Wind energy jobs

6:08 PM 1 Comment

The Wind Energy Jobs category is the second fastest growing in the green energy generation segment, and include many sub-categories, and a multitude of job types. Examples of wind energy sub-categories include:

1. Research and development jobs in wind turbine blade and rotor technology; these jobs often require a higher-education degree (bachelor's or master's). Great examples of employers in this category include Vestas and Boulder Windpower
2. Wind turbine manufacturing jobs. Employers in this category include large wind turbine manufacturers such as Clipper Windpower, and small wind turbine manufacturer XZERES.
3. Utility-scale wind turbine installation for large wind farms. A great example of employers in this category is Signal Wind Energy
4. Wind turbine maintenance and repair. Great examples of employers in this category are Horizon Wind Energy and First Wind.
5. Below are some of the largest and most well-known Wind trade and non-profit associations:

• The American Wind Energy Association (AWEA) is the leading wind trade association.
• The Wind Coalition is a non-profit association designed to promote the development of wind energy in the South Central states.
• Windustry promotes progressive renewable energy solutions and empowers communities to develop and own wind energy as an environmentally sustainable asset.



Wind energy jobs

Here are some of our recent stories about wind energy jobs:
American Offshore Wind: 300,000 Green Jobs and $200B Potential.
Venture Capitalists Bet Big on Danotek's Wind Turbine Generator.
Siemens' Wind Unit to Create Green Jobs In Oklahoma.
Wind Power Creates Good American Green Jobs.
Kern County, CA, to Get More Wind Jobs.
A week after GE's Largest Wind Turbine Order, Siemens Gets Its Largest Too.
Nordic Windpower to Relocate to Kansas City, Create 200 Jobs.

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Small wind turbines and basic components

3:53 PM No Comments

Wind turbines used to generate electricity come in a wide variety of sizes. Large wind turbines, which are usually installed in clusters called wind farms, can generate large amounts of electricity. Large wind turbines may even produce hundreds of megawatts (MW) of electricity - enough to power hundreds of homes. Small wind turbines which are generally defined as producing no more than 100 kW of electricity, are designed to be installed at homes, farms and small businesses either as a source of backup electricity, or to offset use of utility power and reduce electricity bills. Very small wind turbines (20-500 watt units) are used to charge batteries for sail boats and other recreational uses.

Wind turbine.

A small wind energy system could prove to be a practical and economical source of electricity for your home or farm if some or all of the following are true:

• Your property has a good wind resource.
• Your property is at least one acre in size.
• Your local zoning ordinances allow wind turbines.
• Your electricity bills tend to be high.
• Your property does not have easy access to utility lines, i.e. off electrical power grid.
• You are comfortable with making long-term investments.
• Turbine is 250-300 m away from your neighbour's house (closer for small turbines i.e. 1 kW).

Types of Wind Turbines

There are two basic types of wind turbines: horizontal axis wind turbines and vertical axis wind turbines. Horizontal axis turbines (more common) need to be aimed directly at the wind. Because of this, they come with a tail vane that will continuously point them in the direction of the wind. Vertical axis turbines work whatever direction the wind is blowing, but require a lot more ground space to support their guy wires than horizontal axis wind turbines.

 Two basic wind turbines, horizontal axis and vertical axis.

Components of Wind Energy Systems

The basic components of a typical wind energy system are shown on following figure.

Components of a wind energy system.

 These basic components include:

• A rotor, consisting of blades with aerodynamic surfaces. When the wind blows over the blades, the rotor turns, causing the generator or alternator in the turbine to rotate and produce electricity.
• A gearbox, which matches the rotor speed to that of the generator/alternator. The smallest turbines (under 10 kW) usually do not require a gearbox.
• An enclosure, or nacelle, which protects the gearbox, generator and other components of the turbine from the elements.
• A tail vane or yaw system, which aligns the turbine with the wind.

If you plan on building a horizontal axis wind turbine, you will need a tower on which to mount the turbine (vertical axis turbines are usually built on the ground).

