1. Offshore Wind Turbines
RENEWABLE ENERGY COURSE
The group:
Pengmei WU
Fan ZOU
Aitor COLINAS
Clément BERTRAND
Loïc DELATTRE
Supervisor: Prof Göran WALL
October 2006

2. Summary
1° CONDITIONS OF THE OFFSHORE WIND ENERGY
2° FUNCTIONING OF OFFSHORE WIND TURBINES
3° LOCATION
4° THE ECONOMICAL ANALYSIS OF OFFSHORE WIND FARMS
5° SOME COMPARISONS
CONCLUSION

3. CONDITIONS OF THE OFFSHORE WIND ENERGY

4. CONDITIONS OF THE OFFSHORE WIND ENERGY THE MOST INFLUENCIAL CONDITIONS
                                                                                                                        
Wind Turbine Glossary
Anemometer: Measures the wind speed and transmits wind speed data to the controller.
Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
Brake: A disc brake which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat.
Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.
Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-speed shaft: Drives the generator.
Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Nacelle: The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician to stand inside while working.
Pitch: Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to produce electricity.
Rotor: The blades and the hub together are called the rotor.
Tower: Towers are made from tubular steel (shown here) or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind", facing away from the wind.
Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Yaw motor: Powers the yaw drive.
                                                   
CONDITIONS OF THE OFFSHORE WIND ENERGY THE MOST INFLUENCIAL CONDITIONS
DENSITY (ρ)
Air more dense→more turbine energy
More air density on the sea
SWEPT AREA (A)
ROUGHNESS
less turbulences →more duration
Less roughness → less shearing
P ( W ) = ½ * ρ * A * V 3

5. CONDITIONS OF THE OFFSHORE WIND ENERGY THE MOST INFLUENCIAL CONDITIONS
                                                                                                                        
Wind Turbine Glossary
Anemometer: Measures the wind speed and transmits wind speed data to the controller.
Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
Brake: A disc brake which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat.
Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.
Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-speed shaft: Drives the generator.
Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Nacelle: The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician to stand inside while working.
Pitch: Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to produce electricity.
Rotor: The blades and the hub together are called the rotor.
Tower: Towers are made from tubular steel (shown here) or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind", facing away from the wind.
Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Yaw motor: Powers the yaw drive.
                                                   
CONDITIONS OF THE OFFSHORE WIND ENERGY THE MOST INFLUENCIAL CONDITIONS
P ( W ) = ½ * ρ * A * V 3
WIND SPEED (V)
Different parts
Is important to predict wind speed variations

6. CONDITIONS OF THE OFFSHORE WIND ENERGY THE MOST INFLUENCIAL CONDITIONS
                                                                                                                        
Wind Turbine Glossary
Anemometer: Measures the wind speed and transmits wind speed data to the controller.
Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
Brake: A disc brake which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat.
Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.
Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-speed shaft: Drives the generator.
Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Nacelle: The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician to stand inside while working.
Pitch: Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to produce electricity.
Rotor: The blades and the hub together are called the rotor.
Tower: Towers are made from tubular steel (shown here) or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind", facing away from the wind.
Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Yaw motor: Powers the yaw drive.
                                                   
CONDITIONS OF THE OFFSHORE WIND ENERGY THE MOST INFLUENCIAL CONDITIONS
EFFICIENCY
Maximum efficiency → 59%

7. FUNCTIONING OF OFFSHORE WIND TURBINES

8. HOW WIND TURBINES WORK THE MAIN COMPONENTS: Rotor = hub +blades
                                                                                                                        
Wind Turbine Glossary
Anemometer: Measures the wind speed and transmits wind speed data to the controller.
Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
Brake: A disc brake which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat.
Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.
Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-speed shaft: Drives the generator.
Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Nacelle: The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician to stand inside while working.
Pitch: Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to produce electricity.
Rotor: The blades and the hub together are called the rotor.
Tower: Towers are made from tubular steel (shown here) or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind", facing away from the wind.
Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Yaw motor: Powers the yaw drive.
                                                   
HOW WIND TURBINES WORK THE MAIN COMPONENTS: Rotor = hub +blades
A rotor: hub + 3 blades
Blades made of:
wood,
synthetic composites (polyester or epoxy reinforced by glass fibres),
metals (steel or aluminium alloys).
Blades length : between metres.
Source: www1.eere.energy.gov

