Wind Energy Flashcards
(25 cards)
Wind energy
- Renewable energy but depends on wind and wind speed.
- clean energy with no emissions.-
sustainable energy - less overall maintenance
- saving money for long term
Wind energy conversion
Wind power to turbine -mechanical power from turbine to gear box to generator - electric power from generator Ito power interface to grid.
History development of wind energy systems
I - catch wind for boats. 2-wind mills for grain grinding
Advantages of wind energy
1- renewable energy.
2 - reduce fossil fuel consumption.
3 - reduce thecost.
4 - creating jobs
5- efficient use of land space
Disadvantages of wind energy
1 - noise disturbance.
2- threat to wild life.
3- wind variability
4- suited to regions
What causes wind to blow?
When a difference in ATM pressure exists, air moves from higher to lower pressure area resulting in winds with variable speeds
Types of wind turbines
1- horizontal axis wind turbines hawt
2- vertical axis wind turbines VAWT
Characteristics of hawt
1 - horizontal axis of rotation.
2- generator placed on the tower.
3-two types: upwind - downwind.
Types of hawt
1- upwind turbines:blades are in front of wind - no shadowing effect - fewer power fluctuations - most dominant design.
2- downwind turbines: blades are behind the wind-shadowing effect- high power fluctuations - may be built without a yaw mechanism - used with small wind turbines.
Adv of hawt
Stable -tall towers so strong wind captured-high efficiency- self starting
Disadv of hawt
Maintenance is difficult _ difficult installation _ tall towers cause environmental problems
Vertical axis wind turbines VANT
1- vertical axis of rotation 2-generator is placed on the ground 3- it can capture the wind from all directions.
Adv of VANT
Omnidirectional (capture wind from all directions) _ easy maintenance - light weight towers.
Disadv of VANT
Blades are close to ground where wind speeds are low - poor self starting capabilities - overall poor performanceand not commercially used.
Rotor solidity
Ratio of blade area to the swept area ofwind turbine, solidity inc - weight inc - speed Dec - torque inc
Sizes and apps of wind turbines
1- small turbines: power <10 kW - installed in rural residential on grid and off grid _requires 4 m/s Aug wind speed - apps: homes-farm remote apps
2- intermediate turbine:power rating 10 - 500 kW - can be used in hybrid systems _. distributed power - apps in remote communities
3-large turbines: power rating 500 kW and more -installed in wind form arrays - requires 6 m/s wind speed - apps: central station wind farms - community power
Wind Power depends on:
Amount of air (volume) - speed of air (velocity) - mass of air (density)
Max rotor efficiency
Up wind speed before entering the turbine > wind speed at the plane of rotor blades> downwind speed after passing the turbine.
Effect of altitude on wind speed
Winds move slowly at ground level because of friction - friction diminishes with height so wind speed increases
Wind farm
Group of wind turbines in the samelocation used for production of electric power
Factors affecting wind farm siting
Wind speed-land use -aesthetic impact - sound impact -environmental impact -construction impact- infrastructure - political issues in PS
Wind speed
The faster wind speed the more electricity the turbine will generate - wind maps historical data
Land use
Wind turbines require large open space to avoid turbulence - developers must consider the size and placement of construction areas and electric equipment foundation
Aesthetic impact
People may see wind farms have negative impact on view - developers should avoid using wut for advertising - developers should avoid shadow flicker effect.
