the
fuel is free.
• The cost of a wind turbine can be modeled
by the weight of the components.
• The loads experienced by the turbine drive
the section modulii of components, which
drive the weight, which drive the cost.
Specific Rating Options
• Most turbine manufactures offer multiple
specific ratings for a turbine e.g.:
– GE 1.5 and 2.X
– NEG Micon NM72, NM82
– Nordex N60/62, S70/77
– Vestas V80, V90
• These turbines employ either multiple rotor
sizes and/or multiple generator sizes for
the same turbines.
Advanced Materials and Rotor Designs
• Rotor costs represent ~15% of wind turbine
initial capital costs (ICC)
• Current rotor blades are already pushing the
envelope of manufacturing methods and
materials.
• Rotor blade will use carbon fibers and fabrics to
avoid cubic weight increase with diameter
increase.
• Better manufacturing processes will improve
mean material properties (e.g. fiber alignment,
void reduction) without compromising stiffness.