FAQ

  1. How does a wind turbine work?
  2. Are wind turbines noisy?
  3. Are the wind resources in Hong Kong sufficient enough to develop wind power projects?
  4. What is meant by the "capcity factor" of a wind turbine or a wind farm?
  5. What are major factors governing the power output of a wind turbine?
  6. Can large wind turbiness be installed in urban areas?
1. How does a wind turbine work?
Ans: A wind turbine converts the kinetic energy in the wind into mechanical energy to drive an electric generator. A wind turbine blade works like an aircraft wing, generating a lifting force when wind blows over it, making the turbine rotor turn.
   
2. Are wind turbines noisy?
Ans: A wind turbine rotates rather slowly and generates relatively little noises. Noise of a wind turbine mainly comes from two sources, i.e the mechanical moving parts and the interaction of the rotating blades with the air. With better design of mechanical parts and power electronic controls and lower rotational speed, noise emitted by modern wind turbines can be minimized.
   
3. Are the wind resources in Hong Kong sufficient enough to develop wind power projects?
Ans: Local wind resources are moderate and at certain areas the wind resources are adequate for the development of wind power projects. The Wind Resource Maps section of this website provide numerical information on the available wind resources at various locations throughout the territory.
   
4. What is meant by the "capcity factor" of a wind turbine or a wind farm?
Ans: The capacity factor is the ratio of the annual energy yield (in kWh) divided by the product of rated power and 8760 hours. The capacity factor times 8760 hours is equal to the number of equivalent full-load hours of a wind turbine or wind farm. Since wind energy is an intermittent resource, a 100 kW turbine will not generate electricty at full capacity for all 8760 hours in a year. If it generates 200,000 kWh of electricity throughout a year, the capacity factor is equal to 200,000 kWh / (100kW x 8760 hr) = 23%. 23% times 8760 hours equals 2000 full-load hours.
   
5. What are major factors governing the power output of a wind turbine?
Ans: As indicated in the formula for calculating the power in the wind, wind speed and swept area of a turbine are the major factors governing the power output of a turbine, as power in the wind is proportional to the cube of wind speed and is proportional to the swept area of the turbine. Another major factor is the design of the turbine blade and the control mechanisms, which affect the ability to capture the power in the wind and convert it into electrical energy.
   
6. Can large wind turbiness be installed in urban areas?
Ans: It is possible to install large wind turbine in the sparsely populated urban area, but not in the densely populated area. An example of an urban wind turbine is the 750kW one by the lake at Exhibition Place in Toronto.
   
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