Launch Slideshow

7 Wind Turbines

7 Wind Turbines

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    Cascade Engineering. The rooftop-mountable Swift turbine is designed for urban and suburban homes, starting up in 8-mph winds. It can produce 1,900 kWh per year at a 13.4-mph average wind speed, says the firm, and is never louder than 35 decibels, equivalent to a whisper. The turbine measures 7 feet in diameter. 866.544.5520. www.swiftwindturbine.com.

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    Delta. The 400-watt HAWT generates 50 kWhs per month at 13.4 mph. The rotor, which starts up in 8-mph winds, measures 49.6 inches in diameter. An electronic torque control protects the turbine from blade damage in high winds, says the manufacturer. The firm also makes a 1.0-kW model. 888.979.9889. www.delta-corp.com/windenergy.

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    Endurance Wind Power. S series 5-kW-rated turbines can generate up to 25,000 kWh per year in peak conditions, says the maker. The remote-controlled turbines are available with 90-foot monopoles or 120-foot guyed poles, and can be tilted down for maintenance. The blades are 10 feet long. 888.440.4451. www.endurancewindpower.com.

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    Southwest Windpower. With a rated capacity of 2.4 kW, the Skystream 3.7 pays for itself in five years, says the manufacturer. The controls and inverter are built into the turbine, and poles of varying heights are available. The turbine, which starts up in 8-mph winds, is designed specifically for grid-connected homes. 866.805.9463. www.skystreamenergy.com.

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    Urban Green Energy. The Eddy GT 1-kW-rated vertical-axis turbine fits on a pole or a rooftop and starts up in winds blowing less than 7 mph. The model can tie into the utility grid, can be assembled in less than an hour, and operates quietly, the manufacturer says. It measures about 9 feet high and 6 feet wide. 917.512.9777. www.urbangreenenergy.com.

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    Windspire. Mounted on a 30-foot monopole of recycled high-grade steel, Windspire’s standard turbine produces 2,000 kWh per year in 24-mph winds. The vertical-axis turbine requires a minimum wind speed of
    8.5 mph to operate and is designed to work quietly.  775.852.0200. www.windspireenergy.com.

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    WindTronics. Uniquely designed to generate wind from the blade tips, the Honeywell turbine has no gears and can produce about 18% of the average household’s energy in Class 4 wind conditions, says the manufacturer. The turbine starts up at 2 mph and will turn to face the wind, producing an average of 1,500 kWh per year depending on location and wind conditions, the firm says. Six feet in diameter, the turbine can be mounted on a flat roof, a pitched roof, or a pole. 877.946.3898. www.windtronics.com.

In the backyards of five houses within a 2-mile span in Tarrant County, Texas, small Skystream wind turbines whir quietly atop poles. A prospective client recently approached builder Don Ferrier about making his lakeside house the sixth.

"The owner came to me as most of my clients do, saying, 'We believe building energy efficient only makes sense,'" says the owner of Ft. Worth-based Ferrier Custom Homes.
Ferrier had to build the alternative energy system into the budget but found--as incentives for harnessing wind power whip over the nation in the form of federal tax breaks and state, local, and utility incentives--his client was in for a good deal.

Wind turbine dealers have sold almost 100,000 residential units since 1980, and in 2009 the turbine market swelled 15% despite the economic slump, according to the American Wind Energy Association (AWEA). The market boom, buoyed by growing interest in alternative energy, is a direct result of federal tax credits worth 30% of wind-harvesting costs.

More reliable and durable equipment also has helped. "The technology has really moved forward," says Sterling Condit, a Kansas remodeler and turbine dealer. "For example, one of the turbines I sell is practically maintenance-free."

HOW IT WORKS
A wind turbine is essentially a generator with fan blades that catch the breeze and spin the rotor over a coil to create an electric current. The most common are horizontal-axis turbines, which look similar to a pinwheel, and eggbeater-like vertical-axis turbines. Also offered are helix models, which resemble DNA. As the industry picks up speed, new options resembling bike wheels and jet engines mark a competitive quest for the best angle to catch the breeze.

Many horizontal residential models resemble smaller versions of common industrial-sized versions, with a 3-foot to 10-foot blade span, according to Mike Batten, a turbine dealer for Midwest Energy Solutions.

It takes 8-mph winds to kick an average turbine into gear, and about 15 mph for it to generate electricity. Since winds that fast only blow high above ground, for the most effective results a turbine needs to sit on a pole, a house, or a hill, and away from obstacles.

U.S. wind maps show the strongest gusts snaking down the middle states, off the coasts, and near mountains. Air in the Southeast is still, so that region may never see a huge turbine trend.
Average residential models generate from 1 kW to 10 kW, according to the AWEA. A 10-kW unit could completely power an average home in good wind conditions (and potentially have extra power to sell back to the utility company), Batten says, but there are many factors--including turbine location and wind conditions--so it's difficult to give a broad, concrete estimate. A 2-kW model provides just supplemental power, but is a more manageable size. Turbine dealers evaluate each project to determine the best unit for the home buyer's needs and the wind potential of the site.

Most residential systems cost $15,000 to $20,000 installed, say turbine dealers. But the figure is dramatically reduced by federal tax credits, as well as state rebates and tax credits, low-interest loans, and utility incentives.

CHALLENGES
Before a homeowner leaps into wind energy, there are a few considerations: "What are your needs? How can we get there? Where's the application going? What's your elevation? Who's your power company?" says Batten. "You can't just go and stick up a wind turbine."

In addition, codes in most counties dictate how far from the house you can place a turbine, how high it can be, and the amount of acreage required on the lot. While the smallest systems are relatively quiet, 10-foot-long blades create a whooshing noise, a sound manufacturers attempt to silence.

In Kansas, remodeler Condit says some utilities are not eager to embrace wind technology because of the industry's past. "I've actually had a couple of customers discouraged from installing a wind turbine... [Utilities] just say they don't work, they are not reliable, which is not true, but that was true of the early '80s."

But the biggest determining factor is the client, asserts Ferrier. The homeowner has to understand the return on investment and have the resources to pay the up-front costs.

While clients willing to work $15,000 into the budget may be scarce, manufacturers believe the winds are changing direction. "We are looking at the wind industry almost the way we looked at the satellite television industry 20 years ago," says Brian Levine, vice president of business development and marketing at WindTronics. "First those satellite dishes were monstrous … then they got smaller and now people have multiple units on their homes."

Predicts Levine: "I think you are watching the wind industry and the alternative energy industry going mainstream."

Evelyn Royer is Assistant Editor for Building Products. This article originally appeared in the Winter 2011 issue of Building Products.