With the growing demand for alternative power sources, scientists and different manufacturers are starting to piece together different types of green equipment. You now have solar powered devices small enough to run a laptop computer and large enough to power entire office buildings. Solar and wind powered jets have soared through the sky and incredible heights and speeds, all while leaving every drop of oil and gas on the ground. These incredible advancements are made possible by peoples’ dedication to save our planet. But even though we have new devices which create energy in many different ways, some have stayed the exact same for many years. 

A wind turbine is a very simple piece of equipment. It is a rotating machine that converts the kinetic energy in wind into mechanical energy for our use with everyday electrical needs. If the mechanical energy is used directly by machinery, then the device is referred to as simple a windmill. But if the mechanical energy is then converted to electricity, the machine is called a wind turbine. Wind machines have been around since 200 B.C., when the Persians used them for grinding grain. They then moved from the Roman’s, to the Dutch, and ultimately to Cleveland, Ohio where the first windmill was used to produce electricity.

What a lot of people don’t know is that wind energy is also a form of solar energy. The sun’s radiation heats different parts of the earth at different rates. This in turn causes portions of our atmosphere to warm differently. The hot air rises and reduces the atmospheric pressure of the earth’s surface. And when the cooler air is drawn in to replace it, the result is wind. A wind turbine system is pretty basic in design. There are only two main designs of turbines: vertical-axis and horizontal-axis. Horizontal wind turbines are the most common, constituting nearly all of the utility –scale turbines in the global market. Utility-scale turbines produce 100 kilowatts kW, or larger.

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Urban wind power systems aren’t new. Way back in the mid-70’s, the first rooftop windmill was installed on top of a NY City co-op building. The wind turbine generated enough electricity monthly - 200 kilowatt-hours - to power the building with enough electricity left over to deliver some to the Northeast power grid. So why didn’t urban wind generation catch on? For one thing, the technology was primitive compared to today’s. The early models were noisy and vibrated enough to be felt throughout the buildings. They looked like propellers on sticks to some people and weren’t aesthetically pleasing at all.

Things have certainly changed. When Chicago turned to Bil Becker, of Aerotecture International, http://www.aerotecture.com, he was able to provide the city with vertical-axis wind turbines that are almost beautiful. More like modern sculptures, these new rooftop turbines are able to generate electricity no matter the wind direction. Unlike horizontal-axis turbines, they can do that even when the wind is blowing with 100 mph gusts! Their price — under $4,000 and falling –make them accessible to the residential market also. Thanks to new design technology, vertical-axis turbines are almost no hazard to wildlife, they don’t vibrate at all and produce very little noise.

With very little fanfare, these rooftop arrays have multiplied at an increasing rate over the last decade, according to the American Wind Energy Association, and the industry is expanding exponentially. Phillipa Rogers, a spokesperson for Quiet Revolution, says, “We can’t make the turbines fast enough.” Company president, Phil Watkins, sees more than 40,000 turbines distributed by next fall. (http://www.plentymag.com/features/2007/09/a_mighty_wind.php)

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The initial cost of a small wind turbine that will power an average home runs from $40,000 to $50,000, which is a significant investment. Why then do homeowners in 47 states have these windmills installed on towers on their property? For most of them, conventional electrical costs of over ten cents per kilowatt and plans to stay in their home long-term make it likely that they’ll more than pay for their windmill. They may very well save money over the monthly cost from their power company.Although there are drawbacks to home windmills, there are many benefits and the drawbacks can be overcome with some careful planning and research. The most important consideration, as you may imagine, is the average wind speed in your area. If there isn’t a steady source of wind, a windmill is not a good investment. Better to opt for solar or geothermal. If there is a steady wind, then the next consideration is probably the tall tower that you have to either erect yourself or have built for the wind turbine.

Some homeowners feel capable of doing this, especially if they purchase kits that allow you to build the tower in sections and then tilt it to put it up. Most, however, elect to hire qualified builders to put up the tower, and perhaps the turbine also. Proper installation will insure that your turbine is facing in the right direction and safely and securely fastened to the tower. At http://www.housingzone.com/probuilder/article/CA6406833.html there are recommendations for installing a home wind generator and links to wind power resources. And for further information, including plans, visit http://www.awea.org/smallwind.

