Wind Power Flashcards
(26 cards)
What are the advantages of wind power?
Free
Renewable/sustainable - cannot be used up
Abundant
Clean - no CO2
no transportation or storage required
available across the globe
What are the disadvantages of wind power?
Very inefficient
Unpredictable - energy storage may be required
Visual/noise impact
radio interference
Costly
Environmental impact - marine/birds
Needs other sources such as nuclear when wind is low
What causes Wind?
Uneven solar heating by the Sun
Pressure variations caused
Which was does the wind curve in each hemisphere and why?
Northern - Right
Southern - Left
Why - Coriolis Effect
What is the relationship between solidity and speed?
Inverse relationship
What are the attributes of modern wind turbines?
Low solidity but high speed, maximise power
What are the most expensive costs in a wind turbine?
Wind turbine
Foundation
Electrical System
What are the benefits of offshore?
Steadier wind
Larger turbines
What are the downsides of offshore?
Higher upfront cost
Maintenance costs
harsher environment
What is the cut in speed?
Lowest operational speed
What is the cut out speed?
Highest operational speed
What is the rated wind speed?
The speed when the wind turbine reaches rated power
What is rated power?
Maximum power produced
What is the equation for power law?
Vz/Vref = (Z/Zref)^alpha
What are the strategies for controlling a wind turbine against overspeed?
Stall regulation
Pitch regulation
Yaw control
What is V50
The wind speed that is exceeded for half of a year
What is the maximum Cp (power coefficient) value
59%
What is the equation for Cp with alpha in it?
Cp = 4 alpha (1 - alpha)^2
What is another way of saying capacity factor?
Productivity
What is the equation relating radius to other factpors?
x_A / x _B = (R_A / R_B)^y
What are the values of y for power, torque, rotation and weight?
Power, y = 2
Torque & Weight, y = 3
Rotation, y = -1
What are the benefits of a direct drivetrain?
Lower losses
Less maintenance
Cheaper
What are the benefits of an indirect drivetrain?
More efficient electrical generation
higher power output
What is the depth range for a jacket structure?
35 - 60 m