Several types of towers are available:

• Guyed lattice towers, where the tower is permanently supported by guy wires. These towers tend to be the least expensive, but take up a lot of space on a yard. A radio broadcast tower is a good example of a guyed lattice tower.
• Guyed tilt-up towers, which can be raised and lowered for easy maintenance and repair.
• Self-supporting towers, which do not have guy wires. These towers tend to be the heaviest and most expensive, but because they do not require guy wires, they do not take up as much space on a yard.

An important factor in how much power your wind turbine will produce is the height of its tower. The power available in the wind is proportional to the cube of its speed. This means that if wind speed doubles, the power available to the wind generator increases by a factor of 8 (2 x 2 x 2 = 8). Since wind speed increases with height increases to the tower height can mean enormous increases in the amount of electricity generated by a wind turbine.

 Relationship between wind speed and wind power.

It has been recommended that towers be 24-37 m (80- 120 ft) high. Installing a wind turbine on a tower that is too short is like installing a solar panel in a shady area. At a minimum, mount a wind turbine high enough on a tower that the tips of the rotor blades remain at least 9 m (30 ft) above any obstacle within 90 m (300 ft).

Make sure to check local laws about height restrictions for wind turbine towers. Use a tower approved by the wind turbine manufacturer otherwise the warranty on the turbine may become invalid. Also ensure the tower is connected to an underground metal object to ground the tower in case of a lightning strike.

You need a disconnect switch that can electrically isolate the wind turbine from the rest of the wind energy system. An automatic disconnect switch is necessary to prevent damage to the rest of the system in case of an electrical malfunction or a lightning strike. It also allows maintenance and system modifications to be safely made to the turbine. There are other system components you may choose or need to purchase. You may need batteries to store excess energy generated by the wind turbine. Because energy is stored in batteries as DC power, you may need an inverter to convert power from the batteries to the AC power required to run electrical appliances in your home.

 Diagram of a grid-tied wind electric system.

If your home or farm is connected to the power grid on windier days you may be able to "sell" excess power generated by your wind turbine to your utility. Then, at other times when your turbine cannot generate all the power you need, you would buy power from the grid. This concept is called "net metering", or "net billing". Net metering is currently unavailable in most parts of Ontario, but may be available fall 2003. Contact your local utility or Hydro One.

Even if net metering is unavailable, you might be able to reduce your power bills by using the electricity you generate using a grid-connected wind turbine. If you do this, then you would not have to buy as much electricity from your utility.

If you do connect your wind turbine to the grid, your utility will require a transfer switch between the wind turbine and the utility line as a well as a two-way meter to keep track of the energy you have stored in and taken from the power grid. It is very important that your wind generator meets certain standards and that it does not pose a risk to your utility's personnel or equipment. It is also important that the quality of power coming from your turbine adequately matches the electrical characteristics in your utility's power grid.

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Vestas Wind Turbine Crash

3:17 PM 1 Comment

A small wind farm in County Donegal, Ireland, has been closed down after one its Vestas V52 turbines collapsed in high winds.Vestas has stopped production of the V52.

Vestas V52

In a statement, Vestas confirmed the incident occurred on Friday afternoon. It said the wind speeds at the time were around 90 kilometres per hour and an investigation is under way into the causes of the incident.

The project is owned by Irish utility Energia.

A spokesman said: "Vestas takes safety extremely seriously. A thorough investigation will be conducted to establish the root cause of the incident. Until this has been conducted, Vestas cannot speculate on the cause of the incident."

In June 2012, Vestas said it was ending production of the the V52 and V60 850kW machines. In a statement the company said it was closing its factory in Hohhot, Inner Mongolia Autonomous Region and cut 300 jobs.

Vestas said it took the decision as it projected a low market for the kW range. It said it would honour all existing contracts and continue servicing the turbines.