9. HOW WIND TURBINES WORK THE MAIN COMPONENTS: Gear box, generator
                                                                                                                        
Wind Turbine Glossary
Anemometer: Measures the wind speed and transmits wind speed data to the controller.
Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
Brake: A disc brake which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat.
Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.
Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-speed shaft: Drives the generator.
Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Nacelle: The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician to stand inside while working.
Pitch: Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to produce electricity.
Rotor: The blades and the hub together are called the rotor.
Tower: Towers are made from tubular steel (shown here) or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind", facing away from the wind.
Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Yaw motor: Powers the yaw drive.
                                                   
HOW WIND TURBINES WORK THE MAIN COMPONENTS: Gear box, generator
Source: www1.eere.energy.gov
A gear box:
Connects the low-speed shaft to the high-speed shaft.
Raises the rotational speeds from about 30 to 60 rotations per minute to 1200 to 1500 rpm.
A three phase asynchronous generator:
Works with the wind turbine rotor which supplies very fluctuating mechanical power but at the output ensures that the output frequency is locked to that of the utility.
Sends the current through a transformer.
Source: js.efair.gov.cn
Source:

10. HOW WIND TURBINES WORK THE MAIN COMPONENTS: Yaw drive, tower
                                                                                                                        
Wind Turbine Glossary
Anemometer: Measures the wind speed and transmits wind speed data to the controller.
Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
Brake: A disc brake which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat.
Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.
Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-speed shaft: Drives the generator.
Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Nacelle: The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician to stand inside while working.
Pitch: Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to produce electricity.
Rotor: The blades and the hub together are called the rotor.
Tower: Towers are made from tubular steel (shown here) or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind", facing away from the wind.
Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Yaw motor: Powers the yaw drive.
                                                   
HOW WIND TURBINES WORK THE MAIN COMPONENTS: Yaw drive, tower
A yaw drive:
aligns the machine with the wind.
sensors activate the yaw control motor which rotates the turbine .
A tower:
Supports the nacelle assembly and elevates the rotor.
withstands significant loads, from gravitational, rotational and wind thrust loads
Its length is between meters.
Source: www1.eere.energy.gov

11. HOW WIND TURBINES WORK CONTROL SYSTEMS
                                                                                                                        
Wind Turbine Glossary
Anemometer: Measures the wind speed and transmits wind speed data to the controller.
Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
Brake: A disc brake which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat.
Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.
Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-speed shaft: Drives the generator.
Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Nacelle: The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician to stand inside while working.
Pitch: Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to produce electricity.
Rotor: The blades and the hub together are called the rotor.
Tower: Towers are made from tubular steel (shown here) or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind", facing away from the wind.
Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Yaw motor: Powers the yaw drive.
                                                   
HOW WIND TURBINES WORK CONTROL SYSTEMS
Control systems permit to start up when the wind speed is sufficient or to turn off the machine at about high speeds to prevent overheating of the generator.
We use a electronic controller which measures:
Voltage;
Current;
Frequency;
Temperature inside the nacelle;
Generator temperature;
Gear oil temperature;
Wind speed;
The direction of yawing;
Low-speed shaft rotational speed;
High-speed shaft rotational speed;

12. HOW WIND TURBINES WORK SAFETY SYSTEMS
                                                                                                                        
Wind Turbine Glossary
Anemometer: Measures the wind speed and transmits wind speed data to the controller.
Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
Brake: A disc brake which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat.
Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.
Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-speed shaft: Drives the generator.
Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Nacelle: The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician to stand inside while working.
Pitch: Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to produce electricity.
Rotor: The blades and the hub together are called the rotor.
Tower: Towers are made from tubular steel (shown here) or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind", facing away from the wind.
Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Yaw motor: Powers the yaw drive.
                                                   
HOW WIND TURBINES WORK SAFETY SYSTEMS
Source:web.abqtrib.com/art/news05
The first safety device is the vibration.It consists of a ball resting on a ring.
It’s important to stop automatically the wind turbine in case of dysfunction of a critical component.
we can use:
the aerodynamic braking system which consists in turning the rotor blades about 90 degrees.
The mechanical braking which is a disc brake placed on the gearbox high-speed shaft.

