This document provides an overview of wind energy projects and considerations for analysis. It discusses the key components of wind turbines and how wind energy can provide electricity on central grids, isolated grids and off grid. Some important factors for wind energy projects are having a good wind resource, environmental acceptability, grid interconnection and financing. The RETScreen model is introduced for analyzing energy production, costs and emissions reductions of wind energy projects worldwide using annual average data.
This document summarizes a seminar on wind power. It defines wind power as kinetic energy from wind that is converted into electrical energy using wind turbines. It describes the basic components and design considerations of wind turbines, including rotor size and generator size. The document discusses advantages such as being renewable and producing no pollution, and disadvantages such as wind strength varying and noise from turbines. It provides examples of large wind farms in the United States and typical costs to install wind turbines.
This document provides an overview of wind energy technology presented by Group 1. It discusses that wind energy is a renewable source that can be harnessed to generate power. The key components of a wind power system include wind turbines, generators, and control systems. Wind turbines convert the kinetic energy of wind into mechanical or electrical power. Modern wind turbines are primarily horizontal axis turbines that have blades, a gearbox, generator, and a nacelle housed at the top of a tower. The document also notes some benefits and limitations of wind power.
This document summarizes information about wind power. It discusses how wind is formed due to uneven heating of the Earth's surface creating low and high pressure regions. Wind power depends on wind speed, turbine availability, and turbine arrangement. There are two main types of wind power plants: on-shore and off-shore. On-shore plants have lower costs but off-shore plants access stronger winds. Wind turbines work by converting the kinetic energy of wind into rotational motion that spins a generator to produce electricity. The document also describes the different types of wind turbines, including horizontal axis wind turbines and vertical axis wind turbines, noting their various advantages and disadvantages.
Wind turbines convert the kinetic energy of the wind into mechanical power that can power homes and businesses. A wind turbine works opposite a fan, using wind to generate electricity rather than using electricity to create wind. The wind turns the turbine blades, which spin a shaft connected to a generator to produce electricity. Wind turbines are mounted on towers to reach stronger winds higher above the ground. Large wind farms with many turbines are built in consistently windy areas on land or offshore to provide power for thousands of homes.
This document discusses wind turbines and wind farms. It begins by explaining what wind is and the basic types of wind turbines, including horizontal axis and vertical axis turbines. It then discusses the major components of modern horizontal axis wind turbines. The document provides information on the top 10 wind power companies worldwide and lists the largest wind power plants, including the Alta Wind Energy Center in California, USA. It also discusses advantages and disadvantages of wind energy, as well as potential wind energy sites in the Philippines, including the Bangui Wind Farm in Ilocos Norte.
Wind farms consist of wind turbines that convert the kinetic energy of wind into electrical energy. Wind turbines work best in open, windy areas and use blades attached to a generator to harness the wind's movement and produce electricity. The generator is powered by the spinning blades, and the electricity is transmitted through a system that controls the constant movement of the blades.
This document provides an overview of wind energy projects and considerations for analysis. It discusses the key components of wind turbines and how wind energy can provide electricity on central grids, isolated grids and off grid. Some important factors for wind energy projects are having a good wind resource, environmental acceptability, grid interconnection and financing. The RETScreen model is introduced for analyzing energy production, costs and emissions reductions of wind energy projects worldwide using annual average data.
This document summarizes a seminar on wind power. It defines wind power as kinetic energy from wind that is converted into electrical energy using wind turbines. It describes the basic components and design considerations of wind turbines, including rotor size and generator size. The document discusses advantages such as being renewable and producing no pollution, and disadvantages such as wind strength varying and noise from turbines. It provides examples of large wind farms in the United States and typical costs to install wind turbines.
This document provides an overview of wind energy technology presented by Group 1. It discusses that wind energy is a renewable source that can be harnessed to generate power. The key components of a wind power system include wind turbines, generators, and control systems. Wind turbines convert the kinetic energy of wind into mechanical or electrical power. Modern wind turbines are primarily horizontal axis turbines that have blades, a gearbox, generator, and a nacelle housed at the top of a tower. The document also notes some benefits and limitations of wind power.
This document summarizes information about wind power. It discusses how wind is formed due to uneven heating of the Earth's surface creating low and high pressure regions. Wind power depends on wind speed, turbine availability, and turbine arrangement. There are two main types of wind power plants: on-shore and off-shore. On-shore plants have lower costs but off-shore plants access stronger winds. Wind turbines work by converting the kinetic energy of wind into rotational motion that spins a generator to produce electricity. The document also describes the different types of wind turbines, including horizontal axis wind turbines and vertical axis wind turbines, noting their various advantages and disadvantages.
Wind turbines convert the kinetic energy of the wind into mechanical power that can power homes and businesses. A wind turbine works opposite a fan, using wind to generate electricity rather than using electricity to create wind. The wind turns the turbine blades, which spin a shaft connected to a generator to produce electricity. Wind turbines are mounted on towers to reach stronger winds higher above the ground. Large wind farms with many turbines are built in consistently windy areas on land or offshore to provide power for thousands of homes.
This document discusses wind turbines and wind farms. It begins by explaining what wind is and the basic types of wind turbines, including horizontal axis and vertical axis turbines. It then discusses the major components of modern horizontal axis wind turbines. The document provides information on the top 10 wind power companies worldwide and lists the largest wind power plants, including the Alta Wind Energy Center in California, USA. It also discusses advantages and disadvantages of wind energy, as well as potential wind energy sites in the Philippines, including the Bangui Wind Farm in Ilocos Norte.
Wind farms consist of wind turbines that convert the kinetic energy of wind into electrical energy. Wind turbines work best in open, windy areas and use blades attached to a generator to harness the wind's movement and produce electricity. The generator is powered by the spinning blades, and the electricity is transmitted through a system that controls the constant movement of the blades.
This is enegy taken from the natural air!
Can you believe electricity being created because of air!
It is practiced on heights or near sea's.
Go ahead and enjoy!
Wind energy harnesses the kinetic energy of wind to generate electricity through wind turbines. Wind turbines convert the kinetic energy of the wind into mechanical power using propeller-like blades, which spin a shaft connected to a generator that produces electricity. The largest wind farms can have hundreds of turbines and generate terawatt-hours of electricity annually without carbon emissions. The leading countries for installed wind power capacity are China, United States, Germany, India and Spain.
WIND ENERGY (A SOURCE OF RENEWABLE ENERGY)Akhilesh Rai
Wind energy provides a clean, renewable source of electricity. Wind is caused by differences in the heating of the Earth's surface by the sun, which causes air to move from higher to lower pressure areas. The growth of wind energy has been driven by declining costs as turbine technology has advanced, with larger and more efficient turbines able to generate electricity for less than 5 cents per kWh. While wind farms can power many homes, their development requires consideration of potential impacts on property values, wildlife, and noise levels through proper siting.
- Wind power has increased significantly over the past few decades, growing from providing negligible amounts of energy in 1990 to becoming one of the fastest growing energy sources in the world by 2000.
- Technology has advanced from early drag-based designs to modern horizontal axis turbines that can be over 2 MW in size and achieve high capacity factors at optimal wind sites.
- The levelized cost of wind energy has declined significantly from over 12 cents/kWh in 1990 to around 3 cents/kWh for newer projects built in the 2000s, aided by technology improvements and policies like production tax credits.
The document provides information on wind energy, including:
1) It explains how wind is formed from differences in air temperatures and how this kinetic energy can be captured by wind turbines to generate electricity.
2) It discusses the history of wind power usage dating back thousands of years and the development of modern large-scale wind turbines in the late 19th century.
3) It notes the potential for wind power in the US, especially in the Dakotas and Texas, to generate enough electricity to power the entire country.
Wind energy is generated through wind turbines that convert the kinetic energy of wind into mechanical or electrical power. There are two main types of wind turbines - horizontal axis and vertical axis. Key components include blades, a drive train, a tower, and equipment to generate electricity. Multiple turbines grouped together form wind farms. Larger turbines can power many homes. While wind energy has environmental benefits over fossil fuels, it also has disadvantages such as intermittent supply and higher initial costs than other generation methods.
The document discusses wind energy and wind turbines. It begins by explaining that wind is caused by convection currents in the atmosphere driven by solar energy. It then classifies different types of winds and describes the Beaufort scale for measuring wind speed. The document focuses on horizontal axis wind turbines, describing their components, working principle, and equations of motion. It also discusses wind farms and criteria for selecting wind farm sites. Overall, the document provides an overview of wind energy production from atmospheric winds to powering wind turbines.
This presentation will describe the basics of wind power generation the technologies used in wind power. the energy conversion process used in wind power system are explained. This material was prepared for Debre Brihan Univesity 4th year power engineering students of 2017.
Wind energy is a variable resource that is difficult to integrate into electric grids due to its high variability and lack of correlation with demand. A study in Minnesota found that increasing wind penetration from 15-25% would increase costs to load by $2.11-$4.41/MWh due to balancing needs. The study also found that combining balancing areas and utilizing a wider geographic footprint reduced costs by making the wind output more stable. Significant transmission upgrades would be required to access the best wind resources.
Wind power works by using wind turbine blades to harness the kinetic energy of the wind. As the wind flows over the airfoil shaped blades, it causes them to spin an electric generator to produce electricity. There are two main types of wind turbines: horizontal-axis wind turbines that have three propeller-like blades and vertical-axis wind turbines that have blades arranged vertically like an eggbeater. Wind power is a renewable source that reduces greenhouse gas emissions and has grown significantly in India and worldwide in recent decades as the costs of production have decreased.
This document is a project report on wind power in India submitted by Agile Vinod Kumar Reddy in partial fulfillment of the requirements for a Bachelor of Technology degree. The report provides an overview of the history of wind energy use, how wind farms generate power, the technology behind wind turbines, advantages and limitations of wind farms, and India's potential and policies related to wind power. It discusses topics such as India's large wind resource, government support for the industry, capacity installed to date, and the role of wind power in addressing energy security, environmental, and economic issues in India.