To read more about wind turbine accidents : wind turbine accidents 

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Wind Generator

6:17 PM 1 Comment

The wind turbine generator converts mechanical energy to electrical energy.
Wind turbine generators are a bit unusual, compared to other generating units you ordinarily find attached to the electrical grid. One reason is that the generator has to work with a power source (the wind turbine rotor) which supplies very fluctuating mechanical power (torque).
These pages assumes that you are familiar with the basics of electricity, electromagnetism, and in particular alternating current. If any of the expressions volt (V), phase, three phase, frequency, or Hertz (Hz) sound strange to you, you should take a look at the Reference Manual on Electricity and read about alternating current, three phase alternating current, electromagnetism and induction before you proceed with the following pages.

Wind genearator

Generating Voltage (tension)
On large wind turbines (above 100-150 kW) the voltage (tension) generated by the turbine is usually 690 V three-phase alternating current (AC). The current is subsequently sent through a transformer next to the wind turbine (or inside the tower) to raise the voltage to somewhere between 10,000 and 30,000 volts, depending on the standard in the local electrical grid.
Large manufacturers will supply both 50 Hz wind turbine models (for the electrical grids in most of the world) and 60 Hz models (for the electrical grid in America).
Cooling System
Generators need cooling while they work. On most turbines this is accomplished by encapsulating the generator in a duct, using a large fan for air cooling, but a few manufacturers use water cooled generators. Water cooled generators may be built more compactly, which also gives some electrical efficiency advantages, but they require a radiator in the nacelle to get rid of the heat from the liquid cooling system.
Starting and Stopping the Generator
If you connected (or disconnected) a large wind turbine generator to the grid by flicking an ordinary switch, you would be quite likely to damage both the generator, the gearbox and the current in the grid in the neighbourhood.
You will learn how turbine designers deal with this challenge in the page on Power Quality Issues , later.

Small wind generator

Design Choices in Generators and Grid Connection
Wind turbines may be designed with either synchronous or asynchronous generators, and with various forms of direct or indirect grid connection of the generator.
Direct grid connection mean that the generator is connected directly to the (usually 3-phase) alternating current grid.
Indirect grid connection means that the current from the turbine passes through a series of electric devices which adjust the current to match that of the grid. With an asynchronous generator this occurs automatically.

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Wind Turbines and Power Quality Issues

11:55 AM 1 Comment

The buyer of a wind turbine does not need to concern himself with local technical regulations for wind turbines and other equipment connected to the electrical grid. This responsibility is generally left to the turbine manufacturer and the local power company.
For the people who are technically minded, we go into some of the electro-technical issues involved in connecting a turbine to the grid on this page.

Power quality

The term "power quality" refers to the voltage stability, frequency stability, and the absence of various forms of electrical noise (e.g. flicker or harmonic distortion) on the electrical grid. More broadly speaking, power companies (and their customers) prefer an alternating current with a nice sinusoidal shape, such as the one in the image above. 

Starting and Stopping a Turbine
Most electronic wind turbine controllers are programmed to let the turbine run idle without grid connection at low wind speeds. (If it were grid connected at low wind speeds, it would in fact run as a motor). Once the wind becomes powerful enough to turn the rotor and generator at their rated speed, it is important that the turbine generator becomes connected to the electrical grid at the right moment.
Otherwise there will be only the mechanical resistance in the gearbox and generator to prevent the rotor from accelerating, and eventually over-speeding. (There are several safety devices, including fail-safe brakes, in case the correct start procedure fails).

Soft Starting with Thyristors
If you switched a large wind turbine on to the grid with a normal switch, the neighbours would see a brownout (because of the current required to magnetize the generator) followed by a power peak due to the generator current surging into the grid. You may see the situation in the drawing in the accompanying browser window, where you see the flickering of the lamp when you operate the switch to start the wind turbine. The same effect can possibly be seen when you switch on your computer, and the transformer in its power supply all of a sudden becomes magnetized.
Another unpleasant side effect of using a "hard" switch would be to put a lot of extra wear on the gearbox, since the cut-in of the generator would work as if you all of a sudden slammed on the mechanical brake of the turbine.

