Wind Energy-does it really work?

[PreyingMantis]

Ok so I am new to this forum and internet stuff. However here is the link to this copied webpage. I have mixed emotions to this whole wind energy business. We need to do something but it needs to be practical and reliable to avoid fossil fuels. Give me your opinions and any other information that may help others decide if this is indeed a practial solution to energy conservation. Thank a million!

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Wind Web Tutorial

WIND ENERGY BASICS
What is wind energy? How many turbines does it take to make one megawatt (MW)?

What is a wind turbine
and how does it work? How many homes can one megawatt of wind serve?

What are wind
turbines made of? What is a wind power plant?

How big is a wind turbine? What is "capacity factor"?

How much electricity can
one wind turbine generate? If a wind turbine's capacity factor is 33%, doesn't that mean it is only running one-third of the time?

What is "availability factor"?

What is wind energy?

In reality, wind energy is a converted form of solar energy. The sun's radiation heats different parts of the earth at different rates-most notably during the day and night, but also when different surfaces (for example, water and land) absorb or reflect at different rates. This in turn causes portions of the atmosphere to warm differently. Hot air rises, reducing the atmospheric pressure at the earth's surface, and cooler air is drawn in to replace it. The result is wind.

Air has mass, and when it is in motion, it contains the energy of that motion("kinetic energy"). Some portion of that energy can converted into other forms mechanical force or electricity that we can use to perform work.

More reading:
“Where Does Wind Energy Come From”
and its subsections contain a very extensive description of the various geographical and geophysical factors that drive the circulation of the winds around our planet.

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What is a wind turbine and how does it work?

A wind energy system transforms the kinetic energy of the wind into mechanical or electrical energy that can be harnessed for practical use. Mechanical energy is most commonly used for pumping water in rural or remote locations- the "farm windmill" still seen in many rural areas of the U.S. is a mechanical wind pumper - but it can also be used for many other purposes (grinding grain, sawing, pushing a sailboat, etc.). Wind electric turbines generate electricity for homes and businesses and for sale to utilities.

There are two basic designs of wind electric turbines: vertical-axis, or "egg-beater" style, and horizontal-axis (propeller-style) machines. Horizontal-axis wind turbines are most common today, constituting nearly all of the "utility-scale" (100 kilowatts, kW, capacity and larger) turbines in the global market.



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Turbine subsystems include:

•a rotor, or blades, which convert the wind's energy into rotational shaft energy;
•a nacelle (enclosure) containing a drive train, usually including a gearbox* and a generator;
•a tower, to support the rotor and drive train; and
•electronic equipment such as controls, electrical cables, ground support equipment, and interconnection equipment.
*Some turbines do not require a gearbox

Wind turbines vary in size. This chart depicts a variety of historical turbine sizes and the amount of electricity they are each capable of generating (the turbine's capacity, or power rating).


1981 1985 1990 1996 1999 2000
Rotor (meters) 10 17 27 40 50 71
Rating (KW) 25 100 225 550 750 1,650
Annual MWh 45 220 550 1,480 2,200 5,600

The electricity generated by a utility-scale wind turbine is normally collected and fed into utility power lines, where it is mixed with electricity from other power plants and delivered to utility customers. Today (August 2005), turbines with capacities as large as 5,000 kW (5 MW) are being tested.

More reading:
Wind Energy—How Does It Work? is a fact sheet that gives additional basic information about wind energy in the U.S.

Wind Energy Technology .

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What are wind turbines made of?

The towers are mostly tubular and made of steel. The blades are made of fiberglass-reinforced polyester or wood-epoxy.

How big is a wind turbine?

Utility-scale wind turbines for land-based wind farms come in various sizes, with rotor diameters ranging from about 50 meters to about 90 meters, and with towers of roughly the same size. A 90-meter machine, definitely at the large end of the scale at this writing (2005), with a 90-meter tower would have a total height from the tower base to the tip of the rotor of approximately 135 meters (442 feet).

Offshore turbine designs now under development will have larger rotors—at the moment, the largest has a 110-meter rotor diameter—because it is easier to transport large rotor blades by ship than by land.

