Calculating Power
To calculate the amount of power a turbine can actually generate from the wind, you need to know the wind speed at the turbine site and the turbine power rating. Most large turbines produce their maximum power at wind speeds around 15 meters per second (33 mph). Considering steady wind speeds, it's the diameter of the rotor that determines how much energy a turbine can generate. Keep in mind that as a rotor diameter increases, the height of the tower increases as well, which means more access to faster winds. Read more...
Thursday, September 24, 2009
Wednesday, September 23, 2009
How Wind Turbines Work
Public Library article: http://www1.eere.energy.gov/windandhydro/wind_how.html
Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetation. Humans use this wind flow, or motion energy, for many purposes: sailing, flying a kite, and even generating electricity.
The terms wind energy or wind power describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity.
So how do wind turbines make electricity? Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. Take a look inside a wind turbine to see the various parts. View the wind turbine animation to see how a wind turbine works.
This aerial view of a wind power plant shows how a group of wind turbines can make electricity for the utility grid. The electricity is sent through transmission and distribution lines to homes, businesses, schools, and so on.
Anemometer: Measures the wind speed and transmits wind speed data to the controller.
Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
Brake: A disc brake, which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 55 mph. Turbines do not operate at wind speeds above about 55 mph because they might be damaged by the high winds.
Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1000 to 1800 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.
Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-speed shaft: Drives the generator.
Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Nacelle: The nacelle sits atop the tower and contains the gear box, low- and high-speed shafts, generator, controller, and brake. Some nacelles are large enough for a helicopter to land on.
Pitch: Blades are turned, or pitched, out of the wind to control the rotor speed and keep the rotor from turning in winds that are too high or too low to produce electricity.
Rotor: The blades and the hub together are called the rotor.
Tower: Towers are made from tubular steel (shown here), concrete, or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind," facing away from the wind.
Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Yaw motor: Powers the yaw drive.
Public Library article: http://www1.eere.energy.gov/windandhydro/wind_how.html
Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetation. Humans use this wind flow, or motion energy, for many purposes: sailing, flying a kite, and even generating electricity.
The terms wind energy or wind power describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity.
So how do wind turbines make electricity? Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. Take a look inside a wind turbine to see the various parts. View the wind turbine animation to see how a wind turbine works.
This aerial view of a wind power plant shows how a group of wind turbines can make electricity for the utility grid. The electricity is sent through transmission and distribution lines to homes, businesses, schools, and so on.
Inside the Wind Turbine
Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate.
Brake: A disc brake, which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies.
Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 55 mph. Turbines do not operate at wind speeds above about 55 mph because they might be damaged by the high winds.
Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1000 to 1800 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes.
Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.
High-speed shaft: Drives the generator.
Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute.
Nacelle: The nacelle sits atop the tower and contains the gear box, low- and high-speed shafts, generator, controller, and brake. Some nacelles are large enough for a helicopter to land on.
Pitch: Blades are turned, or pitched, out of the wind to control the rotor speed and keep the rotor from turning in winds that are too high or too low to produce electricity.
Rotor: The blades and the hub together are called the rotor.
Tower: Towers are made from tubular steel (shown here), concrete, or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind," facing away from the wind.
Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind.
Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind.
Yaw motor: Powers the yaw drive.
Public Library article: http://www1.eere.energy.gov/windandhydro/wind_how.html
Wind Generator Books & Plans
Wind Energy Basics: A Guide to Small and Micro Wind Systems
The wind power industry has been transformed by dramatic breakthroughs in efficiency, economy, and adaptability.
Wind Energy Basics is information about small wind systems. The book includes the unique "standard small wind turbine rating" developed by the author, which is designed to help readers wade through conflicting performance claims by manufacturers in the U.S. and overseas. Also included is detailed information on planning, siting, and installing a wind system, and on integrating wind power with solar for more cost-effective and reliable off-the-grid applications.
In addition, Gipe provides a discussion of "net metering" and intertie possibilities, explaining how homeowners in many states can now sell their excess electricity back to the utility company.
Wind Energy Basics is an excellent introduction to wind power for educational programs concerned with state-of-the-art renewable energy options, and will be indispensable for those considering today's generation of quiet, efficient, and reliable "micro" wind turbines.
Wind Energy Basics describes a new class of small wind turbines, dubbed micro turbines, which are so small that they can be purchased for less than $1000 and carried in your hands.