Grid connection

To prevent this situation, modern wind turbines are soft starting, i.e. they connect and disconnect gradually to the grid using thyristors, a type of semiconductor continuous switches which may be controlled electronically. (You may in fact have a thyristor in your own home, if you own a modern light dimmer, where you can adjust the voltage on your lamps continuously).

Thyristors waste about 1 to 2 per cent of the energy running through them. Modern wind turbines are therefore normally equipped with a so called bypass switch, i.e. a mechanical switch which is activated after the turbine has been soft started. In this way the amount of energy wasted will be minimized.

Weak Grids, Grid Reinforcement
If a turbine is connected to a weak electrical grid, (i.e. it is vary far away in a remote corner of the electrical grid with a low power-carrying ability), there may be some brownout / power surge problems of the sort mentioned above. In such cases it may be necessary to reinforce the grid, in order to carry the fluctuating current from the wind turbine.
Your local power company has experience in dealing with these potential problems, because they are the exact mirror-image of connecting a large electricity user, (e.g. a factory with large electrical motors) to the grid.

Grid connection

Flicker
Flicker is an engineering expression for short lived voltage variations in the electrical grid which may cause light bulbs to flicker. This phenomenon may be relevant if a wind turbine is connected to a weak grid, since short-lived wind variations will cause variations in power output. There are various ways of dealing with this issue in the design of the turbine, mechanically, electrically, and using power electronics.

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Interesting Wind Energy Facts

8:05 PM 1 Comment

1. At the current growth rate, U.S. wind energy developers install two new wind farms per week.

2. Wind mills have been in use since 2000 B.C. and were first developed in China and Persia.

3. Wind power is currently the fastest-growing source of electricity production in the world.

4. Google has invested $5 billion in a new underwater transmission line to connect offshore wind farms in the Atlantic Ocean with 1.9 million households on the East Coast.

Offshore wind farm

5. A single wind turbine can power 500 homes.

6. Roscoe Wind Farm in Texas is the world’s largest wind farm with 627 turbines generating 781.5 MW of electricity.

7. More than one-third of all new generating capacity installed in America since 2007 is from wind power.

8. There’s enough on-shore wind in America to power the country 10 times over.

Interesting wind turbines

9. U.S. wind power produces as much electricity as nearly 10 nuclear power plants.

10. Most wind turbines (95%) are installed on private land.

11. Modern wind turbines produce 15 times more electricity than the typical turbine did in 1990.

12. At times, wind energy produces as much as 25% of the electricity on the Texas power grid.

Wind turbine and birds

13. American wind power is a $10 billion a year industry.

14. Unlike nearly every other form of energy, wind power uses virtually no water.

15. By 2030, U.S. wind power will save nearly 30 trillion bottles of water.

16. At times, wind power produces as much as 45% of the electricity in Spain.

Interesting wind farm

17.Wind energy became the number-one source of new U.S. electricity-generating capacity for the first time in 2012, providing some 42% of all new generating capacity. In fact, 2012 was a strong year for all renewables, as together they accounted for more than 55% of all new U.S. generating capacity.

18.During the fourth quarter of 2012, Texas led the nation in new wind installations (with 1,289 megawatts), followed by California, Kansas, Oklahoma and Iowa.

19. U.S. renewable energy consumption increased by 6% in 2010, with wind energy as the source of 11% of the total renewable energy consumption.

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Size of Wind Turbine

7:39 PM No Comments

Following figure shows trends by year of the typical largest turbine sizes targeted for mainstream commercial production. Megawatt turbines existed in the 1980s but almost all were research prototypes. An exception was the Howden 1 MW design (erected at Richborough in the UK), a production prototype, which was not replicated due to Howden withdrawing from the wind business in 1988. Although there is much more active consideration of larger designs than indicated in figure, no larger turbines have appeared since 2004.
To read more about new wind turbine trends see: Wind Turbine Trends 

To enlarge the figure click

Up until around 2000 an ever-increasing (in fact mathematically exponential) growth in turbine size over time had taken place among manufacturers and was a general industry trend. In the past three or four years, although there is still an interest in yet larger turbines for the offshore market, there has been a slowdown in the growth of turbine size at the center of the main, land-based market and a focus on increased volume supply in the 1.5 to 3 MW range.

