Wind Energy

Question 1

What is the (1) minimum speed required to rotate most wind turbines, and (2) the maximum cut-out speed?

Answer 1

8 kph, 90 kph

Question 2

What wind speed range does a typical turbine generate maximum power?

Answer 2

36 kph to 54 kph

Question 3

What are the two common complaints from local people when wind turbines are installed?

Answer 3

Visual impact, noise

Question 4

Wind is an intermittent power source. Why is this an issue?

Answer 4

The grid has little storage capacity, so if the wind drops there could be a blackout.

Question 5

How does the law of large numbers apply to wind power generation?

Answer 5

The aggregate power generation of all the power stations will be less volatile than the power generation of a single station.

Question 6

Why is a pitch system an important component of a wind turbine?

Answer 6

Controls rotor speed, preventing them from turning at too high or low speeds to generate electricity.

Question 7

What does a gear box do in a wind turbine?

Answer 7

Connects the low speed shaft to the high speed shaft

Question 8

(1) What rpm does a low speed shaft run at? (2) What rpm does a high speed shaft run at?

Answer 8

(1) 30-60 rpm, (2) 1000-1800 rpm

Question 9

What does the generator do in a wind turbine?

Answer 9

Produces 60-cycle AC electricity

Question 10

What is the role of a yaw drive in an upwind turbine?

Answer 10

Orients upwind turbines towards the direction of the wind.

Question 11

Offshore wind speeds tend to be slightly faster than on land. (1) Explain why this is, and (2) Why is this such a big issue for power generation?

Answer 11

(1) Less low-altitude wind disruption. (2) Small increases in wind speed corresponds to large increases in power generation.

Question 12

List 4 cons of wind power generation.

Answer 12

Any 4 of: noise, visual impact, electromagnetic interference, lower property values, high installation costs, can kill birds

Question 13

How does the NIMBY phenomenon apply to wind turbines?

Answer 13

People support wind power generation but don’t like local wind turbines.

Question 14

In a wind turbine, why does the pitch system prevent the rotors from spinning at low wind speeds?

Answer 14

Insufficient power generation at low speeds,, so the rotors spinning causes pointless wear to the wind turbine

Question 15

In what environment does a wind turbine need to be placed for maximum power generation?

Answer 15

Usually in rural areas with a naturally high amount of wind, with no obstacles nearby (e.g. houses, hills, forests)

Question 16

Why do wind farms tend to be placed in rural areas? (Give two reasons)

Answer 16

Fewer obstacles to wind flow, less residents to complain about visual/noise impact

Question 17

Why are taller wind turbines attractive?

Answer 17

They are more likely to access higher speed winds

Question 18

What is the basic physical principal behind an electric generator?

Answer 18

Copper coils move relative to stationary magnets and induce a potential difference

Question 19

The O-wind turbine design is particularly innovative because …

Answer 19

It ensures the shaft spins at a constant rate regardless of wind direction.

Question 20

Managing the use, development and protection of natural and physical resources in a way, or at a rate which enables people and communities to provide for their social, economic, and cultural well-being and for their health and safety is handled in New Zealand by the ______ ________ ___.

Answer 20

Resource Management Act

Question 21

How often does the price of electricity change in New Zealand’s wholesale market?

Answer 21

Every 30 mins