wind – a renewable energy resource. wind energy transformations in wind turbines
TRANSCRIPT
Wind – a renewable energy resource
Wind
Energy transformations in wind turbines
Wind
• Moving air pushes against the blades of the turbine, making them spin.
• Some of the kinetic energy of the moving air is transformed into the mechanical energy of the spinning blades. (The wind still has some kinetic energy as it flows away from the turbine.)
• The shafts and the gears inside the gear box transfer energy from the turbine to the generator. (The gears make the drive shaft to the generator spin faster than the shaft connected to the blade hub.)
• The generator transforms mechanical energy into electrical energy.
• Some of the original kinetic energy supplied by the wind is ‘wasted’ as it is transformed into heat energy and sound energy within the turbine.
Image sourced fromhttp://www.alliantenergykids.com/wcm/groups/wcm_internet/@int/@aekids/documents/image/022691.jpg
How do wind turbines work?
Wind
Factors affecting the amount of electrical power produced by wind turbines include:
• The speed of the wind•The number of blades•The length of the blades•The shape of the blades•The pitch (angle) of the blades to the wind•The use of gears•The type of generator used
What affects the amount of electrical power produced?
Wind
Advantages of wind turbines include:•Wind is a renewable energy resource. It will never run out.
•Wind turbines do not produce greenhouse gases or other pollution when operating.
•Wind energy is free.
•Across the world there are regions where there are strong winds that can be used to generate electricity.
•Wind energy is available day and night.
•Wind turbines can be used in remote areas where there is no access to the electricity grid.
•Wind turbines are relatively efficient.
•Wind turbines can be installed on land where cattle or sheep graze.
Advantages of wind turbines
Wind
Disadvantages of wind turbines include:• The electrical power delivered varies because
wind speed and direction vary. Sometimes the wind speed is too low to even start rotation.
• Very strong winds can damage turbines.• It can be costly to connect a wind farm to the
electricity grid due to the distances involved.• Some people think they spoil the landscape.• Some people believe the sound they produce is
annoying or even harmful. However, tests by sound engineers have determined that the loudness of sound heard in any location depends on wind direction and speed, and that no infrasound (very low frequency sound) is produced
• There may be some impact on local bird populations.
Disadvantages of wind turbines
Wind
• Factors such as the topography of the surface of the Earth from where most of the wind comes, and of the site, have a big impact on the amount of electrical power that can be generated at a site.
• A good site might have a 35 % capacity factor – this means that the turbines will produce 35% of their capacity on average over a year.
• In many countries, most wind turbines are constructed off-shore , usually because people do not want them across the land. This is much more expensive, and presents problems such as corrosion by seawater.
Other Technical Issues
Wind
Communities can object to the installation of a proposed wind farms due to concerns about :•The potential damage to local sacred Aboriginal sites
•The effect on the appearance of the landscape and possible impact on any local tourist industry
•Noise
• The possible impact on the local environment, and on local populations of birds and other animals
Social Issues
Wind
What do you think of these objections?
Wind
In Australia
Snowtown Wind Farm
See STELR Case Study Notes
Wind
Some types of wind turbine may have a vertical axis
Darrieus turbine
Other vertical egg-beater turbines, with different blade shapes
Alternative Technologies
Wind
Example Early Stage Career Opportunities
Typ
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Sci
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Lev
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Development Approval OperationsConstruction
Project Development Stage
Wind Engineer
Development Engineer
Development Officer
Ecologists
Design Engineer
Heritage Monitors
Power Design
Engineer
Construction Manager
Community Engagement
Officer
Plant Optimisation
Engineer
Electrical Control
Engineer
Electrical Technician
Careers
See STELR Career Profiles
Wind
Career Profile
Name: Rick Morgans
Job: Wind Mapper
Employer: Cyclopic Energy
•Rick measures and simulates the wind flow for potential sites for small scale wind turbines in cities, using computer modeling
•Read Rick’s career profile on the STELR website.
Career Profiles
Name: Cindy Hull
Job: Avian Ecologist
Employer: Roaring 40s
•Finds ways to reduce the impact of wind farms on bird populations
•Read Cindy’s career profile on the STELR website.
Wind
Wind
• What energy transformations occur when a wind turbine operates?
• Why is wind energy considered to be a renewable energy resource?
• What factors affect the amount of energy ‘captured’ by a wind turbine?
• How efficient are wind turbines?
• What are three disadvantages of using wind turbines to produce electrical energy?
• List two issues that scientists and engineers need to consider when developing a wind farm.
Revision Questions