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Wind Power :wind_blowing_face: - Coggle Diagram
Wind Power
:wind_blowing_face:
Harnessing
:hammer_and_wrench:
Early uses of wind harnessed the kinetic energy of the winds to drive machinery such as grain mills/water pumps
Modern turbines generate electricty
Most aerogenerators have blades or vanes that rotate around an axis
Either vertical or horizontal plane
Vertical Axis Wind Turbine (VAWT)
Horizontal Axis Wind Turbine (HAWT)
Aerogenerators absorb the kinetic energy of moving air
Air behind the turbine moves more slowly
Individual turbines must be spaced so that they are not in the wind shadow
HAWT
:straight_ruler:
Advantages :check:
Tech is more advanced/established than VAWTs :check:
Higher efficiency than VAWTs :check:
Disadvantages :green_cross:
Stress cracking can occur at the base of the blades :green_cross:
Due to Cyclical gravitational forces :green_cross:
:green_cross: Taller towers are needed to keep the blades above the ground
:green_cross: The weight of the generator requires a stronger tower than VAWTs
VAWTs generators can be at ground level
VAWTS
:v:
Advantages :check:
Turbines are driven by wind in any direction :check:
Can be used where winds are turbulent :check:
Cities
Do not need to be turned to face into the wind :check:
No need for a motor :check:
Quieter than HAWTS :check:
Operate at lower wind velocities :check:
Disadvantages :green_cross:
No very large VAWTs have been built :green_cross:
Lower efficiency as blades are not absorbing wind energy throughout their rotation :green_cross:
Differences in atmospheric pressure are produced by regional differences in heating by solar energy
Wind blows the equalise these pressure differences
Locational Constraints
:world_map:
Wind velocity
:speedboat:
Reliability/strength is affected by latitude
Windiest areas in temperate and polar regions
Topography affects wind velocity
Friction and turbulence - Slow wind down
Areas with a higher wind velocity
Coastal Areas
Upland areas
Flat Areas
The Sea
Harnessing power in the windiest aras is important
High wind velocity produce more power
A doubling in velocity results in an eight-fold increase in kinetic energy
Isolation
:silhouette:
small scale wind power can provide electricity for isolated uses
Small rural communities
Large scale wind farms may be located near the existing electricty grid
Avoids cost of laying new cables to join
Land use conflicts
:angry:
Conflicts can arise from a range of conflicting needs/preferences
Ecological impact
:bird:
Turbines may be located away from:
Bird migration routes
Bat populations
Sensitive habitats -bogs
Foundations/access tracks affect hydrology
Land requirements
:male-farmer::skin-tone-4:
Turbines in a windfarm need large areas of land
So aerogenerators can be dispersed
To minimise wind shadow aerogenerators are spaced with an interval of 3 to 5 times the diameter of the blades
The land between the aerogenerators can be used for other things
Agriculture
Amount of land actually lost is smaller than the overall area of the windfarm
Telecommunication interference
:radio:
Aerogenerators can interfere with radio/radar systems
Public Opposition
:silhouettes:
Some people object to wind farms
Located away from scenic/urban areas
Environmental Impacts
:evergreen_tree:
Manufacture and Installation
:construction_worker::skin-tone-4:
material manufacture and installation have environmental impacts during the production of materials, transport, installation
Noise
:loudspeaker:
Rotating aerogenerators are less noisy than many everyday anthropogenic sources of noise
People who live close, the rhythmic sound may be irritating
More aerodynamic blade designs and direct drive aerogenerators with no gearbox are quieter
Habitat damage
:explode:
The habitat area that is destroyed by the foundations is small
Habitat required for access paths and transformers is larger
Bird strikes
:eagle:
Rotating blades may kill bords
Likely when there located along migration paths, places where birds soar and where they congregate - wetlands
Careful location reduces deatsh
VAWTs are less likely to cause deaths than HAWTs as they're seen more easily
Bat deaths
:bat:
Changes in air pressure kills bats
Bats usually fly when wind speeds are low
This is when wind turbines produce little energy
In areas where there is a high risk of bat death
Turbines may be stopped during low wind velocity periods
New technology
:desktop_computer:
Blade-tip fins
:whale2:
Reduce turbulence and wind resistance
Increasing efficiency
Nacelle brushes
:lower_left_paintbrush:
Reduce the amount of air escaping between the base of the blades and central nacelle (hub)
This increases the amount of kinetic energy absorbed by the blades
Direct drive turbines
:racing_car:
Most turbines have a gear box to ensure the generator turns at 3000rpm
Producing the 50 cycle per second alternating current (AC) electricity that has to be fed to the national grid
This gearbox is expensive and a common cause for mechanical breakdown
Friction in the gear box reduces efficiency and increases the wind velocity that the blades start to rotate
Direct drive have no gearbox:!:
More reliable, cheaper, quieter and start at lower wind velocities
Generator produces DC electricity which is converted to AC that can be fed to the grid
Using an invertor
Helical VAWT Blades
:ear:
VAWTs with straight blades do not rotate smoothly
Some positions absorb more energy than others
Reducing efficiency of the electricity fed into the grid
Leads to stress and strain problems
Wind assisted ships
:boat:
Intermittency of winds and the difficulty sailing against the wind
Means commercial shipping is unlikely to solely use wind
Wind assisted ships that use wind power to reduce energy provided by the engine
Designed and built using aerofoil wings, mechanically controlled sails or a kite sail
Maltese Falcon
Demonstrates a sail rig that was designed for use on wind-assisted cargo ships
Can be operated by a single crew member
Many other designs have been proposed/demonstrated but have not yet become established