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RENEWABLE ENERGY COURSE. Offshore Wind Turbines. The group: Pengmei WU Fan ZOU Aitor COLINAS Clément BERTRAND Loïc DELATTRE. October 2006. Supervisor : Prof Göran WALL. Summary. 1° CONDITIONS OF THE OFFSHORE WIND ENERGY 2° FUNCTIONING OF OFFSHORE WIND TURBINES 3° LOCATION
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RENEWABLE ENERGY COURSE Offshore Wind Turbines The group: Pengmei WU Fan ZOU Aitor COLINAS Clément BERTRAND Loïc DELATTRE October 2006 Supervisor: Prof Göran WALL
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
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
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
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%
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 WORKTHE 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 20- 60 metres. Source: www1.eere.energy.gov
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 WORKTHE 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:www.windmission.dk/workshop/ Source: js.efair.gov.cn
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 WORKTHE 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 30 - 80 meters. Source: www1.eere.energy.gov
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 WORKCONTROL 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;
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 WORKSAFETY 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: • theaerodynamic braking systemwhich consists in turning the rotor blades about 90 degrees. • The mechanical braking which is a disc brake placed on the gearbox high-speed shaft.
LOCATIONWHERE AND WITH WHAT MATERIALS? • WHERE: • 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
LOCATIONWHAT KIND OF FOUDATIONS? Concrete or steel 3,5 to 4,5m of diameter
LOCATIONWHAT KIND OF FOUNDATIONS? Available for deep water
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.
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.
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
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
Example • The conditons of this offshore windpower farm are as follows: • Source:http://www.dtzzfd.cn/fdxx.asp)
Total installed capacity: m = 8.39×104 kw • Costs per kilowatt: P0 = 9300 RMB/kw • Life-span : n = 20 year • Then: Depreciation • Dj = 9300×8.39×104/20 =3.9×109RMB/Year
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: 4721.5×104/1.8×108 = 0.262 RMB
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.
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
Advantage 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