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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