Wind energy is created when air warmed by the sun rises, creating areas of lower pressure that are filled by cooler surrounding air rushing in, creating wind. Around 1-3% of the sun's energy hitting the Earth is converted to wind energy. Modern wind turbines are much more efficient than older designs, able to generate 10 times more power, and work by using wind to turn blades and spin a shaft connected to a generator to produce electricity. While a renewable source, wind energy is dependent on weather and wind conditions and may not always be cost competitive compared to other electricity sources.
Wind power harnesses the kinetic energy of wind to generate electricity. As wind moves over the Earth's surface, its motion can be captured by wind turbines to power generators. Modern wind turbines consist of blades attached to a rotor that spins a generator to produce electricity. Harnessing wind power provides a renewable and clean energy alternative to fossil fuels.
Wind power harnesses the kinetic energy of wind using wind turbines to generate mechanical or electrical power. It has several advantages over fossil fuels as it is a renewable resource that produces no greenhouse gases. While early windmills were used historically, modern utility-scale wind turbines are designed to optimize power extraction from the wind at a given location. Although wind power output can vary over time, wind energy represents an important source of renewable energy for many countries seeking to reduce reliance on fossil fuels.
Wind turbines convert the kinetic energy of wind into mechanical or electrical energy. Modern wind turbines are much more efficient than older designs, able to generate 250-300 kilowatts compared to older models generating around 30 kilowatts. Wind turbines work by using wind to turn blades which spin a shaft connected to a generator, producing electricity. They are mounted on towers to access stronger winds higher off the ground. While wind energy has advantages like being renewable and producing no emissions, it also has disadvantages like dependence on wind conditions and higher initial costs than some other energy sources.
The document discusses the generation of wind and factors that influence wind patterns such as uneven heating of the earth's surface and differences in land and water. It then covers Bernoulli's principle and how lift force is generated on airfoils in wind, allowing wind turbines to harness this force. The key types of wind turbines - horizontal axis and vertical axis - are compared in terms of their design, efficiency, and power output. The Betz limit for maximum theoretical power extraction from wind is derived based on kinetic energy equations. Challenges of new high altitude wind power concepts are also mentioned.
Wind power is boosting employment worldwide, with over 35,000 jobs now in the sector in Germany alone at manufacturing companies, component suppliers, project developers and operators. The rapid development of wind power is increasingly stimulating jobs markets, particularly in economically weak regions. By the end of last year, the wind power sector employed more than 35,000 people in Germany.
The document discusses the design and components of a wind turbine for power generation. It describes the key parts of a wind turbine including the generator, blades, hub, tower, and how it is connected to the electric grid. The generator converts the kinetic energy of the rotating blades into electrical energy. Blades are made of composite materials and their shape and count are optimized for aerodynamic efficiency. The tower needs to be tall to access stronger winds higher above the ground.
The document presents information on wind turbines, including:
- Definitions of wind turbines and their ability to convert kinetic wind energy to electrical power.
- A brief history of wind turbines from ancient Persia to the first electricity-generating turbines in the late 1800s.
- Descriptions of the two main types of wind turbines: horizontal-axis and vertical-axis.
- Examples of wind turbines on public display for education and demonstration purposes.
- Uses of small wind turbines for off-grid applications.
- Spacing considerations for wind turbines in farms.
- Current health monitoring techniques for wind turbines using sensors and imaging.
Wind energy is generated from wind turbines that convert the kinetic energy of wind into electrical energy. Leading wind turbine manufacturers include Vestas, GE, Siemens, and Gamesa. Countries leading in wind energy production are the US, Germany, Spain, China, and India. Government policies such as feed-in tariffs, tax incentives, and renewable portfolio standards affect the wind industry. Wind farms are operated by large utility companies and are sited based on wind resource maps and detailed site measurements.
This document summarizes different aspects of wind turbines. It discusses how wind power is calculated based on air density, swept area of the turbine, and wind speed. It describes the main types of wind turbines according to power output and design, including horizontal axis and vertical axis turbines. It also summarizes different blade configurations based on the number of blades and how blade design factors like twist and taper optimize power capture. Additionally, it outlines considerations for siting wind turbines and control mechanisms used in turbines of different sizes to regulate power in high winds.
This is enegy taken from the natural air!
Can you believe electricity being created because of air!
It is practiced on heights or near sea's.
Go ahead and enjoy!
Wind energy harnesses the kinetic energy of wind to generate electricity through wind turbines. Wind turbines convert the kinetic energy of the wind into mechanical power using propeller-like blades, which spin a shaft connected to a generator that produces electricity. The largest wind farms can have hundreds of turbines and generate terawatt-hours of electricity annually without carbon emissions. The leading countries for installed wind power capacity are China, United States, Germany, India and Spain.
WIND ENERGY (A SOURCE OF RENEWABLE ENERGY)Akhilesh Rai
Wind energy provides a clean, renewable source of electricity. Wind is caused by differences in the heating of the Earth's surface by the sun, which causes air to move from higher to lower pressure areas. The growth of wind energy has been driven by declining costs as turbine technology has advanced, with larger and more efficient turbines able to generate electricity for less than 5 cents per kWh. While wind farms can power many homes, their development requires consideration of potential impacts on property values, wildlife, and noise levels through proper siting.
- Wind power has increased significantly over the past few decades, growing from providing negligible amounts of energy in 1990 to becoming one of the fastest growing energy sources in the world by 2000.
- Technology has advanced from early drag-based designs to modern horizontal axis turbines that can be over 2 MW in size and achieve high capacity factors at optimal wind sites.
- The levelized cost of wind energy has declined significantly from over 12 cents/kWh in 1990 to around 3 cents/kWh for newer projects built in the 2000s, aided by technology improvements and policies like production tax credits.
The document provides information on wind energy, including:
1) It explains how wind is formed from differences in air temperatures and how this kinetic energy can be captured by wind turbines to generate electricity.
2) It discusses the history of wind power usage dating back thousands of years and the development of modern large-scale wind turbines in the late 19th century.
3) It notes the potential for wind power in the US, especially in the Dakotas and Texas, to generate enough electricity to power the entire country.
Wind energy is generated through wind turbines that convert the kinetic energy of wind into mechanical or electrical power. There are two main types of wind turbines - horizontal axis and vertical axis. Key components include blades, a drive train, a tower, and equipment to generate electricity. Multiple turbines grouped together form wind farms. Larger turbines can power many homes. While wind energy has environmental benefits over fossil fuels, it also has disadvantages such as intermittent supply and higher initial costs than other generation methods.
The document discusses wind energy and wind turbines. It begins by explaining that wind is caused by convection currents in the atmosphere driven by solar energy. It then classifies different types of winds and describes the Beaufort scale for measuring wind speed. The document focuses on horizontal axis wind turbines, describing their components, working principle, and equations of motion. It also discusses wind farms and criteria for selecting wind farm sites. Overall, the document provides an overview of wind energy production from atmospheric winds to powering wind turbines.
This presentation will describe the basics of wind power generation the technologies used in wind power. the energy conversion process used in wind power system are explained. This material was prepared for Debre Brihan Univesity 4th year power engineering students of 2017.
Wind energy is a variable resource that is difficult to integrate into electric grids due to its high variability and lack of correlation with demand. A study in Minnesota found that increasing wind penetration from 15-25% would increase costs to load by $2.11-$4.41/MWh due to balancing needs. The study also found that combining balancing areas and utilizing a wider geographic footprint reduced costs by making the wind output more stable. Significant transmission upgrades would be required to access the best wind resources.
Wind power works by using wind turbine blades to harness the kinetic energy of the wind. As the wind flows over the airfoil shaped blades, it causes them to spin an electric generator to produce electricity. There are two main types of wind turbines: horizontal-axis wind turbines that have three propeller-like blades and vertical-axis wind turbines that have blades arranged vertically like an eggbeater. Wind power is a renewable source that reduces greenhouse gas emissions and has grown significantly in India and worldwide in recent decades as the costs of production have decreased.
This document is a project report on wind power in India submitted by Agile Vinod Kumar Reddy in partial fulfillment of the requirements for a Bachelor of Technology degree. The report provides an overview of the history of wind energy use, how wind farms generate power, the technology behind wind turbines, advantages and limitations of wind farms, and India's potential and policies related to wind power. It discusses topics such as India's large wind resource, government support for the industry, capacity installed to date, and the role of wind power in addressing energy security, environmental, and economic issues in India.
Wind energy is created when air warmed by the sun rises, creating areas of lower pressure that are filled by cooler surrounding air rushing in, creating wind. Around 1-3% of the sun's energy hitting the Earth is converted to wind energy. Modern wind turbines are much more efficient than older designs, able to generate 10 times more power, and work by using wind to turn blades and spin a shaft connected to a generator to produce electricity. While a renewable source, wind energy is dependent on weather and wind conditions and may not always be cost competitive compared to other electricity sources.
Wind power harnesses the kinetic energy of wind to generate electricity. As wind moves over the Earth's surface, its motion can be captured by wind turbines to power generators. Modern wind turbines consist of blades attached to a rotor that spins a generator to produce electricity. Harnessing wind power provides a renewable and clean energy alternative to fossil fuels.
Wind power harnesses the kinetic energy of wind using wind turbines to generate mechanical or electrical power. It has several advantages over fossil fuels as it is a renewable resource that produces no greenhouse gases. While early windmills were used historically, modern utility-scale wind turbines are designed to optimize power extraction from the wind at a given location. Although wind power output can vary over time, wind energy represents an important source of renewable energy for many countries seeking to reduce reliance on fossil fuels.
Wind turbines convert the kinetic energy of wind into mechanical or electrical energy. Modern wind turbines are much more efficient than older designs, able to generate 250-300 kilowatts compared to older models generating around 30 kilowatts. Wind turbines work by using wind to turn blades which spin a shaft connected to a generator, producing electricity. They are mounted on towers to access stronger winds higher off the ground. While wind energy has advantages like being renewable and producing no emissions, it also has disadvantages like dependence on wind conditions and higher initial costs than some other energy sources.