The early small sizes, around 20-60 kW, were very clearly not optimum for system economics. Small wind turbines remain much more expensive per kW installed than large ones, especially if the prime function is to produce grid quality electricity. This is partly because towers need to be higher in proportion to diameter in order to clear obstacles to wind flow and escape the worst conditions of turbulence and wind shear near the surface of the earth. But it is primarily because controls, electrical connection to grid and maintenance are a much higher proportion of the capital value of the system in small turbines than in larger ones. 

To enlarge the figure click

Onshore technology is now dominated by turbines in the 1.5 and 2 MW range. However, a recent resurgence in the market for turbines of around 800 kW is interesting and it remains unclear, for land-based projects, what objectively is the most cost-effective size of wind turbine. The key factor in continuing quest for size into the multi-megawatt range has been the development of an offshore market. For offshore applications, optimum overall economics, even at higher cost per kW in the units themselves, requires larger turbine units to make up for the proportionally higher costs of infrastructure (foundations, electricity collection and sub-sea transmission) and number of units to access and maintain per kW of installed capacity.

Following figure shows the development of the average sized wind turbine for a number of the most important wind power countries. It can be observed that the average size has increased significantly over the last 10-15 years, from approximately 200 kW in 1990 to 2 MW in 2007 in the UK, with Germany, Spain and the USA not far behind.

 As shown, there is a significant difference between some countries: in India, the average installed size in 2007 was around 1 MW, considerably lower than in the UK and Germany (2,049 kW and 1,879 kW, respectively). The unstable picture for Denmark in recent years is due to the low level of turbine installations.
To learn more about Germany wind energy see: Germany wind energy potential

To enlarge the figure click

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Wind Turbine Costs

7:21 PM No Comments

Wind turbines, including the costs associated with blades, towers, transportation and installation, constitute the largest cost component of a wind farm, typically accounting for around 75% of the capital cost. Wind turbines tend to be type-certified for clearly defined external conditions. This certification is Source: Wind Directions, January/February 2007 requested by investors and insurance companies, and states that wind turbines will be secure and fit for their purpose for their intended lifetime of around 20 years for onshore projects and 25 years for offshore. The following illustration shows the main sub-components that make up a  wind turbine, and their share of total wind turbine cost. Note that the figure refers to a large turbine in the commercial market (5 MW as opposed to the 2 to 3 MW machines that are commonly being installed). The relative weight of the sub-components varies depending on the model.

To make the illustration bigger :  Wind turbine costs

Wind turbines are priced in proportion to their swept rotor surface area and generally speaking in proportion to roughly the square root of their hub height. The size of the generator of a wind turbine plays a fairly minor role in the pricing of a wind turbine, even though the rated power of the generator tends to be fairly proportional to the swept rotor area. The reason for this is that for a given rotor geometry and a given tip speed ratio, the annual energy yield from a wind turbine in a given wind climate is largely proportional to the rotor area. In relation to tower heights, the production increases with the hub height roughly in proportion to the square root of the hub height (depending on the roughness of the surrounding terrain). It should be noted that the generator size of a wind turbine is not as important for annual production as the swept rotor area of the turbine. This is because on an optimized wind turbine, the generator will only temporarily be running at rated (peak) power. It is therefore not appropriate to compare wind turbines with other power generation sources purely on the basis of the installed MW of rated generator power. One has to keep in mind that the energy of a wind turbine comes from the swept rotor area of the wind turbine. The swept rotor area is thus in some sense the field from which the energy of the wind is harvested. 

