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Wind Turbines

Blown Out of Proportion

Residential tower wind turbines can shave money off your power bills in ideal conditions, but dozens of useless rooftop units have been introduced in the past 2 years as manufacturers dangle big tax breaks as incentive. Minimal standards finally have been introduced, but the industry remains mostly a buyer-beware market.

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It sounds like a “green” dream come true: You walk into your local big-box store, pick out a residential wind turbine, wait for the store’s installers and in a week or so you’re generating your own power. And Uncle Sam will reimburse you for a large chunk of the purchase price.

We can understand how that could interest those who would want an eco-friendly solution to their rising energy bills—who wouldn’t? However, no amount of spin can overcome the fact that for most people, the promise of residential turbines is nothing more than a lot of hot air.

WINDS OF CHANGE. A lot of energy is being put into marketing residential turbines (also known as small-wind turbines). Thirty manufacturers in the United States sell residential wind turbines, 15 of which have appeared in the past 3 years. And the number of residential turbines in operation in 2009 jumped 60 percent from the year before. You even can buy these at select The Home Depot and Lowe’s stores.

Two types of residential turbines are on the market: tower turbines, which have been around, and rooftop turbines, which began to appear on the market 2 years ago. Tower turbines ($3,000 to $20,000) have a 10-to-23-foot rotor diameter (the diameter that is covered by the blades), sit atop a metal tower that’s 80 to 150 feet tall and deliver power to a generator that is wired to your home. Rooftop turbines ($4,000 to $10,000) weigh 200 pounds, have a 6-to-10-foot rotor diameter and can be mounted directly on your roof or to a tower that is on your roof. They are wired directly into your home’s electrical system and connected to the local utility grid.

Both are eligible for an uncapped federal tax credit that allows you to take 30 percent off the purchase and installation costs. Until 2009, this credit had been capped at $4,000. States also have their tax credits for residential turbines of as much as 15 percent. (Database of State Incentives for Renewables & Efficiency, dsireusa.org, will show how much for your state.) So it’s possible for you to get back as much as 45 percent of the installed cost of your turbine.

There’s only one problem: Unless your home fits the narrow specifications that are required for successful wind-energy generation, your turbine could cost you in the end, even with the generous tax incentives. The key to making a turbine work for your home is a real estate agent’s mantra: location, location, location.

STUCK ON THE ROOF. The obvious requirement for a residential turbine is that there needs to be enough wind to power it. Experts with whom we spoke tell us that to fully power the average home, you would need a turbine that is 23 feet in diameter, that is placed 30 feet above the nearest tree or building—and 300 feet from any obstruction that is on the ground—and that is installed where the average annual wind speed is 12 mph. That means that you need a tower turbine and at least 1 acre of land. And if you live in a city, you’re wasting your money on wind power, says Dan Fink, who is an author, consultant and lecturer on residential turbines.

Height requirements and zoning restrictions typically limit tower turbines to rural areas. But so do wind requirements. According to National Climatic Data Center, only 27 of 275 cities meet or exceed a 12-mph annual wind average at rooftop level. In fact, you’ll be lucky to find a rooftop site that has access to a 10-mph average wind, which a rooftop unit needs to generate any power at all, experts tell us, because any rooftop will affect the amount of wind that’s captured.

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