The debut of micro wind turbines brings the technology within reach of almost everyone. These inexpensive machines, when coupled with readily available photovoltaic panels (solar cells), have revolutionized living in remote homes off-the-utility grid. And the increasing popularity of micro wind turbines has opened up new applications previously considered off-limits to wind energy, such as charging electric fences and powering remote telephone call boxes, once the sole domain of solar cells.
Micro wind turbines have been around for decades for use on sailboats, but they have gained increasing prominence in the 1990s as their broader potential for off-the-grid applications on land has become more widely known. While micro wind turbines have yet to reach the status of widely available consumer commodities such as personal computers, the day may not be far off. The use of wind power is "exploding," say Karen and Richard Perez in their foreword. "There are currently over 150,000 small-scale RE (renewable energy) systems in America and they are growing by 30% yearly. The small-scale use of wind power is growing at twice that amount--over 60% per year," according to the Perezes, the editors of Home Power magazine.
"What Americans, and folks all over the world, are finding out," the Perezes say, "is that wind power is an excellent and cost-effective alternative" to extending electric utility lines, and fossil-fueled backup generators.
Wind Energy Basics explains how it is possible—in some states—for homeowners to run their kilowatt-hour meter backwards with a small wind turbine.
This book confronts the common but controversial practice of "power rating" that may mislead consumers about the potential of some small wind turbines. Known for his frank style, Gipe quickly cuts through technological jargon and the hype surrounding power ratings.
"Nothing tells you more about a wind turbine's potential than rotor diameter—nothing. The wind turbine with the bigger rotor will almost invariably generate more electricity than a turbine with a smaller rotor, regardless of their generator ratings," he says.
Gipe also comes down hard on roof-top mounting. "Don't bother," he warns. "It's not worth the trouble." He also minces few words on mounting wind turbines in trees. "Sometimes wind energy isn't the right choice," Gipe says. "If you live in a forest of tall trees and you can't afford a tower tall enough to clear the trees, then wind energy isn't for you."
Worldwide, wind energy is booming. Not since the heyday of the American farm windmill has wind energy grown at such a dramatic pace.
The commercial success of medium-size wind turbines, or wind farm machines, is only part of the story. Small wind turbines have found their role expanding as well. Whether it's on the contemporary homestead of Ed Wulf in California's Tehachapi Mountains, in the Chilean village of Puaucho overlooking the Pacific Ocean, or on the Scoraig peninsula of Scotland's wind-swept west coast, small wind turbines are making an important difference. While their contributions may be small in absolute terms, small wind turbines make a big difference in the daily lives of people in remote areas around the globe. Small wind turbines may produce only a few tens of kilowatt-hours per month, but this electricity goes much further and provides as much, if not more, value to those who depend upon it as does the generation of their bigger brethren.
Today there are more than 50 manufacturers of small wind turbines worldwide, and they produce more than 100 different models. Altogether manufacturers in western countries have built 100,000 small wind turbines during the last two decades. And tens of thousands more have been manufactured in China for use by nomads on the Mongolian steppes.
Wind Energy Basics is richly illustrated with photographs of small wind turbines, from those on the Patagonian steppes at the tip of South America to those on the wind-swept shores of Denmark.
The book contains information on most major small wind turbines on the international market. It also provides photographs of common wind turbine applications, including their use for wind power plants, vacation homes, third world villages, farms, water pumping, and so on.
The appendix to Wind Energy Basics includes detailed product specifications for most popular micro and mini wind turbines, as well as sources for wind pumps (farm windmills), used wind turbines, anemometers, inverters, trade associations, and mail-order catalogs that sell wind turbines.
About the Author and Books
In addition to Chelsea Green's Wind Power for Home, Farm & Business , Paul Gipe is the author of the landmark Wind Energy Comes of Age, which was selected by the American Library Association as one of the outstanding academic books of 1995. In 1998, the World Renewable Energy Conference hailed him as a "pioneer in renewable energy," awarding Gipe one of the organization's highest honors for his two decades of writing and lecturing about wind energy. Gipe lives in Bakersfield, California.
The wind power industry has been transformed by dramatic breakthroughs in efficiency, economy, and adaptability.
Wind Energy Basics is information about small wind systems. The book includes the unique "standard small wind turbine rating" developed by the author, which is designed to help readers wade through conflicting performance claims by manufacturers in the U.S. and overseas. Also included is detailed information on planning, siting, and installing a wind system, and on integrating wind power with solar for more cost-effective and reliable off-the-grid applications.
