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Lecture 15

NATS 1840 Lecture Notes - Lecture 15: Capacity Factor, Solar Irradiance

Natural Science
Course Code
NATS 1840
Carl Wolfe

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Friday, March 17, 2017
NATS 1840 Lecture Notes
Gaining a lot of traction.
Involves a wind turbines/wind mills
Harnessing kinetic energy of moving air.
This is fairly harmless in terms of environmental impacts.
Efficiency of capturing air is limited to about 59% (Betz limit). This is the max
Why can’t we capture all the energy of moving air? That would mean that air pressure
built up behind the turbine.
Commercial turbines typically reach about 45%.
Power output grows as cube of wind speed.
Turbines have a max speed at which they can turn before they fail structurally
because winds are too strong.
You have the surgery the wind speeds over a period of time to see how strong winds
are typically before building a turbine there.
Wind speeds are often well below rated speed —> limits capacity factor to 20-35%.
very high wind speeds are easy to find at the top of hills, near shore lines, or near
lakes. The terrains increases its speed.
Most opposite to turbines and wind farms have been largely social or political,
worrying about noice and property value, rarely environmental.
Wind is estimated to create 72 terawatts per year worldwide.
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