The document discusses the generation of wind and factors that influence wind patterns such as uneven heating of the earth's surface and differences in land and water. It then covers Bernoulli's principle and how lift force is generated on airfoils in wind, allowing wind turbines to harness this force. The key types of wind turbines - horizontal axis and vertical axis - are compared in terms of their design, efficiency, and power output. The Betz limit for maximum theoretical power extraction from wind is derived based on kinetic energy equations. Challenges of new high altitude wind power concepts are also mentioned.
Wind power is boosting employment worldwide, with over 35,000 jobs now in the sector in Germany alone at manufacturing companies, component suppliers, project developers and operators. The rapid development of wind power is increasingly stimulating jobs markets, particularly in economically weak regions. By the end of last year, the wind power sector employed more than 35,000 people in Germany.
The document discusses the design and components of a wind turbine for power generation. It describes the key parts of a wind turbine including the generator, blades, hub, tower, and how it is connected to the electric grid. The generator converts the kinetic energy of the rotating blades into electrical energy. Blades are made of composite materials and their shape and count are optimized for aerodynamic efficiency. The tower needs to be tall to access stronger winds higher above the ground.
The document presents information on wind turbines, including:
- Definitions of wind turbines and their ability to convert kinetic wind energy to electrical power.
- A brief history of wind turbines from ancient Persia to the first electricity-generating turbines in the late 1800s.
- Descriptions of the two main types of wind turbines: horizontal-axis and vertical-axis.
- Examples of wind turbines on public display for education and demonstration purposes.
- Uses of small wind turbines for off-grid applications.
- Spacing considerations for wind turbines in farms.
- Current health monitoring techniques for wind turbines using sensors and imaging.
Wind energy is generated from wind turbines that convert the kinetic energy of wind into electrical energy. Leading wind turbine manufacturers include Vestas, GE, Siemens, and Gamesa. Countries leading in wind energy production are the US, Germany, Spain, China, and India. Government policies such as feed-in tariffs, tax incentives, and renewable portfolio standards affect the wind industry. Wind farms are operated by large utility companies and are sited based on wind resource maps and detailed site measurements.
This document summarizes different aspects of wind turbines. It discusses how wind power is calculated based on air density, swept area of the turbine, and wind speed. It describes the main types of wind turbines according to power output and design, including horizontal axis and vertical axis turbines. It also summarizes different blade configurations based on the number of blades and how blade design factors like twist and taper optimize power capture. Additionally, it outlines considerations for siting wind turbines and control mechanisms used in turbines of different sizes to regulate power in high winds.
Wind turbines convert the kinetic energy of wind into mechanical energy using rotor blades, a shaft, and a generator. As wind passes through rotor blades, lift and drag forces cause them to spin, transferring mechanical energy to the generator via the shaft. Within the generator, this mechanical energy is converted into electrical energy via electromagnetic induction. Additional gearing is often used to increase the rotor shaft's RPM to a rate suitable for efficient electricity production. Horizontal axis wind turbines also use yaw systems to face rotor blades into the wind for maximum energy capture as wind direction changes. Braking mechanisms limit blade speed during high winds to prevent equipment damage.
The Egyptians were the first to use wind power around 3,500 BC by creating sails for boats. In 500 BC, Persians developed the first wind-powered device to grind grain. Between 1300-1850 AD, familiar windmill designs spread across Europe to mill grain on a large scale. In the late 1800s and early 1900s, early electric wind turbines were developed in Scotland and the US. Throughout the 1900s, wind turbines increased in size and efficiency and became more widely used globally to generate electricity, with global capacity growing from under 20,000 MW in 1990 to over 486,000 MW by 2016.
Utilization Of Hybrid PV-Wind Energy SystemGOURAB SARKAR
The document summarizes a seminar presentation on utilizing hybrid PV-wind energy systems. It discusses how hybrid systems combine solar and wind power to provide reliable energy. It describes the components of a hybrid system, including PV panels, wind turbines, batteries, inverters, and controllers. The document outlines the advantages of hybrid systems in providing sustainable energy without pollution for powering homes, villages and other remote locations off the main grid. It concludes that the combination of solar and wind resources performs better than either technology alone due to their complementary seasonal profiles.
Presentation About Designing A Simple Windmill For Generation Of Electricity At A Very Small-scale ... (Download It To Get More Out Of It: Animations Don't Work In Preview) ... !
The document discusses wind power and wind turbines. It explains that wind is created by uneven heating of the earth's surface, and the power of wind is determined by air density, rotor area, and wind speed. There are two main types of wind turbines: horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT). HAWTs are the most common and can have one, two, or three blades mounted on an axis parallel to the ground and to the wind flow. VAWTs have vertical axes and either a Savonius S-shaped design or a Darrieus eggbeater shape. Both turbine types use rotating blades connected to a generator to convert kinetic wind energy into electrical energy.
The document discusses integrated wind energy storage solutions presented by Milesh Gogad of GE Renewables at a conference in New Delhi. It outlines key applications of energy storage with wind power, including providing predictable power output and allowing greater utilization of wind power. The presentation describes GE's integrated solution using battery storage, control software and remote monitoring to enable various benefits like improved revenue streams and grid support. It also demonstrates three software applications for energy storage integrated with wind farms that provide predictable power output, frequency regulation and ramp control capabilities.
The document discusses the use of magnetic levitation for wind turbines. It begins with an overview of wind energy and the increasing global demand for electricity. It then describes how magnetic levitation wind turbines work, including their vertical axis design and use of permanent magnets to levitate and spin the turbine with minimal friction. Benefits include higher efficiency, ability to operate in lower winds, reduced maintenance needs compared to traditional horizontal axis turbines. Applications include use in urban areas and remote locations not suited for large conventional turbines. Overall, the document provides an introduction to magnetic levitation wind turbines and their advantages over traditional horizontal axis designs.
Wind turbines convert the kinetic energy of wind into mechanical or electrical energy. They consist of a tower, nacelle, rotor blades, generator, and other components. When wind blows, the rotor blades spin a shaft connecting to a generator inside the nacelle to produce electricity. Wind turbines require a minimum wind speed of 10-15 kph to function and automatically stop at 90 kph for safety. They come in both onshore and offshore varieties, with offshore turbines able to generate more electricity due to more regular winds but being more expensive to install and maintain.
This document discusses renewable energy resources, specifically wind energy technology. It provides information on wind power potential in India, the evolution of wind turbines from ancient uses to modern electricity generation, types of wind turbines including horizontal axis and vertical axis designs, key components of wind turbines like blades and towers, and advantages and disadvantages of wind power. Key points covered include India's wind power potential of 46,092 MW, the declining costs of wind energy production from 1979 to 2012, and how wind farms are needed to provide electricity at utility scales.
The document discusses vertical axis wind turbines (VAWT) as an option for residential wind power generation. It provides information on several VAWT models available ranging from 500W to 20,000W capacity. State rebates of 30-60% are available in California, New Jersey, and New York to help reduce the cost of installing a VAWT. VAWTs have advantages over traditional horizontal axis turbines for residential use, such as being lower profile and able to generate power from any wind direction.
Wind energy has a long history dating back thousands of years. Modern utility-scale wind turbines are much larger than early designs and can power hundreds of homes. While wind is a renewable resource, it fluctuates and is not a constant power source. Wind farms are best used alongside other renewable energy sources. Technological advances continue to be made to optimize wind energy production and integrate it into energy systems.
The objective of this project is to design a wind turbine that is optimized for the constraints that come with residential use. The main tasks of this project are:
> To study the design process and methodology of wind turbine
> Derive the Blade Element Momentum (BEM) theory then use it to conduct a parametric study that will determine if the optimized values of blade pitch and chord length create the most efficient blade geometry
> Analyse different air-foils to determine which one creates the most efficient wind turbine blade.
Nwtc seminar overview of the impact of turbulence on turbine dynamics, sept...ndkelley
Overview presentation on the impact of atmospheric turbulence on the dynamic response of wind turbines derived from 20 years of research at the National Renewable Energy Laboratory.
The stable atmospheric boundary layer a challenge for wind turbine operatio...ndkelley
An overview presentation of the impact and challenge of the stable atmospheric boundary layer on wind turbine dynamics presented to AGU Fall Meeting 2008
1115161Wind Power Now, Tomorrow C.P. (Case) .docxpaynetawnya
11/15/16
1
Wind Power:
Now, Tomorrow
C.P. (Case) van Dam
EME-1
Mechanical Engineering
November 14, 2016
How does it function?
11/15/16
2
Wind Turbine Power
• The amount of power generated by a turbine depends on the power in
the wind and the efficiency of the turbine:
• Power in wind
• Efficiency or Power Coefficient, Cp:
– Rotor (Conversion of wind power to mechanical power)
– Gearbox (Change in rpm)
– Generator & Inverter (Conversion of mechanical power to electrical power)
Power
Turbine
!
"#
$
%&
=
Efficiency
Factor
!
"#
$
%&
×
Power
Wind
!
"#
$
%&
P
w
= 1
2
ρA
d
V
w
3
Basic Rotor Performance
(Momentum Theory)
Wind speed, Vw
Air density, ρ
Disk area, Ad
Power in wind, Pw = 1/2 ρ Vw3 Ad
Maximum rotor power, P = 16/27 Pw
Rotor efficiency, Cp = P / Pw
Betz limit, max Cp = 16/27 = 59.3%
11/15/16
3
Region 4
• Region 1
Turbine is stopped or
starting up
• Region 2
Efficiency maximized
by maintaining
optimum rotor RPM
(for variable speed
turbine)
• Region 3
Power limited through
blade pitch
• Region 4
Turbine is stopped
due to high winds
(loads)
HAWT Power Characteristics
Johnson et al (2005)
• Peak Cp at TSR = 9
• This Cp is maintained in Region II of power curve by controlling rotor RPM
• In Region III power is controlled by changing blade pitch.
