Wind Power

Wind Patterns Global winds Sea and land

breezes Valley winds

Global Wind

Sea, land, and valley winds

Wind Rose Direction Speed Frequency

Equations

Wind power increases as the square of diameter, but cube of wind speed

(W)power is P (m/s) speed windis V

(m)diameter rotor is d

3kg/m 1density air is

disk blade of area anddensity with increases m (kg) blades through going streamair of mass is m

328

221

VdP

VmE

Scaling (Example) A wind turbine (d=3m) generates 10

kW of power at wind speed of 4 m/s.How much power will it produce If the turbine diameter were increased to 6 m? If wind speed suddenly increased to 12 m/s? With the same wind conditions, would turbine

produce more power in winter or summer?

Wind Turbine Principle of operation

Design Considerations Rotor Size Number of blades Gearbox Generator Controls

Advantages and Disadvantages

Advantages• Clean• Renewable

Disadvantages• Intermittent• Wind speed not too slow, not too fast• Noise• Aesthetic• Dangers to birds

Siting Wide areas with open

views in all direction Valleys and ridges Close to power grid Away from towns and

population centers

Future