But before you even unpack the turbine, you should make sure that its site is far enough from your dwelling to eliminate the noise issue. At least 160 feet is recommended. This is the one complaint that crops up again and again from homeowners who installed their unit on their garage roof or their home’s roof. Most small wind powered turbines are about as loud as the average clothes washer. If you take that into consideration when you are choosing a site for your generator, you’ll save yourself a lot of problems down the road.

Most homeowners opt to have their generator tied into their local utility’s line so that they can sell their excess electricity. This can help offset the cost of the generator over the years. And since the power is being generated, why not profit from it rather than wasting it? Other homeowners, including those who live too far away from power lines, forego tying into the power grid and just power their house and outbuildings with their wind powered generator. There are many places all over the world, even in developed countries, where running a line from the nearest pole to a homeowner’s dwelling would be cost-prohibitive.

If you’re going to sell your excess electricity, it’s important that you meet with your power company’s representatives and arrange for them to be on site when the generator is connected to the grid. Of course, it’s important also that you’re aware of and follow all local ordinances. A trip to your town building inspector or the appropriate official is imperative. And because of the height of the tower, home windmill installations are more suited to rural locations where landowners have enough acreage to isolate their unit from neighbors’ views.

The last point to consider is maintenance. It’s really important to purchase a tower unit that can be laid down by crane in the event that the windmill needs repair or maintenance. Of course, when repairs are made or the unit undergoes maintenance, it’s very important that the electricity is disconnected. Industry insiders predict that smaller, more compact wind powered generators will supplant the tall towers and propeller-type windmills, and that probably will happen in the future. As of now though, throughout the world, the tall towers and whirly-bird generators still dot the landscape, powering lights and appliances for satisfied homeowners.

Wind turbines come in all sizes from small windmills designed to power fountains and garden lights to larger home wind turbines up to giant turbines whose blade area covers the space of 2 soccer fields. The largest turbines are usually grouped into wind farms and more and more often are used in offshore installations, especially in Europe where wind power generation is a larger part of total power generation than it is anywhere else in the world. Germany and Spain lead the world in percentage of wind power to conventional power but China, the US, Canada and France are experiencing very rapid growth which makes them major players in wind power also.The largest wind turbine in the world is currently the REPower 5M. According to RE Power’s web site at http://www.repower5m.com/index_flash_uk.htm the 5M has a rated output of 5 megawatts, a rotor diameter of 126 meters, and a hub height of around 90 meters at sea and 120 meters on land. This giant wind turbine is being used to power several wind farm projects including a demonstration project off the coast of Scotland.

To reduce weight, the three rotor blades are made from an innovative glass/carbon fiber hybrid fabric that is held together by synthetic resins. To further reduce weight, the 5M’s die cast rotor shaft is hollow.

Another innovation is a gearbox that may be repaired or removed without having to take apart the rotor. This could mean a significant saving in repair cost and downtime. To deal with one of the most persistent problems with any wind turbine system, wind turbulence, the nacelle, which also holds the inverter and transformer for the 5M, has 8 geared motors for tracking the wind. To keep the nacelle facing into the wind, the 5M is equipped with eight hydraulic brake calipers. As a backup, there are also electromagnetic disc brakes. This greatly minimizes problems with turbulence-related damage.

The 5M has many options: a helicopter platform for offshore sites and elevators to lift goods and workers to the top of the tower. The towers themselves may be made from tubular steel, concrete or a hybrid of both steel and concrete. Every tower is equipped with communication capacity and, of course, cables for energy transmission.

Safety is a priority with the 5M both for workers and the installation itself. Automatic high capacity fire extinguishers are programmed to operate when fire is detected and lightning protection - a must in the stormy offshore environment - is built in. All safety systems have backups built into the design. This means that the 5M has optimum power production with few offline instances.