HAWT Cp-TSR Curve
Jackson (2005)
11/15/16
4
• Cp = Protor / (1/2 ρ Vw3 Ad)
• Solidity = Blade Area / Ad
• TSR = Tip Speed / Vw
• High power efficiency for
rotors with low solidity and
high TSR
• Darrieus (VAWT) is less
efficient than HAWT
Efficiency of Various Rotor
Designs
Butterfield (2008)
Cp
Tip Speed Ratio TSR = π D RPM / (60 Vw)
kidwind.org
C.P. van Dam
Dutch Mill
16th century
Water pumping, Grinding materials/grain
W. Gretz, DOE/NREL
Persian grain mill
9th century
American Multi-blade
19th century
Water pumping - irrigation
Brush Mill
1888
First wind turbine
12 kW
17 m rotor diameter
Charles F. Brush Special Collection,
Case Western Reserve University
telos.net/wind
Gedser Mill
1956, Denmark
Forerunner to modern wind
turbines
11/15/16
5
Evolution of U.S. Utility-Scale
Wind Turbine Technology
NREL
Wind Turbine Scale-Up and Impact on Cost
U.S. DOE, Wind Vision, March 2015
• Scale-up has been effective in reducing cost but uncertain if this trend can continue
11/15/16
6
Modern Wind
Turbines
• 1.0-3.0 MW
• Wind speeds: 3-25 m/s
– Rated power at 11-12 m/s
• Rotor
– Lift driven
– 3 blades
– Upwind
– Full blade pitch
– 70–120 m diameter
– 5-20 RPM
– Fiberglass, some carbon fiber
• Active yaw
• Steel tubular tower
• Installed in plants/farms of 100-200 MW
• ~40% capacity factor
– 1.5 MW wind turbine would generate
about 5,250,000 kWh per year
– Average household in California uses
about 6,000 kWh per year
Vestas
V90-3.0
MW
11/15/16
7
Technical Specificat ...
This document provides an overview of wind energy and the wind industry in Quebec and Canada. It discusses the basics of how wind is generated and how that kinetic energy is captured by wind turbines to generate electricity. It describes the major components of modern wind turbines, including foundations, towers, nacelles, rotors, and hubs. The document outlines how wind farms are constructed and how the electricity is integrated into the grid. It also addresses the intermittency of wind and how geographical dispersion of turbines can help reduce variability. The document reviews environmental permitting requirements and potential impacts of wind projects as well as life cycle analyses. It provides details on the Vents du Kempt wind farm project in Quebec and discusses future plans for wind development in
Vortex bladeless wind energy works by maximizing vortex shedding from a vertical mast to generate electricity. As wind flows past the mast, vortices are shed at specific frequencies depending on wind speed. The mast oscillates from the vortex shedding, and this kinetic energy is converted to electricity by a generator located at the base. Vortex bladeless has advantages over traditional wind turbines in that it has no moving parts high above the ground, is more bird-friendly, and can operate at lower wind speeds. While efficiency can be improved, it provides an innovative new approach to harnessing wind power without blades.
Renewable energy technologies and their potentialRahul Gupta
The document discusses various renewable energy technologies and their potential. It describes renewable energy as energy sources that are naturally replenished and exist perpetually in the environment. The major renewable sources mentioned are wind energy, solar energy, biomass energy, hydro energy, and geothermal energy. For wind energy, it discusses how wind turbines work to convert kinetic wind energy into electrical energy. It also provides details on solar thermal and photovoltaic technologies to harness solar energy. Overall, the document outlines the working and status of different renewable sources with the aim to highlight their significant potential to provide clean and sustainable energy.
The document summarizes a feasibility study conducted by the US Army Corps of Engineers to develop renewable energy at a military training complex in Afghanistan. It assessed various renewable technologies including wind turbines, solar PV, solar hot water, and lighting retrofits. Due to logistical and maintenance challenges, larger wind turbines and solar arrays were deemed too difficult and smaller, distributed systems were recommended instead. Contractors in Kabul could install and maintain the proposed smaller systems. The study also considered energy efficiency upgrades and conducted site assessments to identify the best locations for wind turbines.
INTRODUCTION wind energy and its type .pptxmansi21bphn002
The document provides an overview of wind energy, including its history, how it works, applications, and future goals. It discusses how wind is naturally produced and how wind turbines convert kinetic wind energy into electrical energy. The history section outlines key developments in wind power technology from the 1900s to present day. It also describes different types of wind turbines and generators. The document concludes by stating that ongoing innovations aim to improve wind turbine efficiency and integration with other renewable technologies to provide a more reliable energy supply and contribute to a sustainable future.
Excipio Energy offshore renewables 2016Roy Robinson
Excipio Energy aims to harness offshore renewable energy, starting with steady ocean currents in the Gulf of Mexico using existing oil and gas infrastructure. Its mission is to make offshore renewable energy the most profitable, safe and reliable global energy source. It plans to initially generate power from ocean currents and later expand to technologies like offshore wind, waves and OTEC. Excipio believes offshore renewable platforms can serve as bases for aquaculture and research while avoiding many risks associated with oil and gas extraction.
This document provides an overview of wind energy and wind turbines. It discusses the advantages of wind energy such as being clean and having an abundant domestic source. It also discusses disadvantages like intermittency and land use impacts. The document describes different types of wind turbines including horizontal and vertical axis designs. It provides information on wind resources and wind power potential in the United States. Key concepts in wind turbine operation and aerodynamics are explained like Betz's law. Cost trends for wind power and the future outlook of the industry are also summarized.
IRJET - Design & Construction of Combined Axis Wind Turbine with Solar Power ...IRJET Journal
This document describes the design and construction of a combined horizontal and vertical axis wind turbine with solar panels. It begins with an introduction to renewable energy sources and the benefits of wind and solar power. It then provides details on the components and operation of horizontal axis wind turbines, followed by vertical axis wind turbines. The materials and components used in this combined design are outlined. Diagrams and tables showing the setup and power generated from each energy source are included. The conclusions discuss the results and benefits of generating clean electricity from renewable wind and solar energy.
Nwtc turb sim workshop september 22 24, 2008- site specific modelsndkelley
1) The document describes several inflow turbulence models available in the TurbSim code developed by NREL, including models based on standard IEC conditions, smooth homogeneous terrain, specific wind farm sites, complex mountainous terrain, and a North American high plains site.
2) Comparisons of simulation results using the IEC, Great Plains, and NWTC models show differences in predicted blade loads, rotor torque, bending moments and tip deflections when applied to the NREL 5 MW reference turbine.
3) In particular, the Great Plains model including a low-level jet produced significantly higher loads and deflections compared to the standard IEC model, demonstrating the importance of using site-specific models.
Engineering challenges for future wind energy development, 11th h.t. person l...ndkelley
The document discusses engineering challenges for future wind energy development. It outlines goals of providing 20% of US electricity from wind by 2030, but barriers like transmission, resource assessment accuracy, and turbine response to turbulence must be overcome. Key challenges are understanding turbulence's impact on turbine loads, collaborating with meteorologists on wind forecasts, and developing offshore wind platforms and solutions for the complex offshore environment. Success will require a multidisciplinary approach across engineering and atmospheric science.
This document proposes developing offshore wind farms in the Persian Gulf, Oman Sea, and Caspian Sea based on an analysis of wind data from locations in those areas. It finds that the Persian Gulf is strongly recommended for offshore wind farms due to minimum wind speed requirements being met. The Oman Sea needs further investigation as wind speeds were slightly above minimum requirements. The Caspian Sea is not recommended due to low wind speeds below minimum requirements and high installation costs. It provides an overview of offshore wind farm components and engineering aspects like tower design and relationship between wind speed and power extraction.
This document proposes a high-return-on-investment wind turbine design that eliminates the need for expensive yaw systems, brakes, and foundations. It would utilize ultra-high lift airfoils optimized for moderate wind speeds and constant cross-section blades that can be mass produced. Initial funding is requested to build 10 pre-production prototypes to test in various locations and demonstrate the viability of the simplified, lower-cost design. The goal is to produce a turbine that pays for itself in under 10 years without subsidies by targeting markets with consistent moderate winds.
Caddo Wind Virtual Public Meeting PresentationHeritage Wind
Apex Clean Energy is developing a large portfolio of wind energy projects across the US with over 12,000 MW of capacity. They have assembled the largest wind development pipeline in the country. Apex carefully selects project locations based on wind resource, transmission access, and permitting constraints. Their team of over 230 professionals manages projects from site selection through construction. Apex was formed in 2009 and has experience developing over $10 billion of renewable energy facilities. They currently have several operating wind projects in Texas, Illinois, Oklahoma, and other states.
PV Navigator develops utility-scale solar installations on closed landfills and brownfield sites. It has developed approximately 50 MW of capacity across various sites on the east and west coasts of the United States. The company focuses on smaller 1-10 MW distributed projects that can rapidly deliver power to meet renewable energy standards. Key challenges for landfill solar projects are obtaining permits and power purchase agreements that make the economics work.
Communications Mining Series - Zero to Hero - Session 1DianaGray10
This session provides introduction to UiPath Communication Mining, importance and platform overview. You will acquire a good understand of the phases in Communication Mining as we go over the platform with you. Topics covered:
• Communication Mining Overview
• Why is it important?
• How can it help today’s business and the benefits
• Phases in Communication Mining
• Demo on Platform overview
• Q/A
GraphSummit Singapore | The Art of the Possible with Graph - Q2 2024Neo4j
Neha Bajwa, Vice President of Product Marketing, Neo4j
Join us as we explore breakthrough innovations enabled by interconnected data and AI. Discover firsthand how organizations use relationships in data to uncover contextual insights and solve our most pressing challenges – from optimizing supply chains, detecting fraud, and improving customer experiences to accelerating drug discoveries.
TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
- The top challenges for privacy leaders, practitioners, and organizations in 2024
- Key themes to consider in developing and maintaining your privacy program
Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
At WSTS 2024, Alon Stern explored the topic of parametric holdover and explained how recent research findings can be implemented in real-world PNT networks to achieve 100 nanoseconds of accuracy for up to 100 days.
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
Goodbye Windows 11: Make Way for Nitrux Linux 3.5.0!SOFTTECHHUB
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The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
Essentials of Automations: The Art of Triggers and Actions in FMESafe Software
In this second installment of our Essentials of Automations webinar series, we’ll explore the landscape of triggers and actions, guiding you through the nuances of authoring and adapting workspaces for seamless automations. Gain an understanding of the full spectrum of triggers and actions available in FME, empowering you to enhance your workspaces for efficient automation.
We’ll kick things off by showcasing the most commonly used event-based triggers, introducing you to various automation workflows like manual triggers, schedules, directory watchers, and more. Plus, see how these elements play out in real scenarios.
Whether you’re tweaking your current setup or building from the ground up, this session will arm you with the tools and insights needed to transform your FME usage into a powerhouse of productivity. Join us to discover effective strategies that simplify complex processes, enhancing your productivity and transforming your data management practices with FME. Let’s turn complexity into clarity and make your workspaces work wonders!
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Mike Del Balso, CEO & Co-Founder at Tecton, presents "Full RAG," a novel approach to AI recommendation systems, aiming to push beyond the limitations of traditional models through a deep integration of contextual insights and real-time data, leveraging the Retrieval-Augmented Generation architecture. This talk will outline Full RAG's potential to significantly enhance personalization, address engineering challenges such as data management and model training, and introduce data enrichment with reranking as a key solution. Attendees will gain crucial insights into the importance of hyperpersonalization in AI, the capabilities of Full RAG for advanced personalization, and strategies for managing complex data integrations for deploying cutting-edge AI solutions.
Maruthi Prithivirajan, Head of ASEAN & IN Solution Architecture, Neo4j
Get an inside look at the latest Neo4j innovations that enable relationship-driven intelligence at scale. Learn more about the newest cloud integrations and product enhancements that make Neo4j an essential choice for developers building apps with interconnected data and generative AI.
Unlock the Future of Search with MongoDB Atlas_ Vector Search Unleashed.pdfMalak Abu Hammad
Discover how MongoDB Atlas and vector search technology can revolutionize your application's search capabilities. This comprehensive presentation covers:
* What is Vector Search?
* Importance and benefits of vector search
* Practical use cases across various industries
* Step-by-step implementation guide
* Live demos with code snippets
* Enhancing LLM capabilities with vector search
* Best practices and optimization strategies
Perfect for developers, AI enthusiasts, and tech leaders. Learn how to leverage MongoDB Atlas to deliver highly relevant, context-aware search results, transforming your data retrieval process. Stay ahead in tech innovation and maximize the potential of your applications.
#MongoDB #VectorSearch #AI #SemanticSearch #TechInnovation #DataScience #LLM #MachineLearning #SearchTechnology
Programming Foundation Models with DSPy - Meetup SlidesZilliz
Prompting language models is hard, while programming language models is easy. In this talk, I will discuss the state-of-the-art framework DSPy for programming foundation models with its powerful optimizers and runtime constraint system.
Climate Impact of Software Testing at Nordic Testing DaysKari Kakkonen
My slides at Nordic Testing Days 6.6.2024
Climate impact / sustainability of software testing discussed on the talk. ICT and testing must carry their part of global responsibility to help with the climat warming. We can minimize the carbon footprint but we can also have a carbon handprint, a positive impact on the climate. Quality characteristics can be added with sustainability, and then measured continuously. Test environments can be used less, and in smaller scale and on demand. Test techniques can be used in optimizing or minimizing number of tests. Test automation can be used to speed up testing.
AI 101: An Introduction to the Basics and Impact of Artificial IntelligenceIndexBug
Imagine a world where machines not only perform tasks but also learn, adapt, and make decisions. This is the promise of Artificial Intelligence (AI), a technology that's not just enhancing our lives but revolutionizing entire industries.
Sudheer Mechineni, Head of Application Frameworks, Standard Chartered Bank
Discover how Standard Chartered Bank harnessed the power of Neo4j to transform complex data access challenges into a dynamic, scalable graph database solution. This keynote will cover their journey from initial adoption to deploying a fully automated, enterprise-grade causal cluster, highlighting key strategies for modelling organisational changes and ensuring robust disaster recovery. Learn how these innovations have not only enhanced Standard Chartered Bank’s data infrastructure but also positioned them as pioneers in the banking sector’s adoption of graph technology.
Wind energy applications, ams short course, august 1, 2010, keystone, co
1. NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
Boundary Layer Turbulence and Turbine
Interactions with a Historical Perspective
AMS Short Course:
Wind Energy Applications,
Supported by Atmospheric
Boundary Layer Theory,
Observations, and Modeling
Keystone, Colorado
Neil D. Kelley
National Wind Technology Center
August 1, 2010
Innovation for Our Energy Future
2. Innovation for Our Energy Future
Outline
2
• Background
• Lecture objective
• Collecting turbulence-turbine interaction data
• Interpreting the results
• Understanding the impact of turbulence on turbine
structural components
• The role of the stable boundary layer
• Conclusions
• For more information
• A discussion question
3. Innovation for Our Energy Future
Background
3
• Wind energy technology was resurrected in the U.S. in the
early 1970s
• After initially being established at the National Science
Foundation, the Federal Wind Program was located in
what became the U.S. Department of Energy
• The Federal Wind Program had four major components:
utility-scale turbine development, small turbine
development, vertical axis turbine development, and
resource assessment
• The utility-scale program was managed by NASA for the
U.S.DOE with prototype turbines built by several
contractors between 1975 and 1985.
4. Innovation for Our Energy Future
200 kW
600 kW
2000 kW
2500 kW
3200 kW
4000 kW
Capacity Evolution of Federal Wind Program Turbines
1975-1985
5. Innovation for Our Energy Future
Hamilton-
Standard
BoeingBoeingGeneral
Electric
Westinghouse Boeing
Rotor Diameter and Hub Height Evolution
latest
generation
turbine
hub height
range
6. Innovation for Our Energy Future
California Experience
6
Tehachapi Pass
Altamont Pass
San Gorgonio Pass
(Palm Springs)
7. Innovation for Our Energy Future
The Turbine Operating Situation in the mid 1980’s
7
In California:
• Significant number
of equipment
failures
• Poor performance
due in part to the
high density of
turbines
In Hawaii:
• High maintenance costs and
poor availability for
Westinghouse turbines on
Oahu
• Poor performance of wind
farms on the Island of Hawaii
8. Innovation for Our Energy Future
Hawaiian Experience
8
• 15 Westinghouse 600 kW Turbines 1985-1996
• DOE/NASA 3.2 MW Boeing MOD-5B Prototype
1987-1993
• Installed on complex uphill terrain at Kuhuku
Point with predominantly upslope, onshore flow
but occasionally experienced downslope flows
(Kona Winds)
• Chronic underproduction relative to projections
for both turbine designs
• Significant numbers of faults and failures
occurred during the nighttime hours
particularly on the Westinghouse turbines.
• Serious loading issues with the MOD-5B during
Kona Winds required the turbine to be locked
out because of excessive vibrations generated
within the turbine structure
Oahu
Westinghouse 600 kW
MOD-5B
9. Innovation for Our Energy Future
Hawaiian Experience – cont’d
9
• 81 Jacobs 17.5 and 20 kW
turbines installed downwind of
a mountain pass on the Kahua
Ranch 1985-
• Wind technicians reported in
1986 a significant number of
failures that occurred
exclusively at night
• At some locations turbines
could not be successfully
maintained downwind of local
terrain features and were
abandoned
Hawaii
10. Innovation for Our Energy Future
Results . . .
10
• None of the large, multi-megawatt turbine prototypes reached
full production status
• Post analysis revealed that the structural fatigue damage to
these machines far exceeded the original design estimates in
virtually all cases
• These excessive loads were attributed to atmospheric
turbulence
• In the late 1980’s and early 1990’s the industry concentrated on
the development wind farms employing large numbers of
turbines in the 25 to 200 kW range
11. Innovation for Our Energy Future
The Payoff in California . . .
11
Year
1985 1990 1995 2000 2005
RegionalCapacityfactor(%)
0
10
20
30
40
50
60
Altamont
Tehachapi
San Gorgonio
Year
1985 1990 1995 2000 2005
RegionalCapacityfactor(%)
0
10
20
30
40
50
60
Altamont
Tehachapi
San Gorgonio
Source: California Energy Commission
Annual Average
Q2 & Q3 Average (Wind Season)
Range of Current
Capacity Factors
In the U.S.
There have been incremental
improvements in the California
wind farm Capacity Factor
performance in the early 1990s
and again beginning in about
2000. This has been largely the
result of installation of more
reliable and efficient turbines.
12. Innovation for Our Energy Future
Today
12
• The U.S. has the greatest installed wind energy capacity in
the world
• New turbine designs are now reaching the capacities of the
1970-1980 prototypes once again and are beginning to
surpass them
• New turbines are being designed to capture energy from
lower wind resource sites which increases their rotor
diameters and hub heights
• The new machines are being constructed of lighter and
stronger materials in order to reduce the cost of energy but
they are also more dynamically active.
13. Innovation for Our Energy Future
Current Evolution of U.S. Commercial Wind Technology
13
14. Innovation for Our Energy Future
However There is a Down Side . . .
• The aggregate performance of currently operating wind U.S. wind farms has
been estimated to be in the neighborhood of 10% below project design
estimates
• Maintenance and operations (M&O) costs are seen as approaching equivalency
with the production tax credit
• Both are major contributors to a continuance of a higher than the targeted Cost
of Energy (COE)
10% Wind Farm Power
Underproduction & Possible Sources
Source: American Wind Energy Association
$
High Maintenance & Repair Costs Contribution to M&O
Expected annual M&R costs over a 20 year turbine lifetime
Courtesy: Matthias Henke, Lahmeyer International
presented at Windpower 2008
used with permission
15. Innovation for Our Energy Future
An Interpretation . . .
