Wind Energy

Question 1

Wind energy

Answer 1

• Renewable energy but depends on wind and wind speed.
• clean energy with no emissions.-
  sustainable energy
• less overall maintenance
• saving money for long term

Question 2

Wind energy conversion

Answer 2

Wind power to turbine -mechanical power from turbine to gear box to generator - electric power from generator Ito power interface to grid.

Question 3

History development of wind energy systems

Answer 3

I - catch wind for boats. 2-wind mills for grain grinding

Question 4

Advantages of wind energy

Answer 4

1- renewable energy.
2 - reduce fossil fuel consumption.
3 - reduce thecost.
4 - creating jobs
5- efficient use of land space

Question 5

Disadvantages of wind energy

Answer 5

1 - noise disturbance.
2- threat to wild life.
3- wind variability
4- suited to regions

Question 6

What causes wind to blow?

Answer 6

When a difference in ATM pressure exists, air moves from higher to lower pressure area resulting in winds with variable speeds

Question 7

Types of wind turbines

Answer 7

1- horizontal axis wind turbines hawt
2- vertical axis wind turbines VAWT

Question 8

Characteristics of hawt

Answer 8

1 - horizontal axis of rotation.
2- generator placed on the tower.
3-two types: upwind - downwind.

Question 9

Types of hawt

Answer 9

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.

Question 10

Adv of hawt

Answer 10

Stable -tall towers so strong wind captured-high efficiency- self starting

Question 11

Disadv of hawt

Answer 11

Maintenance is difficult _ difficult installation _ tall towers cause environmental problems

Question 12

Vertical axis wind turbines VANT

Answer 12

1- vertical axis of rotation 2-generator is placed on the ground 3- it can capture the wind from all directions.

Question 13

Adv of VANT

Answer 13

Omnidirectional (capture wind from all directions) _ easy maintenance - light weight towers.

Question 14

Disadv of VANT

Answer 14

Blades are close to ground where wind speeds are low - poor self starting capabilities - overall poor performanceand not commercially used.

Question 15

Rotor solidity

Answer 15

Ratio of blade area to the swept area ofwind turbine, solidity inc - weight inc - speed Dec - torque inc

Question 16

Sizes and apps of wind turbines

Answer 16

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

Question 17

Wind Power depends on:

Answer 17

Amount of air (volume) - speed of air (velocity) - mass of air (density)

Question 18

Max rotor efficiency

Answer 18

Up wind speed before entering the turbine > wind speed at the plane of rotor blades> downwind speed after passing the turbine.

Question 19

Effect of altitude on wind speed

Answer 19

Winds move slowly at ground level because of friction - friction diminishes with height so wind speed increases

Question 20

Wind farm

Answer 20

Group of wind turbines in the samelocation used for production of electric power

Question 21

Factors affecting wind farm siting

Answer 21

Wind speed-land use -aesthetic impact - sound impact -environmental impact -construction impact- infrastructure - political issues in PS

Question 22

Wind speed

Answer 22

The faster wind speed the more electricity the turbine will generate - wind maps historical data

Question 23

Land use

Answer 23

Wind turbines require large open space to avoid turbulence - developers must consider the size and placement of construction areas and electric equipment foundation

Question 24

Aesthetic impact

Answer 24

People may see wind farms have negative impact on view - developers should avoid using wut for advertising - developers should avoid shadow flicker effect.

Question 25

Wind resource assessment

Answer 25

Wind resource maps - on site measurements -calculations - software and simulation.