Small wind turbines intended for residential or small business use are much smaller. Most have rotor diameters of 8 meters or less and would be mounted on towers of 40 meters in height or less.

How much electricity can one wind turbine generate?

The ability to generate electricity is measured in watts. Watts are very small units, so the terms kilowatt (kW, 1,000 watts), megawatt (MW, 1 million watts), and gigawatt (pronounced "jig-a-watt," GW, 1 billion watts) are most commonly used to describe the capacity of generating units like wind turbines or other power plants.

Electricity production and consumption are most commonly measured in kilowatt-hours (kWh). A kilowatt-hour means one kilowatt (1,000 watts) of electricity produced or consumed for one hour. One 50-watt light bulb left on for 20 hours consumes one kilowatt-hour of electricity (50 watts x 20 hours = 1,000 watt-hours = 1 kilowatt-hour).

The output of a wind turbine depends on the turbine's size and the wind's speed through the rotor. Wind turbines being manufactured now have power ratings ranging from 250 watts to 5 megawatts (MW).

Example: A 10-kW wind turbine can generate about 10,000 kWh annually at a site with wind speeds averaging 12 miles per hour, or about enough to power a typical household. A 5-MW turbine can produce more than 15 million kWh in a year--enough to power more than 1, 400 households. The average U.S. household consumes about 10,000 kWh of electricity each year.

Example: A 250-kW turbine installed at the elementary school in Spirit Lake, Iowa, provides an average of 350,000 kWh of electricity per year, more than is necessary for the 53,000-square-foot school. Excess electricity fed into the local utility system earned the school $25,000 in its first five years of operation. The school uses electricity from the utility at times when the wind does not blow. This project has been so successful that the Spirit Lake school district has since installed a second turbine with a capacity of 750 kW. (For further information on this project, see at the Web site of the International Council for Local Environmental Initiatives.)

Wind speed is a crucial element in projecting turbine performance, and a site's wind speed is measured through wind resource assessment prior to a wind system's construction. Generally, an annual average wind speed greater than four meters per second (m/s) (9 mph) is required for small wind electric turbines (less wind is required for water-pumping operations). Utility-scale wind power plants require minimum average wind speeds of 6 m/s (13 mph).

The power available in the wind is proportional to the cube of its speed, which means that doubling the wind speed increases the available power by a factor of eight. Thus, a turbine operating at a site with an average wind speed of 12 mph could in theory generate about 33% more electricity than one at an 11-mph site, because the cube of 12 (1,768) is 33% larger than the cube of 11 (1,331). (In the real world, the turbine will not produce quite that much more electricity, but it will still generate much more than the 9% difference in wind speed.) The important thing to understand is that what seems like a small difference in wind speed can mean a large difference in available energy and in electricity produced, and therefore, a large difference in the cost of the electricity generated. Also, there is little energy to be harvested at very low wind speeds (6-mph winds contain less than one-eighth the energy of 12-mph winds).

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How many turbines does it take to make one megawatt (MW)?

Most manufacturers of utility-scale turbines offer machines in the 700-kW to 2.5-MW range. Ten 700-kW units would make a 7-MW wind plant, while 10 2.5-MW machines would make a 25-MW facility. In the future, machines of larger size will be available, although they will probably be installed offshore, where larger transportation and construction equipment can be used. Units up to 5 MW in capacity are now under development.

How many homes can one megawatt of wind energy supply?

An average U.S. household uses about 10,655 kilowatt-hours (kWh) of electricity each year. One megawatt of wind energy can generate from 2.4 to more than 3 million kWh annually. Therefore, a megawatt of wind generates about as much electricity as 225 to 300 households use. It is important to note that since the wind does not blow all of the time, it cannot be the only power source for that many households without some form of storage system. The "number of homes served" is just a convenient way to translate a quantity of electricity into a familiar term that people can understand. (Typically, storage is not needed, because wind generators are only part of the power plants on a utility system, and other fuel sources are used when the wind is not blowing. According to the U.S. Department of Energy , "When wind is added to a utility system, no new backup is required to maintain system reliability." Wind Energy Myths, Wind Powering America Fact Sheet Series, http://www.nrel.gov/docs/fy05osti/37657.pdf .)