In addition, Gipe provides a discussion of "net metering" and intertie possibilities, explaining how homeowners in many states can now sell their excess electricity back to the utility company.
Wind Energy Basics is an excellent introduction to wind power for educational programs concerned with state-of-the-art renewable energy options, and will be indispensable for those considering today's generation of quiet, efficient, and reliable "micro" wind turbines.
Wind Energy Basics describes a new class of small wind turbines, dubbed micro turbines, which are so small that they can be purchased for less than $1000 and carried in your hands.
The debut of micro wind turbines brings the technology within reach of almost everyone. These inexpensive machines, when coupled with readily available photovoltaic panels (solar cells), have revolutionized living in remote homes off-the-utility grid. And the increasing popularity of micro wind turbines has opened up new applications previously considered off-limits to wind energy, such as charging electric fences and powering remote telephone call boxes, once the sole domain of solar cells.
Micro wind turbines have been around for decades for use on sailboats, but they have gained increasing prominence in the 1990s as their broader potential for off-the-grid applications on land has become more widely known. While micro wind turbines have yet to reach the status of widely available consumer commodities such as personal computers, the day may not be far off. The use of wind power is "exploding," say Karen and Richard Perez in their foreword. "There are currently over 150,000 small-scale RE (renewable energy) systems in America and they are growing by 30% yearly. The small-scale use of wind power is growing at twice that amount--over 60% per year," according to the Perezes, the editors of Home Power magazine.
"What Americans, and folks all over the world, are finding out," the Perezes say, "is that wind power is an excellent and cost-effective alternative" to extending electric utility lines, and fossil-fueled backup generators.
Wind Energy Basics explains how it is possible—in some states—for homeowners to run their kilowatt-hour meter backwards with a small wind turbine.
This book confronts the common but controversial practice of "power rating" that may mislead consumers about the potential of some small wind turbines. Known for his frank style, Gipe quickly cuts through technological jargon and the hype surrounding power ratings.
"Nothing tells you more about a wind turbine's potential than rotor diameter—nothing. The wind turbine with the bigger rotor will almost invariably generate more electricity than a turbine with a smaller rotor, regardless of their generator ratings," he says.
Gipe also comes down hard on roof-top mounting. "Don't bother," he warns. "It's not worth the trouble." He also minces few words on mounting wind turbines in trees. "Sometimes wind energy isn't the right choice," Gipe says. "If you live in a forest of tall trees and you can't afford a tower tall enough to clear the trees, then wind energy isn't for you."
Worldwide, wind energy is booming. Not since the heyday of the American farm windmill has wind energy grown at such a dramatic pace.
The commercial success of medium-size wind turbines, or wind farm machines, is only part of the story. Small wind turbines have found their role expanding as well. Whether it's on the contemporary homestead of Ed Wulf in California's Tehachapi Mountains, in the Chilean village of Puaucho overlooking the Pacific Ocean, or on the Scoraig peninsula of Scotland's wind-swept west coast, small wind turbines are making an important difference. While their contributions may be small in absolute terms, small wind turbines make a big difference in the daily lives of people in remote areas around the globe. Small wind turbines may produce only a few tens of kilowatt-hours per month, but this electricity goes much further and provides as much, if not more, value to those who depend upon it as does the generation of their bigger brethren.
Today there are more than 50 manufacturers of small wind turbines worldwide, and they produce more than 100 different models. Altogether manufacturers in western countries have built 100,000 small wind turbines during the last two decades. And tens of thousands more have been manufactured in China for use by nomads on the Mongolian steppes.
Wind Energy Basics is richly illustrated with photographs of small wind turbines, from those on the Patagonian steppes at the tip of South America to those on the wind-swept shores of Denmark.
The book contains information on most major small wind turbines on the international market. It also provides photographs of common wind turbine applications, including their use for wind power plants, vacation homes, third world villages, farms, water pumping, and so on.
The appendix to Wind Energy Basics includes detailed product specifications for most popular micro and mini wind turbines, as well as sources for wind pumps (farm windmills), used wind turbines, anemometers, inverters, trade associations, and mail-order catalogs that sell wind turbines.
About the Author and Books
In addition to Chelsea Green's Wind Power for Home, Farm & Business , Paul Gipe is the author of the landmark Wind Energy Comes of Age, which was selected by the American Library Association as one of the outstanding academic books of 1995. In 1998, the World Renewable Energy Conference hailed him as a "pioneer in renewable energy," awarding Gipe one of the organization's highest honors for his two decades of writing and lecturing about wind energy. Gipe lives in Bakersfield, California.