15
$
Turbines, as designed, are not
compatible with their operating
environments
This incompatibility manifests
itself as increasing cumulative
costs as the turbines age
• We believe atmospheric turbulence continues to
play a major role in this incompatibility
• The larger and more flexible turbines being
designed and installed today when coupled with a
much different atmospheric operating environment
at these heights are being challenged
• We will now overview our research into the effects
of turbulence on wind turbines conducted over the
past 20 years
16. Innovation for Our Energy Future
Lecture Objective
16
To provide a summary and overview of the
results of research into the effects of boundary
layer turbulence on wind turbines in order to
inform boundary layer meteorologists about how
wind energy technology is dependent on their
knowledge and understanding.
17. Innovation for Our Energy Future
Research Approach
17
Make simultaneous, detailed measurements of both the turbulent
inflow and the corresponding turbine response!
Interpret the results in terms of how various turbulent fluid
dynamics parameters influence the response of the turbine (loads,
fatigue, etc.)
Let the turbine tell us what it does not like!
Develop the ability to include these important characteristics in
numerical inflow simulations used as inputs to the turbine design
codes
Adjust the turbulent inflow simulation to reflect site-specific
characteristics or at least general site characteristics; i.e.,
complex vs homogeneous terrain, mountainous vs Great Plains,
etc.
18. Innovation for Our Energy Future
Data Sources
18
We have had two source of measurements of both
the detailed characteristics of the turbulent inflow
and the resulting dynamic response of a wind
turbine
• Deep within a 41-row wind farm in San Gorgonio Pass,
California that contained nearly 1000 turbines in 1989-90
• The National Wind Technology Center Test Site south of
Boulder, Colorado in 1999-2000
19. Innovation for Our Energy Future19
San Gorgonio Pass California
• Large, 41-row wind farm located downwind of the
San Gorgonio Pass near Palm Springs
• Wind farm had good production on the upwind
(west) side and along the boundaries but
degraded steadily with each increasing row
downstream as the cost of turbine maintenance
increased
• Frequent turbine faults occurred during period
from near local sunset to midnight
• Significant amount of damage to turbine
components including blades and yaw drives
20. Innovation for Our Energy Future
San Gorgonio Regional Terrain
20
Pacific Ocean
Salton
Sea
wind farms
(152 m, 500 ft)
(−65 m, −220 ft)
(793 m, 2600 ft)
Los Angeles
Basin
Mohave Desert
Sonoran
Desert
San Bernardino Mountains
21. Innovation for Our Energy Future
Wind Farm Nearby Topography
21
Palm Springs
Mt. Jacinto
(
downwind
tower
(76 m, 200 ft)
upwind
tower
(107 m, 250 ft)
row 37
San Gorgonio Pass
nocturnal
canyon flow
(3166 m, 10834 ft)
22. Innovation for Our Energy Future
Side-by-Side Turbine Testing
at Row 37
7D row-to-row spacing
Gathering Data in a Wind Farm Environment
SeaWest 41-row San Gorgonio Wind Farm in 1989 & 1990 – A legacy site
23. Innovation for Our Energy Future
Analyzing San Gorgonio Wind Farm Turbine
Turbulence-Turbine Responses
23
• Two, 65 kW side-by-side turbines were available that were
identical except for different rotor aerodynamic designs
• Location was deep within the wind farm with turbines 7
rotor diameters upstream
• Very turbulent wake conditions produced elevated turbine
dynamic responses that allowed better correlation with
turbulent scaling parameters
• Provided initial analyses of turbulence-turbine
interactions that could be extended and refined using data
from the NWTC experiment
24. Innovation for Our Energy Future
December 1999 to May 2000
24
Testing at the NWTC
25. Innovation for Our Energy Future
Gathering Response Data in the Natural Flow of a High
Turbulence Site
25
NWTC
(1841 m – 6040 ft)
NWTC
Great Plains
Terrain Profile Near NWTC in Direction of Prevailing Wind
ection
Denver
Boulder
•Strong downslope
winds (Chinooks)
from the 13,000
foot Front Range
Mountains that
occur during the
fall, winter, and
spring months
•The winds have a
distinct pulsating
characteristic that
contain strong,
turbulent bursts
26. Innovation for Our Energy Future
Measurements at the NWTC
26
• Measurements were made with the naturally-
occurring wind flows, no upstream turbine wakes
• Data was taken in flows that originated over the
Front Range of the Rocky Mountains to the West
• Objective was to compare the turbine response to
natural turbulent flows with those measured in the
multi-row wind farm
27. Innovation for Our Energy Future
3-axis sonic anemometers/thermometers
Details of Inflow Turbulence
Dynamics Measured By
Planar Array of Sonic
Anemometers
Measured the Resulting
Dynamic Responses
of the ART Turbine
Using An Upwind Inflow Array and a 600 kW Turbine
80-m mean wind speed, V80 (m/s)
80-mturbulence
intensity,I80
rated wind
speed range
The NWTC is a Very Turbulent Site!
Turbulence intensity Standard deviation
Nov 1999-April 2000
28. Innovation for Our Energy Future28
What We Have Found From Testing at Both
Sites
• In a wake environment deep
within a very large wind farm
• In very energetic natural
turbulent flow downwind of a
major mountain range
29. Innovation for Our Energy Future
Turbulence and Wind Turbines
29
• Turbulence in the turbine inflow has a significant
influence on the power performance efficiency and
the lifetime of turbine components
• The primary source of degraded performance and
component reliability are the unsteady aerodynamic
effects created by turbulent flow over the turbine
rotor blades
• These unsteady effects create dynamic loads on the
rotor blades that in turn excite a range of vibrational
frequencies associated with the turbine structure that
must be dissipated by the turbine structure
30. Innovation for Our Energy Future
Turbulence-Induced Dynamic Loads
30
• The fluctuating structural loads created by turbulent
flow across the turbine rotor blades are one of the
most important sources of cyclic stresses in the
mechanical components of the turbine
• These cyclic stresses cumulatively induce
component fatigue damage that continues to
increase until failure
• We will now look at what we have found in our
research that relates turbulent flow properties to
fatigue damage accumulation.
31. Innovation for Our Energy Future
Alternating stress cycles/hour
Source: Jackson, K. L., July 1992, “Estimation of Fatigue Life Using Field Test Data,”
Oral presentation to the NREL Wind Energy Program Subcontractor Review Meeting,
Golden, CO.
An Example of the Relationship Between Applied Cyclic
Stresses and Cumulative Fatigue Damage
High Fatigue
Damage
Turbine Steel Low-Speed Shaft
Predictedalternatingstress(kNm)
Stress amplitude versus
frequency of occurrence
Predictedcumulativedamage(%)
Cumulative Fatigue Damage
A few large stress cycles
are more damaging than many
smaller ones!
32. Innovation for Our Energy Future
Load Cycle Frequency Distributions
32
In analyzing turbulence-induced alternating stress or
load cycles in wind turbines we found:
• Small amplitude, often occurring load cycles
were normally or Gaussian distributed
• Less frequent and more damaging high
amplitude cycles were exponentially
distributed
33. Innovation for Our Energy Future
N
cycles
per
hour
Characteristic alternating load cycle magnitude, Mp-p
Fewer cycles
but more intense:
Exponentially
Distributed
More cycles
but lower
intensity:
Gaussian
distributed
High Fatigue Damage
Region
Observed Blade Root Loading Cycle Distributions
What does this say about the nature
of the turbulence excitation?