What is a wind power plant?

The most economical application of wind electric turbines is in groups of large machines (660 kW and up), called "wind power plants" or "wind farms." For example, a 107-MW wind farm near the community of Lake Benton, Minn., consists of turbines sited far apart on farmland along windy Buffalo Ridge. The wind farm generates electricity while agricultural use continues undisturbed.

Wind plants can range in size from a few megawatts to hundreds of megawatts in capacity. Wind power plants are "modular," which means they consist of small individual modules (the turbines) and can easily be made larger or smaller as needed. Turbines can be added as electricity demand grows. Today, a 50-MW wind farm can be completed in 18 months to two years. Most of that time is needed for measuring the wind and obtaining construction permits—the wind farm itself can be built in less than six months.

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What is "capacity factor"?
Capacity factor is one element in measuring the productivity of a wind turbine or any other power production facility. It compares the plant's actual production over a given period of time with the amount of power the plant would have produced if it had run at full capacity for the same amount of time.

Actual amount of power produced over time
Capacity Factor =
Power that would have been produced if turbine
operated at maximum output 100% of the time

A conventional utility power plant uses fuel, so it will normally run much of the time unless it is idled by equipment problems or for maintenance. A capacity factor of 40% to 80% is typical for conventional plants.

A wind plant is "fueled" by the wind, which blows steadily at times and not at all at other times. Although modern utility-scale wind turbines typically operate 65% to 90% of the time, they often run at less than full capacity. Therefore, a capacity factor of 25% to 40% is common, although they may achieve higher capacity factors during windy weeks or months.

It is important to note that while capacity factor is almost entirely a matter of reliability for a fueled power plant, it is not for a wind plant—for a wind plant, it is a matter of economical turbine design. With a very large rotor and a very small generator, a wind turbine would run at full capacity whenever the wind blew and would have a 60-80% capacity factor—but it would produce very little electricity. The most electricity per dollar of investment is gained by using a larger generator and accepting the fact that the capacity factor will be lower as a result. Wind turbines are fundamentally different from fueled power plants in this respect.

If a wind turbine's capacity factor is 33%, doesn't that mean it is only running one-third of the time?

No. A wind turbine at a typical location in the Midwestern U.S. should run about 65-90% of the time. However, much of the time it will be generating at less than full capacity (see previous answer), making its capacity factor lower.

What is "availability" or "availability factor"?

Availability factor (or just "availability") is a measurement of the reliability of a wind turbine or other power plant. It refers to the percentage of time that a plant is ready to generate (that is, not out of service for maintenance or repairs). Modern wind turbines have an availability of more than 98%--higher than most other types of power plant. After more than two decades of constant engineering refinement, today's wind machines are highly reliable.

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[PreyingMantis]

THE TOP TWENTY STATES for wind energy potential, as measured
by annual energy potential in the billions of kWhs, factoring in
environmental and land use exclusions for wind class of 3 and higher.
1 North Dakota 1,210 11 Colorado 481
2 Texas 1,190 12 New Mexico 435
3 Kansas 1,070 13 Idaho 73
4 South Dakota 1,030 14 Michigan 65
5 Montana 1,020 15 New York 62
6 Nebraska 868 16 Illinois 61
7 Wyoming 747 17 California 59
8 Oklahoma 725 18 Wisconsin 58
9 Minnesota 657 19 Maine 56
10 Iowa 551 20 Missouri 52
Source: An Assessment of the Available Windy Land Area and Wind
Energy Potential in the Contiguous United States, Pacific Northwest
Laboratory, 1991.

[Glenn]

THE TOP TWENTY STATES for wind energy potential
6 Nebraska 868

I know I expend a lot of energy battling the wind in this accursed state!