Wind lamp

To read more about economic facts about wind turbines, see : The cost of energy generated by wind

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Wind Energy

7:38 PM 1 Comment

A wind turbine is a machine made up of two or three propeller-like blades called the rotor. The rotor is attached to the top of a tall tower. As the wind blows it spins the rotor. As the rotor spins the energy of the movement of the propellers gives power to a generator. There are some magnets and a lot of copper wire inside the generator that make electricity.

Wind farm

Because winds are stronger higher up off the ground, wind turbine towers are about 30 meters tall to allow the rotor to catch more wind energy. The turbines are built with a device that turns the rotor so that it always faces into the wind.

Just one wind turbine can generate enough electricity for a single house or the electrical energy to pump water or to power a mill which grinds grain. The electrical energy can also be stored in batteries.

Wind farms

Wind farms are places where many wind turbines are clustered together. They are built in places where it is nearly always windy. The electricity that is generated at a wind farm is sold to electricity companies that provide the electricity to people living in cities and towns.

Wind farm

What are the advantages of wind turbines?

• The energy they generate is renewable. This means that as long as the winds blow there is power to turn the blades of the rotor. 
• Using wind energy means that less fossil fuel (coal and oil) needs to be burned to make electricity. Burning fossil fuel pollutes the atmosphere and adds greenhouse gases to it. 

What are the disadvantages of wind turbines?

• Some people don't like the look of the turbines. They say that they spoil the look of the natural environment.
• Wind turbines make noise.
• Turbines kill birds that fly into them. However collisions are rare and there are reports from Denmark saying that some falcons had built nests on the top of turbine towers. To protect birds however, it is important that wind farms be built away from bird sanctuaries and from the pathways of migratory birds. (Migratory birds are those that fly from cold places in winter to warmer parts of the world)

Wind farm

Here to find how to build your own wind generator?

Homemade 1 kW wind generator

Here to look more about small wind turbines.

Small wind turbine

Go here to read more about wind energy and wind farms.

Why wind energy?

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Wind Turbine Grid Connection

4:03 PM 1 Comment

The wind turbines generate power by rotating a permanent magnet generator which generates three phase AC at the frequency of the turbine's rotation. The AC power from the generator is not only the wrong voltage to be connected to the local power grid, but also, as the wind speed changes so does the rotational speed of the turbine, and therefore the frequency of the power generated. The power from the generator therefore needs to be converted to DC and then fed into a special electronic device called an inverter, to ensure that it is always at the correct frequency and voltage for the local grid. 

Grid connection

Any power you generate will be first used by your own property, thereby saving you the maximum amount possible on your electricity bill. Any excess energy your wind turbine generates, e.g. on windy days or at night, is "spilled" to the power grid and your electricity supplier pays you for it. 

Grid connection

In order to charge your electricity supplier for any energy that you export to the grid, you need to have a new bi-directional electricity meter installed which will work both when you buy (import) and sell (export) electricity. Depending upon your local requirements, there may be additional meters needed to record energy generation to enable a claim for a Government subsidy. 

Shown below is a simplified block diagram of how all the system components are connected in the EU.

Companies however shortly hope to offer an off-grid package which when combined with a battery pack, and optionally solar PV panels and/or a diesel generator will enable the generation of “mains” power where there is no grid connection. For more information on small wind turbines go to small wind turbines.

Grid conection

The inverter also provides essential safety features to control the power output from the turbine, and to automatically switch off the current if the grid connection should fail. This means that should the grid connection fail, the inverters will switch off their output and there is therefore no danger to any maintenance engineers fixing the fault. This does however mean that the wind turbine will produce no power to the property if the mains connection fails. 

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Lightning Protection of Wind Turbines

4:01 PM 1 Comment

With the movement toward green energy, we all have to be thinking about new ways to do things, and wind turbine lighting protection is becoming a big concern. After all, any time you have a tall object sticking up high in the air and standing all by itself, lightning is going to strike it at some point. It is simply a matter of when. But there are some steps you can take to protect your wind turbine from lightning.