34. Innovation for Our Energy Future
Example of Distribution of Alternating Blade Root Out-
of-Plane Loading Cycles From An Actual Turbine Blade
34
OBSERVED RAINFLOW SPECTRA FOR AWT-26/P2 TURBINE
(Tehachapi Pass, California)
P-P root flapwise bending moment, kNm
0 25 50 75 100 125
Cycles/hr
10-1
100
101
102
103
104
exponential fit
Observed Turbulent Load Cycle Spectra for
AWT-26/P2 Turbine
(Tehachapi Pass, California)
35. Innovation for Our Energy Future
N
cycles
per
hour
increased
fatigue
damage
decreased
fatigue
damage
Characteristic alternating load cycle magnitude, Mp-p
Slope of Loading Distribution Determines Level of
Fatigue Damage
36. Innovation for Our Energy Future
Turbine Response
Dynamic Load
Statistical
Distribution
Model
Dominant Inflow
Turbulence Scaling
Parameter(s)
Percent
Variance
Explained#
Blade root out-of-plane bending Exponential , Ri 89
Low-speed shaft torque Exponential , Ri 78
Low-speed shaft bending Exponential , Ri 94
Yaw drive torque Exponential , Ri 87
Tower top torque Exponential , 88
Tower axial bending Exponential σH 78
Nacelle inplane thrust Exponential , Ri 77
Tower inplane thrust Exponential 69
Blade root inplane bending Extreme value 86
1/2
(| ' '|)u w
1/2
(| ' '|)u w
1/2
(| ' '|)u w
1/2
(| ' '|)u w
1/2
(| ' '|)u w
1/2
(| ' '|)u w
HU
1/2 1/2 1/2
(| ' '|) ,(| ' '|) ,(| ' '|)u w u v v w
1/2 1/2
(| ' '|) , (| ' '|)u w v w
#includes both turbines, values greater for turbine equipped with NREL blades
Multivariate ANOVA Analysis Results of San Gorgonio Wind Farm
Turbine Response Variables and Turbulence Scaling Parameters
37. Innovation for Our Energy Future
N
cycles
per
hour
Characteristic alternating load cycle magnitude, Mp-p
N = βoe−β
1
M
p-p
Rotor Blade Root Out-of-Plane Larger Amplitude Loads
Scale with Turbine Layer Dynamic Stability and Hub u*
β1 = f(Ri, u*hub)
38. Innovation for Our Energy Future
Hub local shear stress, u* (m/s)
1 1
2 2
exp exp 1p p
o
M M
N
γ γ
γ
γ γ
−
− −
= − − − +
Rotor Blade Root In-Plane High Amplitude Loads Scale
with Turbine Layer Dynamic Stability and Hub u*
• Blade root in-plane (edgewise) cyclic load distributions have two peaks:
• a lower amplitude one due to the once/revolution gravity load
• a higher amplitude one due to turbulence
• Gumbel Extreme Value Distribution Describes High Blade Root In-Plane Loads
39. Innovation for Our Energy Future
Gradient Richardson number, Ri
Blade Root Out-of-Plane Load Cycle Exponential
Distribution Slope Parameter β1 vs Turbine Layer Stability
INFLOW TURBULENCE
SCALING VARIABLES
TURBINE
DYNAMIC
RESPONSE
VARIABLE
M-O Stability Parameter, z/L
40. Innovation for Our Energy Future
Gradient Richardson number, Ri
Blade Root In-Plane (Edgewise) Load Cycle Extreme Value
Distribution Shape Parameter γ2 vs Turbine Layer Dynamic
Stability
41. Innovation for Our Energy Future
Gradient Richardson number, Ri
Normalizedcrosscovariance(uiuj)/ij
Peakbladerootflapbendingmoment(kNm)
Turbulence Vertical Component is a Key Player in Turbine
Dynamic Response
Large peak loads
tend to be associated
with the vertical wind
component
42. Innovation for Our Energy Future
Micon 65 Turbine Root Flap Moment Fatigue Damage Loads
as a Function of Hub Local u* and Turbine Layer Ri
6
8
10
12
14
16
18
20
22
24
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
-0.4
-0.3
-0.2
-0.1
0.0
0.1
Damageequivalentload(kNm)
Hub local u*
value (m/s)
Turbine layer Ri
6
8
10
12
14
16
18
20
22
24
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
-0.4
-0.3
-0.2
-0.1
0.0
0.1
Damageequivalentload(kNm)
Hub local u *
value (m
/s)
Turbine layer Ri
6
8
10
12
14
16
18
20
22
24
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
-0.4
-0.3
-0.2
-0.1
0.0
0.1
Damageequivalentload(kNm)
Hub local u *
value (m/s)
Turbine layer Ri
6
8
10
12
14
16
18
20
22
24
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
-0.4
-0.3
-0.2
-0.1
0.0
0.1
Damageequivalentload(kNm)
Hub local u *
value (m
/s)
Turbine layer Ri
Peak Value from
Three Blades
Three Blade
Average Value
AeroStar Rotor NREL Rotor
Unstable
Stable
43. Innovation for Our Energy Future43
What are the details of the turbulent wind
field and turbine blade to produce these
responses?
44. Innovation for Our Energy Future
NREL blade
Turbine Blade Response Due to Turbulence-Induced
Unsteady Aerodynamic Response Stress Cycles!
Organized or Coherent Turbulence is a Major
Contributor to Turbine Fatigue Damage
Inflow turbulence characteristics
Coherent turbulent structures
Turbine Dynamic Responses
45. Innovation for Our Energy Future
Turbulent Structures That Induce Turbine Dynamic
Responses Can be Smaller than the Rotor Disk
Their Intensity is a Function of the Dynamic Stability of
the Rotor Layer
Ri =+0.034
more intense peak
loads generated
within single blade
rotation
Ri = +0.007
blades encountered
turbulent structures at
the same location
during three consecutive
rotor rotations
Peak Blade Root Out-of-Plane Bending Loads Generated within Rotor Rotations
46. Innovation for Our Energy Future
Here we compare results from both the San Gorgonio Wind
Farm and the NWTC Measurements to see if there are any
systematic differences
46
Are There Certain Times of Day and BL
Conditions when Greater Fatigue Damage
Occurs?
47. Innovation for Our Energy Future
Diurnal Variations in High Blade Structural Loads
San Gorgonio Wind Farm Micon 65 Turbines at Row 37
Time-of-Day Distribution of Occurences of High Blade Loads
Local standard time (h)
2 4 6 8 10 12 14 16 18 20 22 24
Probability(%)
0
2
4
6
8
10
12
14
sunrise sunrset
Local standard time (h)
0 2 4 6 8 10 12 14 16 18 20 22 24
Probability(%)
0
2
4
6
8
OctMay Oct May
NWTC ART Turbine
Time-of-Day Distribution of Occurences of High Blade Loads
too
turbulent
for
turbine to
operate
winds below
turbine
cut-in
wind speed
Peak Blade Loads
Occur At Same Point
In Diurnal Cycle
48. Innovation for Our Energy Future
Mean Wind Speeds Associated With High Fatigue Loads
Distributions of Hub-height Mean Wind Speeds Associated with
High Values (P95) of Rotor Blade Root Fatigue Loads
Hub mean wind speed (m/s)
8 10 12 14 16 18
Probability(%)
0
10
20
30
40
rated wind speed
San Gorgonio Micon 65 Turbine
Hub mean wind speed (m/s)
8 10 12 14 16 18
Probability(%)
0
5
10
15
20
25
30
rated wind speed
NWTC ART Turbine
Conclusion: Highest Blade Root Fatigue Damage Occurs Near Rated Wind Speed!
49. Innovation for Our Energy Future
-0.06 -0.04 -0.02 0.00 0.02 0.04 0.06 0.08 0.10
Probability(%)
0
10
20
30
40
50
60
-0.08 -0.06 -0.04 -0.02 0.00 0.02 0.04
Probability(%)
0
5
10
15
20
25
unstable
conditions
stable
conditions
stable
conditions
unstable
conditions
Ri
Atmospheric Stability Probability Associated with High
Levels (P95) of Turbine Blade Loading
San Gorgonio Micon 65 kW Turbine NWTC ART 600 kW Turbine
• Highest fatigue loading occurs in weakly stable flow conditions
• Much greater probability of encountering high loading at Row 37 in the
California wind farm likely due to influence of upstream turbine wakes
50. Innovation for Our Energy Future
NWTC Diurnal Variation of Turbine Layer Stability
Diurnal Variation of Turbine Layer Ri During Turbine Operation
Local standard time (h)
0 2 4 6 8 10 12 14 16 18 20 22 24
Ri
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
Ric
critical upper limit
significant turbine response upper limit
P05-P95
Ri = +0.1
Ri = +0.05
Significant probability of stability in critical range!
51. Innovation for Our Energy Future51
Need a Way to Correlate Organized Turbulent
Structures and Turbine Component Fatigue
• Need single numbers that represent
– Level of turbine component fatigue damage
– Intensity of turbulent energy associated with coherent structures
• Damage Equivalent Load (DEL)
– a measure of the equivalent fatigue damage caused by each load taking into
account the fatigue properties of the material
where DEL = (Σ Ni Li
m / Neq )1/m
where Ni is the number of cycles for load Li , m is dependent on the material
(steel = 3 and composite = 10 is usually used), and
Neq is the equivalent number of cycles within a 10-minute period (at a 1 Hz
reference frequency it is 1200)
– It describes the level of fatigue damage with one number
• Coherent TKE (CTKE or Coh TKE)
– Defined as the partition of turbulent kinetic energy that is coherent as
CTKE = 1/2[ (u’w’)2 + (u’v’)2 + (v’w’)2]1/2; CTKE of isotropic turbulence = 0
52. Innovation for Our Energy Future
Conclusions from Measurements from San Gorgonio
Pass Wind Farm and at the NWTC
52
Similar load sensitivities to vertical
stability (Ri) and vertical wind motions
were found at both locations
We found that the turbine loads were
also responsive to the new inflow
scaling parameter, Coherent Turbulent
Kinetic Energy (CTKE) with greater
levels of fatigue damage occurring
with high values of this variable
In both locations, the peak damage
equivalent load occurred at a slightly
stable value of Ri in the vicinity of
+0.02
Clearly, based on both sets of
measurements, coherent or organized
turbulence played a major role in
causing increased fatigue damage on
wind turbine rotors
San Gorgonio
Micon 65/13
NWTC 600 kW ART
53. Innovation for Our Energy Future
Overall Interpretation of the Field Measurements
53
The greatest fatigue damage occurs during the nighttime hours when
the atmospheric boundary layer up to the maximum height of the
turbine rotor is just slightly stable (0 < Ri < +0.05)
Significant vertical wind shear was often also present
Both of these conditions are prerequisites for Kelvin-Helmholtz
Instability (KHI)
The presence of KHI can be responsible for generating atmospheric
motions called KH billows or waves which in turn generate coherent
turbulence as they breakdown or decay
54. Innovation for Our Energy Future
Let’s look at these details but first we need to discuss a
analytical tool that is necessary to for us to identify the
mechanisms involved
54
How does turbulent energy in the turbine
inflow contribute to the fatigue damage of
structural components?
55. Innovation for Our Energy Future
Power
Spectrum
55
Conventional Power Spectrum of Blade Flapwise
Load Time History
Frequency (Hz)
0.1 1 10
Rootflapload(kNm)2
/Hz
10-5
10-4
10-3
10-2
10-1
100
101
102
103
1-P
Zero-mean flapwise loads
Time (s)
0 10 20 30 40 50 60
kNm
-15
-10
-5
0
5
10
15
20
Time Series Representation
•Excellent frequency
resolution or localization
(0.1 Hz)
•Very poor time resolution
or localization (60 secs)
Frequency Domain Representation
Power
Spectrum
But what is
the spectral
distribution for
these transient
event peaks?