No doubt, other giant wind turbines will come on line within the near future, especially since several companies, including Siemens and GE have announced wind power projects. At http://www.powergeneration.siemens.com/press/press-releases/search.htm Siemens has information about projects they’ve recently been awarded in Denmark and Spain.

As technology improves wind turbine design and technology, and more countries turn to wind to power their homes and factories, giant wind turbines will continue to play a big part in the wind power market. Siting them offshore ameliorates the problems of aesthetics, especially if they are out of sight of land.

Environmental concerns, while still a factor, are not as relevant. While the cables emit electromagnetic waves which are a problem for sharks and rays, technology has yielded designs that help to overcome this. The impact on the seabed is taken into consideration and every effort is made to make it as minimal as possible. Further innovations will emerge as designers find new ways to make the giant wind turbines as environmentally friendly as possible. When everything is taken into consideration, including how much pollution and environmental damage the wind farms prevent by replacing conventional power generating technologies such as coal and gas, it seems apparent that giant wind turbines are a reasonable alternative energy source.

The basis of wind power is both simple and complex. For thousands of years, humans have harnessed the wind to grind their grain, sail their boats and pump water. The windmill was once a common site on farms and in the countryside all over the US and Europe. The windmill is national icon for the Netherlands, where it was used to pump water from farmland reclaimed from the sea. But starting with the Industrial Revolution, fossil fuel power plants and the electricity they produced replaced windmills and wind pumps.It wasn’t until the threat of global warming and a more eco-conscious public that wind power became more than an oddity pursued by backyard tinkerers and eccentric inventors. The way wind power works is simple. The blades catch the wind, which turns them and the hub they’re attached to. The hub turns a gearshaft which turns inside a generator thus producing electricity. How much electricity depends on both the size of the blades and the speed of the wind. The cost of operating wind power generators is slightly higher than or similar to conventional technologies, although it can be cheaper depending on the country.

Wind power while not totally benign, has advantages over the technologies in use now to produce electricity. Opponents of wind power often cite the toll it takes on birds and bats. But according to http://www.world-wire.com/news/0612040002.html even in Denmark, where over 10% of electricity production is generated by wind turbines, power lines kill many more birds. This issue is also being addressed by designers and has been all but eliminated in the new vertical axis and aeroturbine windmills. And wind power has much less of an effect on other wildlife and may even be beneficial.

When compared to coal and other fossil fuels, which make up 70% of US electricity generation, wind power emits no mercury, sulfur dioxide, acid rain, nitrogen oxide, or greenhouse gases. Rivers don’t have to be dammed for wind power and it produces no nuclear waste like nuclear power plants do. Wind power will never be depleted like fossil fuels and nuclear energy. It’s free for the taking, like solar power, although the equipment needed to convert wind to electric is still expensive. Industry experts expect that to change as wind power becomes more pervasive and accepted around the world.

Large installations of windmills, often called wind farms, generate enough electricity to power hundreds of houses. However they also generate the most controversy, because of noise, aesthetic impact and the threat to birds and bats. As mentioned earlier, designers are addressing these problems and new technologies are making wind power safer, quieter and less damaging to avian populations. Vertical axis turbines, pose almost no danger to birds, produce almost no noise or vibration and may be installed in urban areas. At http://www.plentymag.com Plenty Magazine reports that they are being tested in Chicago and other cities, where the preliminary reports are very favorable. There are even small home wind turbines which can be installed on roofs. These generate power for the household without linking to the power grid.

Experts believe that up to 20% of US electrical power generation could be accomplished with wind power. Canada, Australia and European countries have already implemented their own far reaching programs to replace a percentage of their conventional power plants with wind power. As the self-proclaimed windiest country in Europe, England is particularly well-suited to wind power and has been aggressively pursuing installations of wind farms for years. China has the first Mag-Lev wind power installation and has plans for future large-scale wind power generating facilities.

The several-hundred-billion dollar industry of power production through wind turbines is flourishing and promises to be even stronger in future. What with carbon offsetting and governments coming on board the global warming initiatives, wind power can only grow as the price per kw falls closer to and even lower than a kw produced by coal or gas.