Surge protection is essential when it comes to wind turbine lightning protection. Here’s how it works:

· A lightning rod offers some protection to wind turbines, but it’s not enough. Rods only really protect against direct strikes, which are not going to be as common as other dangers from lightning. In order to have complete wind turbine lightning protection, you also need a lightning current arrester.

· Carbon brushes help to ground lightning off of wind turbines, creating an escape path for the lightning to get down to the ground. High quality brushes and brush holders will be able to stand up to the rigours of a lightning strike and protect your wind turbine.

· A class one arrester with spark gap technology is needed to comply with spark gap requirements in most cases. This arrester handles the largest majority of the strike’s power and keeps the class two arrester from overloading.

· A class two arrester connects to the class one arrester and handles all the initial conduction because it is able to respond rapidly to the threat posed by the lightning strike.

Protecting wind turbines from lightning strikes is a very new area of expertise, and it is definitely not one you want to overlook. Whether you’re a major power company with thousands of wind turbines or you’re a home-owner with one turbine in your backyard, you've got to protect your assets.

A lightning rod is a good place to start, but you can’t afford to miss out on the additional protection offered by a carbon brush and brush holder. Power surges won’t be a concern when you have this added insurance against damages.

Some companies offers wind turbine lightning protection. Their carbon brushes are specifically made to protect wind turbines from lightning strikes. They use low resistant grades of material to ensure that the lightning has a very easy path down to the ground that does not involve the overpowering of your wind turbine.

Grounding Brushes & Lightning Protection

Companies offer several different carbon brushes for grounding applications. The most popular grounding brush is used as a shaft grounding assembly that diverts static and induced electric currents in motor shafts away from the bearings, protecting them from pitting and damage. Check out the Bearing Protector which is a brush and holder kit that can be easily installed on the end of the motor shaft. Shaft grounding for use on Variable Frequency Drives (VFD) is the most popular use of the Bearing Protector. VFDs on both AC and DC motor induce harmful electrical current on the motor shaft that results in damage to the bearings. Carbon brushes are also used to provide a path to ground for lightning on Wind Turbine applications. Low resistant grades of material are used to create a sure path to ground for lightning applications. The carbon brush and holder assembly is good insurance against lightning damage. Lightning Protection for Wind Turbines Lightning strikes are a serious concern for wind turbines. Companies offer brush and brush holders that meet the rigorous demands of lightning protection. The brush grades perform well in high surges and are not prone to wear. Low resistivity ensures that electrical currents are directed away from crucial components. Brushes and brush holders are unsurpassed in quality and are a perfect safeguard for your investment.

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Sizing Up Wind Energy and Transportation

6:24 PM No Comments

One of the most popular trends in sustainable living is to go small: Live in a small house. Drive a small car. Have a small carbon footprint. So it seems contradictory that by going big—really big—energy equipment can become better for the environment.

But that's the case with wind turbines, according to a new study by the Swiss Federal Institute of Technology in Zurich.

Over the past 30 years, wind turbines have more than quadrupled in size. The blade diameter of today's models can surpass the length of a football field. In tandem with this growth spurt, land-based turbines in Europe became greener, the researchers concluded.

The report, published in the American Chemical Society's journal,Environmental Science & Technology, looked at the energy it took to build, transport, maintain, and dispose of turbines, as well as the electricity the turbines fed into Europe's power grid.

Turbines became more sustainable over time because larger models produce substantially more energy than smaller versions, the researchers said, but it does not take as much additional energy to manufacture bigger turbines. And as more turbines were built, manufacturers became more experienced and technology improved. With each doubling of wind-turbine manufacturing over time, the Swiss researchers found, the global warming potential per kilowatt-hour of electricity dropped 14 percent.

Marloes Caduff, the lead author, said she was surprised by how much the carbon footprint of the turbines declined over time. "I thought we would see a smaller effect," she said.

The industry, for its part, has tackled many of the challenges of larger turbines—for instance, how to move them from one place to another. Even so, companies believe there will be challenges for further growth in turbine size, even as the industry seeks to further improve their efficiency.