13. LOCATION AND ENVIRONMENTAL IMPACTS

14. LOCATION WHERE AND WITH WHAT MATERIALS?
The Department of Marine has indicated that a minimum distance of 5km offshore is appropriate
Wind turbines can be installed until several hundreds meters of deepth
MATERIALS:
Steel is more competitive than concrete
The metal parts of the turbine structures is specially coated to protect them from corrosion
the voltage of undersea cables can reach 150kV

15. LOCATION WHAT KIND OF FOUDATIONS?
Concrete or steel
3,5 to 4,5m of diameter

16. LOCATION WHAT KIND OF FOUNDATIONS?
Available for deep water

17. LOCATION WHAT KIND OF FOUNDATION?

18. THE ECONOMICAL ANALYSIS OF OFFSHORE WIND FARMS

19. Introduction
Offshore windpower as clean, free and renewable energy,most countries in world pay attention to it. Moreover,its capacity is huge.
Quantitative research and analysis for the technical and economic benefits of offshore windpower is an important topic. It is helpful to the rational use and development of offshore windpower.

20. A Initial Investment B Operating Costs C Total Revenue
a The costs of technical and economic feasibility study and design expenses
b The costs of offshore windpower turbine and transportation
c Foundation cost and installation cost
d The costs of grid connection
e Other cost
B Operating Costs
a The costs of materials (parts, lubricants, etc.)
b The operation and maintenance costs
c The management cost
d Power generation costs
C Total Revenue

21. Influencing factor of the costs
Distance to shore and water depth are one of the most important influencing factor on the cost of offshore windpower farms. It will affect foundation cost.

22. The calculation of economic analysis
NPV(Net Present Value): It refers to the difference of cost between the total output value and the current value of total value, in their effective use of n-year period.
Obviously, the NPV is below zero, and its economy is poor; NPV is zero, the inputs and outputs is same; NPV is above zero, its economy is good. The greater of its value, the better of its economy.
Net annual output value = Annual Production Value - Depreciation - Operating Expenses – Other Expenses

23. Depreciation: It is the loss of capital asserts
Depreciation: It is the loss of capital asserts. It is currency performance of the labor loss.
It can be simply expressed as:Dj = m*(P0 / n)
Dj——Depreciation of j year, j=1,2,3,…n , Depreciation Year.
P0——Costs per kilowatt
m——Total installed capacity

24. The conditons of this offshore windpower farm are as follows:
Example
The conditons of this offshore windpower farm are as follows:
Source:
Single capacity (kw)
Numbers
Height(m)
300 32 30
500 40 35
600 78
750 10 50

25. Total installed capacity: m = 8.39×104 kw
Costs per kilowatt: P0 = 9300 RMB/kw
Life-span : n = 20 year
Then: Depreciation
Dj = 9300×8.39×104/ =3.9×109RMB/Year

26. Costs Percentage (%) 82.6 6 4.8 6.6 100 Depreciation
Statistics of costs
Costs
Percentage (%)
Depreciation
82.6
The expenses of materials 6
The operation and maintenance expenses
4.8
The management expenses
6.6
Total
100
Source:

27. Therefore, the annual costs: 3.9×109/82.6% = 4721.5×108 RMB
Power Output of Last Year: 1.8×108 kwh
The Costs per kwh: ×104/1.8×108 = RMB

28. Some possible ways to reduce the costs of wind power
Increase single capacity and the turbine number of a offshore wind farm.
Reduce the cost per kilowatts.
Mass production can reduce unit cost.
Increase generating capacity
Reduce the development cost of electricity.
Reasonable protection to increase life span.

29. SOME COMPARISONS

30. Comparison of onshore and offshore wind power
Installed Cost
Offshore system is 30%--70% higher than onshore system
Efficiency
Offshore system is higher than onshore system
Wind speed
Higher in offshore
Life time
Offshore system has Longer life time
Installed capacity
Offshore is up to 50% more capacity
Environment impact
Offshore has less impact

31. Advantage Disadvantage Available of large continuous areas
Higher wind speeds, less turbulence,
Less environment impact
Disadvantage
High cost to set and maintain
Conditions are harsh and corrosive some time
Hard to reâir a broken down turbine in open watars

32. Wind power capacity of the world

33. Development of the wind energy over the world

34. Annual Wind Power Development

35. Wind power capacity of different countries

36. Installed wind power capacity per person in Europe

37. CONCLUSION

38. TACK SA MICKET!