[f.Channell]

In the future wind power is just one of many sources of energy which will need to be used.
They have two in the town of Hull, Massachusetts and are planning to build 4 more offshore on a shoal, funding is a problem.
Other places in Massachusetts where these could be built don't want their view disturbed.
Everyone in the town seems happy with the turbines I have talked to.
http://hullwind.org/history.php
This is a website with various info on the subject.

We shouldn't think of this as a new idea since windmills powered grain mills in New England all along the coast. Also in the early stages are methods of gaining power from tide changes.

In the case of Hull the turbine had to come from Europe. It would be good to see the USA in the future be a leader in this.

F.

[Bill Glasheen]

Wind energy - as captured by turbines - is only going to be useful in spot applications. And even with maximum use, there are issues. Expect to lose migrating birds, obstruct view, etc.

Personally I think they are cool. But I don't think the neighborhood association would go for one in my back yard. But seriously... Some solar panels on my south roof would never be noticed. That could be practical for a partial powering of a typical home.

Most of this wind and solar stuff is what you get from the brainless granola-heads who drink from the cup of Dr. Al Gore. You know... the man who invented the internet. Meanwhile if we follow the "CO2 is evil" numbnuts through an actual logical train of thought, it would lead us all to... NUCLEAR ENERGY. And boy wouldn't that be rich - having The Sierra Club and other greenies telling us that we need to forgo coal for nuclear.

It just goes to show that (real) science rules, Nature is a bitch with a sense of humor, and there must be a God after all.

- Bill

[Glenn]

Lincoln Electric here has two wind turbines as well, just on the north side of town. They are cool to watch...and a bit hypnotizing, which is not good considering they are next to an interstate. I was (unsuccessfully) looking for a good picture of them when I came across this article from last summer about a Tesla roadster cruising into Lincoln to recharge at LES wind turbine site as part of a promotion of green technologies and charities. So Bill, when you get your Tesla you can cruise the country recharging at wind turbines.

The big issue with wind turbines for many places is the effect on the landscape view, particularly in a relatively flat area where they would be most successful. Another often overlooked factor is that a lot of the areas where wind farms would be most effective do not have the transmission line capacity to support them, resulting in a huge start-up cost as large sections of transmission lines would have to be upgraded. Supposedly the energy from wind farms in places like Nebraska would enter the national power grids, and supposedly at that point it is impossible to track where the energy is used.

But I don't think the neighborhood association would go for one in my back yard.

Maybe not, but how about one of these on your house? I've seen them on the building mentioned in the article, they aren't nearly as conspicuous.

[Bill Glasheen]

how about one of these on your house? I've seen them on the building mentioned in the article, they aren't nearly as conspicuous.

Beauty is in the eye of the beholder I suppose. I have one word for that thing. FUGLY!!!!

I'd a lot rather have one of these.



Meanwhile... This is the closest thing to something that would produce a reasonably significant amount of energy from wind. A bit of an eyesore for sure, but it would fit well in a remote landscape.

REGENEDYNE Wind Turbine

A good application would be for something like the city of Charlottesville, VA, which is in a valley. You could stick one of these up on Brown's or Carter's Mountain, which overlook Charlottesville. (Note the 3 white UVa Medical Center buildings in the foreground, and the Blue Ridge Mountains in the background.)



Now Thomas Jefferson may be rolling in his grave when/if it interferes with his pristine view from Monticello, but at least it could work.

- Bill

[f.Channell]

TJ loved gadgets, he'd order up one and put it right in.

F.

[PreyingMantis]

Hey I would sport one of these on my property! With all the land I own, it sure would be a hell of a conversation piece at a party
However with the monster tornadoes that role through here... well um... I wonder if they could with hold the force?

Maybe not, but how about one of these on your house? I've seen them on the building mentioned in the article, they aren't nearly as conspicuous.

[/quote]

[PreyingMantis]

REGENEDYNE Wind Turbine

Yes I would support this structure although they are not as pretty as a whipping windmill. We have to remember the world economy needs a change, a positive change. It takes risks of intelligent investments to create future stability. We all need to wake up and get off of our video game asses and start preparring for the future for our humanity to survive for generations to come.