Why Bigger is Better

Bigger turbines reach higher above the earth's surface, where stronger winds blow. This allows them to extract more energy than their predecessors, and to work more efficiently.

In the 1980s, a typical wind turbine was rated with a capacity of about 50 kilowatts of electricity. Today, a large land-based turbine has a capacity of 3,000 kilowatts (3 megawatts). There are developers working on wind turbines as large as 10 MW for offshore installations. But on land, the most common turbines are from  1.5 MW to 2 MW. A 1-MW turbine can power 350 U.S. households for a year, according to Wind Energy America.

Using higher-capacity models reduces the number of turbines needed for a wind farm, says Fort Felker, director of the wind technology center at the U.S. Department of Energy's National Renewable Energy Laboratory in Golden, Colorado. For example, at today's capacities, 500 super-sized turbines could be installed instead of 1,000 smaller ones. By generating more energy with fewer machines, giant turbines can help reduce the price of wind power.

"The larger-size wind turbines result in dramatic reductions in the cost of [wind] energy," Felker said. "The cost has been reduced by a factor of ten or so, from unaffordable levels to where it is right now, able to compete with conventional power sources."

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Germany's Wind Energy Potential

6:54 PM No Comments

Most of Germany’s pro-Energiewende voices think that Germany will far exceed its 2020 target of 35% clean energy. The Heinrich Böll Foundation, a Green think tank, is definitely among them. It argues that Germany could — with the right policies — go 100% renewable by 2050.

But for Germany to do it, argues the report "A European Union for Renewable Energy," there has to be greatly improved cooperation. The EU targets, road maps, and action plans are steps in the right direction, but they fall far short of a comprehensive EU common energy policy.

The report, commissioned by the Heinrich Böll Foundation European Union and prepared by independent experts, argues that most European countries' current energy grids are antiquated, nationally organized, and designed for fossil fuel and nuclear energy sources. The grids are composed mostly of one-way transmission cables connecting large production facilities, like coal-firing plants and nuclear reactors, to residential and commercial hubs.

Since the requisite storage technology is still largely undeveloped, what is needed are "smart," flexible, decentralized grids that crisscross the continent and beyond. In contrast to the "dumb" decentralized networks of the fossil-fuel age, a smart grid is a digital network that links customers with dispersed suppliers, like those operating wind parks and solar installations, through the Internet. The wider-reaching and "smarter" this network is, the better its ability to match weather-dependent supply surpluses and demand needs, both regionally and across borders.

Since grid construction needs as long as ten years to be realized, potential grid investors would need an unshakable commitment to renewable energies to invest in such a costly project. The report underscores a number of measures to get the ball on an all-European system rolling, including a "review" of the EU treaty that stipulates that the national states have full authority to determine their own energy supplies as they wish. Ultimately there must be a guarantee that nationally minded states don't obstruct plans for an European grid system.

As for Europe's current energy markets, they too tend to reflect national priorities and a fossil fuel-dominated system that the EU is supposedly committed to phasing out. The report argues that "open and hidden" subsidies for fossil fuels and nuclear must be abolished in order to even the playing field between renewable and conventional energies.

Moreover, Europe is a patchwork of diverse incentives, subsidies, and related taxes. About two-thirds of EU countries have a feed-in tariff along the lines of Germany's successful model. Its essence is that utilities are required to buy renewable energy from private producers at a higher-than-market price in order to cover the producer's investment in solar modules, wind turbines, biogas plants, or other production installations.

A key recommendation is the gradual harmonization of incentive and subsidy programs based on best practice models, including but not limited to the feed-in tariff. "To make prices within the internal energy market more transparent and attract cross-border investment," says Sascha Müller-Kraenner, the report's chief organizer, "today's systems have to be better connected, based on feed-in tariffs. Remuneration systems like tenders and auctions for big producers such as offshore wind farms can help make today's system even more competitive, but this doesn't mean replacing the most successful elements of the feed-in tariffs."

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