56. Innovation for Our Energy Future56
Use of Continuous Wavelet Transform to Examine Stress Energy
Distribution of Turbulence-Induced Transient Loads
Wind Turbine Blade Root Out-of-Plane Time-Varying Load
data sample number (time)
min - dynamic stress energy - max
1-P (0.93 Hz)
0.4
0.5
0.7
0.6
0.8
1.0
1.2
1.5
3.0
5.0
10.0
2.0
Scales
Wavelet Scalogram
57. Innovation for Our Energy Future
Time Series and Wavelet Analyses Presentations
Time
Histories
Continuous Wavelet Transform
Coefficients of
Root Flapwise-Bending Signal
Discrete Wavelet Transform
Detail Frequency Bands of
Root Flapwise-Bending Signal
(Multi-resolution Analysis)
Time
Hub-height horizontal wind speed
Hub-height Reynolds stresses
Root flapwise-bending load
59. Innovation for Our Energy Future
Upwind array
inflow CTKE
m
2
/s
2
0
20
40
60
80
100
120
0
20
40
60
80
100
120
rotor top (58m)
rotor hub (37m)
rotor left (37m)
rotor right (37m)
rotor bottom (15m)
IMU velocity components
0 2 4 6 8 10 12
mm/s
-20
-10
0
10
20
-20
-10
0
10
20
Time (s)
492 494 496 498 500 502 504
vertical (Z)
side-to-side (Y)
fore-aft (X)
zero-mean
root flap
bending
moment
kNm
-400
-300
-200
-100
0
100
200
300
400
-400
-300
-200
-100
0
100
200
300
400
Blade 1
Blade 2
Response to Intense Coherent Inflow Event on ART
Turbine
59
Intense coherent structure
encountered at center of
rotor disk (80 m2/s2)
Significant blade root out-of-plane
bending excursions (~ 500 kNm)
response
Upwind Planar Array
Sonic Measurements
Out-of-Plane
Blade Root
Loads
High frequency resonant response
in lateral and vertical directions
of low-speed shaft forward
support bearing
Orthogonal Velocity
Measurements at Head
of Low-Speed Shaft
60. Innovation for Our Energy Future
400 450 500 550 600
-1000
0
1000
(m/s)3
400 450 500 550 600
-1000
0
1000
(m/s)3
400 450 500 550 600
-1000
0
1000
(m/s)3
Time (seconds)
58 m
37 m
15 m
TKE Vertical Flux During This Coherent Event
58-m level (rotor top)
37-m level (hub)
15-m level (rotor bottom)
VerticalTKEflux(m/s)3
Time (seconds)
environment
more stable
(increased turbulence damping)
environment
less stable
available
turbulent
kinetic
energy
turbulence generation
Downward Transport of Turbulent Kinetic Energy
61. Innovation for Our Energy Future
Corresponding Day and Night Example Flapwise
Load Cycle Counting Spectra
0 100 200 300 400 500 600
10
-4
10
-3
10
-2
10
-1
10
0
10
1
Peak-to-peak Amplitude (kNm)
Cycles/second
Nocturnal Boundary Layer
Daytime Boundary Layer
560 kNm cycle
Peak-to-peak load amplitude (kNm)
560 kNm cycle
Cycles/second
result of
rotor
encountering
coherent
event
produces a
“rare event”
62. Innovation for Our Energy Future62
Let’s Use a Version of the Wavelet Analysis
Tool to See What the Impact of
Encountering A Coherent Turbulent
Structure Has on the Turbine Drive train
63. Innovation for Our Energy Future
ART Turbine Rotor/Drive Train Time Series Parameters
Associated with Intense Coherent Event
Blade 1 root zero-mean inplane bending load
Bearing Fore-aft
velocity
Bearing Side-Side
velocity
Bearing Vertical
velocity
Low-Speed Shaft
torque
Low-Speed Shaft Forward Support Bearing
Time Series Data
Measured by an Inertial Measurement Unit (IMU)
Mounted on Top of Bearing and Aligned with Low-Speed Shaft
64. Innovation for Our Energy Future
Turbulence-induced KE Flux from ART Rotor into Low-
Speed Shaft Associated with Coherent Event – cont’d
64
Blade in-plane response
Bearing response
KE flux into bearing
Co-Scalograms
Scalograms
Scalograms
65. Innovation for Our Energy Future
Conclusion
65
• The encountering of a coherent turbulent structure
simultaneously excites many vibrational (modal)
frequencies in the turbine blade as it passes through it
• The KE energy associated with each frequency sums
coherently creating a highly energetic burst
• This burst is applied to the structure as an impulse
which can be more damaging than cyclic loading
because of the energy density is greater
• Thus conditions that produce coherent turbulent
structures such as KH instability can be hard on wind
turbine structures and decrease component life if
frequently encountered
66. Innovation for Our Energy Future
The Stable BL Is Hard on Wind Turbines
• Buoyancy plays a major role in shaping the impact of
coherent turbulent structures in the stable BL and the
subsequent impact on wind turbine components
• KH instability is a major player in the generation of coherent
turbulent structures in the nocturnal BL when much of the
fatigue damage to wind turbine structural components takes
place
Height
Time
wind
turbines
Coherent turbulent structures observed in stable BL by NOAA/ESRL HRDL Lidar in Southeast Colorado
during NREL/NOAA Lamar Low-Level Jet Project, September 2003.
Coherent
Structures
67. Innovation for Our Energy Future
Buoyancy Damping Is A Major Player . . .
67
PeakFlapwiseStressCycle(kNm)
0
100
200
300
400
500
600
TurblinelayerRi
0.001
0.01
0.1
1
TL Ri vs TL Lb/D
Turbine layer lb/D
0.1 1 10
HubPeakCTKE(m2
/s2
)
1
10
100
Turbine layer Ri
0.0001 0.001 0.01 0.1 1
TurbineLayerlb/D
0.1
1
10
Buoyancy Damping
Limits Coherent Structure
Size & Intensity and
Reduces Induced Stress
Cycle Magnitude
lb= buoyancy length scale,
D = rotor diameter
/b w BVl Nσ=
Length Scale = Rotor Disk Diameter
Cyclic stress level
Turblne Layer Stability
Hub-level CTKE
moderate
buoyancy
damping
high
buoyancy
damping
low
buoyancy
damping
68. Innovation for Our Energy Future
Turbine layer Ri
0.0001 0.001 0.01 0.1 1
TurbineLayerlb/D
0.1
1
10
The Damping Present Influences the Nature of the
Transient Loads Seen on Wind Turbines
high
buoyancy
damping
Ri =+0.034Ri = +0.007
low
buoyancy
damping
moderate
buoyancy
damping
Upwind array
inflow CTKE
m
2
/s
2
0
20
40
60
80
100
120
0
20
40
60
80
100
120
rotor top (58m)
rotor hub (37m)
rotor left (37m)
rotor right (37m)
rotor bottom (15m)
IMU velocity components
0 2 4 6 8 10 12
mm/s
-20
-10
0
10
20
-20
-10
0
10
20
Time (s)
492 494 496 498 500 502 504
vertical (Z)
side-to-side (Y)
fore-aft (X)
zero-mean
root flap
bending
moment
kNm
-400
-300
-200
-100
0
100
200
300
400
-400
-300
-200
-100
0
100
200
300
400
Blade 1
Blade 2
Ri = +0.015
69. Innovation for Our Energy Future
Conclusions
69
• Spatiotemporal turbulent structures exhibit strong transient
features which in turn induce complex transient loads in wind
turbine structures
• The encountering of patches of coherent turbulence by wind
turbine blades can cause amplification of high frequency
structural modes and perhaps increased local dynamic stresses
in turbine components that are not being adequately modeled
with the inflow simulations used by turbine designers
• Current wind turbine engineering design practice employs
turbulence inflow simulations that are based on neutral,
homogeneous flows that do not reflect the diabatic
heterogeneity that is particularly present in the SBL as we
discussed today
• We believe this disconnect is a major contributor to the
observed wind farm production underperformance and
cumulative maintenance and repair costs
70. Innovation for Our Energy Future
Conclusions – cont’d
70
• Physics-based CFD simulations have the capability of
providing accurate and realistic inflows but 1000s of
simulations are often needed in the turbine design process
and their computational cost makes them feasible for only
a small class of specific problems
• Purely Fourier-based stochastic inflow simulation
techniques cannot adequately reproduce the transient,
spatiotemporal velocity field associated with coherent
turbulent structures
• The NREL TurbSim stochastic inflow simulator has been
designed to provide such a capability for both general and
site specific environments
71. Innovation for Our Energy Future
For more information. . .
71
• Kelley, N. D., 1993, “The identification of inflow fluid dynamics parameters that can
be used to scale fatigue loading spectra of wind turbine structural components,”
NREL/TP-442-6008
• Kelley, N. D., 1994, “Turbulence descriptors for scaling fatigue loading spectra of
wind turbine structural components,” NREL/TP-442-7035
• Kelley, N. D., 1999, “A case for including atmospheric thermodynamic variables in
wind turbine fatigue loading parameter identification,” NREL/CP-500-26829.
• Kelley, N. D., Osgood, R. M., Bialasiewicz, J. T., and Jakubowski, A., 2000, “Using
wavelet analysis to assess turbulence-rotor interactions,” Wind Energy, 3(3), 121-
134.
• Kelley, N., Hand, M., Larwood, S., and McKenna, E.,2002, “The NREL Large-Scale
Turbine Inflow and Response Experiment – Preliminary Results,” NREL/CP-500-
30917
• Kelley, N. D., Jonkman, B. J., and Scott, G. N., 2005, “The impact of coherent
turbulence on wind turbine aeroelastic response and its simulation,” NREL/CP-500-
38074.
• Kelley, N. D., Jonkman, B. J., 2007, “Overview of the TurbSim Stochastic Inflow
Turbulence Simulator Version 1.21,” NREL/TP-500-41137.
72. Innovation for Our Energy Future
A Discussion Question . . .
72
Given a familiarity of the information presented in
this lecture . . .
How would a boundary layer meteorologist
develop a systematic approach to assessing the
turbulence operating environment of candidate
wind energy resource sites in order to insure
compatibility with both the turbine designs being
proposed and the operational protocol?
How can this be communicated to the developer,
turbine supplier, and wind farm operator?