[Bill Glasheen]

REGENEDYNE Wind Turbine

Yes I would support this structure although they are not as pretty as a whipping windmill. We have to remember the world economy needs a change, a positive change. It takes risks of intelligent investments to create future stability. We all need to wake up and get off of our video game asses and start preparring for the future for our humanity to survive for generations to come.

That particular wind turbine is the real deal. I've pondered the problem for years, noting how a typical propeller wind turbine only captures a small amount of the wind energy. It's hard to imagine them getting much more creative and efficient than this design. I love the elegant simplicity. Note how the "sails" funnel so much wind into a small area in much the same way that a large dish antenna captures radio waves from a large area and focuses them on a point.

As the original article you cited mentioned, these plants only produce when the wind blows. Some places - like near the ocean or on top of a mountain - are good for wind. Other places not so much. So while it's not a cure to our energy woes, it's certainly one piece of the big puzzle.

And it is kinda cool!

TJ loved gadgets, he'd order up one and put it right in.

F.

You know what? You are absolutely right. I stand corrected on the "roll in his grave" comment.

- Bill

[PreyingMantis]

(As the original article you cited mentioned, these plants only produce when the wind blows. Some places - like near the ocean or on top of a mountain - are good for wind. Other places not so much. So while it's not a cure to our energy woes, it's certainly one piece of the big puzzle.)

And it is kinda cool!


- Bill

Ok Mr. Scientist...what is a genius way to capture the wind way up above and localize it to flat land? There must be some enginneered way to make this happen. I know it can happen. Nothing is impossible with the right research group all on the same page. So what is a theoretic way this could happen?

[Bill Glasheen]

OK, Mary Ann. Now you're dipping into a part of my education (in electrical engineering) that I mothballed a long time ago. But wait... Yep... It's still there.

The secret is actually in the video I posted. (REGENEDYNE Wind Turbine)

By design, the entire site is centralized into one location. And in most configurations, a typical installation would require approximately 100 acres of land. This consolidation not only improves on efficiency, but can also save on land resources. ... With on-site power storage and conversion, the Regenedyne system is completely self-sufficiant and grid ready.

Translation? This is no different than a typical hydroelectric source of power (a dam) where you produce the power where there is energy (in the form of large volumes of elevated water) and load it into the electrical grid. "The grid" is the mixture of transmission lines and transformer stations that carry power from point A to point B through the area of interest (high voltage lines) and change the voltage to a usable level (via transformers) at the point of use.

- Bill

[PreyingMantis]

Translation? This is no different than a typical hydroelectric source of power (a dam) where you produce the power where there is energy (in the form of large volumes of elevated water) and load it into the electrical grid. "The grid" is the mixture of transmission lines and transformer stations that carry power from point A to point B through the area of interest (high voltage lines) and change the voltage to a usable level (via transformers) at the point of use.

- Bill

Ok lets go back a reply or two. So I see and understand your concerns and observations of how this can be possible in obvious locations that wind occurs. What about the places it doesn't? Is there a way in higher altitudes resulting in a satellite maybe, or something to that matter that could transfer the energy supply to non-windy locations for the benefit or energy production?

[Bill Glasheen]

Is there a way in higher altitudes resulting in a satellite maybe, or something to that matter that could transfer the energy supply to non-windy locations for the benefit or energy production?

Think of "the grid" as one massive bank where deposits can be made at one place and drawn from the next. So you can put energy in at windy point A and withdraw it at non-windy point B - as long as both locations are on the grid. There will be losses across long distances, which is why you want to distribute the power sources. But it is possible to spread the electrons around, so to speak.

Bottom line is that this is one of many potential future energy sources. Got water? Build a dam. Got wind? Set up one of these wind turbines. Got radiation? Go nuclear.

Wind will be a small, small part of the big picture. But every little bit helps. If you live on the ocean or near a small mountain (Carter's mountain) or near the Santa Anna desert or some other reliably windy place, this is a logical source of power to add onto the grid.

Put one outside Congress and DC will have all the power it needs.

- Bill