More Equipment and Available Categories
Cat# Category Name
60 AGM Sealed Batteries
90 AlNiCo Magnets
6 Ceramic Bar Magnets & Blocks
34 Ceramic Disc Magnets & Cylinders
2 Ceramic Magnets
74 Charge Controllers & Rectifiers
17 Continuous Magnetic Roll Strips
123 Epoxy Coated Neodymium Iron Boron Magnets
20 Essex Magnet Wire
36 Ferrofluid - Magnetic Fluids
4 Flexible Magnets
102 Fronius Inverters
69 Gel Sealed Batteries
51 Industrial Magnetic Lifters
45 Industrial Magnets
48 Inkjet Printable Magnet Paper
54 Magnet Pole Detector - Identifier
9 Magnet Wire & Magnet Wire Spools
40 Magnet Wire for Generators
37 Magnetic Field Viewer Film
55 Magnetic Hooks & Clips
129 Magnetic Levitation Science Projects
25 Magnetic Pickup Tools
31 Magnetic Push Pins & Buttons
70 Magnetic Sheet Rolls w/Adhesive
18 Magnetic Sheet Rolls w/PVC
94 Magnetic Sweepers
24 Magnetic Tools-Films-Fluids & Gadgets
42 Magnetic Water Treatment
87 Modified Sine Wave Inverters
122 N50-N52 Strongest Rare Earth Magnets
15 Neodymium Arc & Wedge Rare Earth Magnets
5 Neodymium Block/Cube & Bar Magnets
11 Neodymium Disc & Cylinder Rare Earth Magnets
128 Neodymium Motorcycle Traffic Light Magnets
32 Neodymium Rare Earth Magnetic Therapy Magnets
13 Neodymium Ring & Tube Rare Earth Magnets
14 Neodymium Sphere & Ball Rare Earth Magnets
59 Perforated Magnet Strip w/PVC
16 SmCo Samarium Cobalt Block Magnets
27 SmCo Samarium Cobalt Disc Magnets
3 SmCo Samarium Cobalt Magnets
1 Strong Neodymium Magnets
28 Strontium Ferrite Ceramic Magnet Rings
60 AGM Sealed Batteries
90 AlNiCo Magnets
6 Ceramic Bar Magnets & Blocks
34 Ceramic Disc Magnets & Cylinders
2 Ceramic Magnets
74 Charge Controllers & Rectifiers
17 Continuous Magnetic Roll Strips
123 Epoxy Coated Neodymium Iron Boron Magnets
20 Essex Magnet Wire
36 Ferrofluid - Magnetic Fluids
4 Flexible Magnets
102 Fronius Inverters
69 Gel Sealed Batteries
51 Industrial Magnetic Lifters
45 Industrial Magnets
48 Inkjet Printable Magnet Paper
54 Magnet Pole Detector - Identifier
9 Magnet Wire & Magnet Wire Spools
40 Magnet Wire for Generators
37 Magnetic Field Viewer Film
55 Magnetic Hooks & Clips
129 Magnetic Levitation Science Projects
25 Magnetic Pickup Tools
31 Magnetic Push Pins & Buttons
70 Magnetic Sheet Rolls w/Adhesive
18 Magnetic Sheet Rolls w/PVC
94 Magnetic Sweepers
24 Magnetic Tools-Films-Fluids & Gadgets
42 Magnetic Water Treatment
87 Modified Sine Wave Inverters
122 N50-N52 Strongest Rare Earth Magnets
15 Neodymium Arc & Wedge Rare Earth Magnets
5 Neodymium Block/Cube & Bar Magnets
11 Neodymium Disc & Cylinder Rare Earth Magnets
128 Neodymium Motorcycle Traffic Light Magnets
32 Neodymium Rare Earth Magnetic Therapy Magnets
13 Neodymium Ring & Tube Rare Earth Magnets
14 Neodymium Sphere & Ball Rare Earth Magnets
59 Perforated Magnet Strip w/PVC
16 SmCo Samarium Cobalt Block Magnets
27 SmCo Samarium Cobalt Disc Magnets
3 SmCo Samarium Cobalt Magnets
1 Strong Neodymium Magnets
28 Strontium Ferrite Ceramic Magnet Rings
Subscribe to:
Posts (Atom)
