Turbine tests: Should you try and catch the wind?

Consumer Reports News: May 18, 2011 04:59 PM

Getting the wind turbine we’re testing up on the roof of Consumer Reports Yonkers, NY headquarters was no easy matter. It took a crane and a three-man crew to muscle the turbine into place and 4,000 pounds of ballast to make sure it stays there. So that got us thinking about how practical it would be for a homeowner to install a wind turbine. The answer, my friend, is blowing in the wind.

The manufacturer of the Honeywell WT6500 claims the wind turbine can provide roughly one-third of an average home’s electricity needs in areas with wind speeds of 10-to-12 miles-per-hour, like in Yonkers. The turbine, which cost $7,000 at Ace Hardware uninstalled, is just one of the rooftop-mounted wind power systems designed for homes. And it qualifies for a 30 percent federal tax credit as well as a net-metering program that lets you sell excess energy back to your local utility

But before you throw caution to the wind, there are some things to consider. Most importantly, do you get enough wind and can your roof support a turbine and the associated stress? Some municipalities also restrict their use so do your homework. Here’s some help.

Windy enough? Not only does your home have to get enough wind but it has to be located in an area without obstacles—other buildings, cell phone towers—to harvest that wind. Can you mount the turbine on the roof or will you need a pole to raise it high enough to clear any obstructions? Wind maps from the National Renewable Energy Laboratory can show you if your location has the 10-mph annual average wind speed recommended to power a grid-connected system. Many wind turbine companies offer free site assessments, and the Department of Energy’s Wind Power America website lists state energy programs that offer free anemometers, which measure wind speed.

Is the roof sound? Roofs aren’t normally rated for the dynamic load that a wind turbine causes, so a local building department may request a structural engineer’s report, says Mick Sagrillo, a wind energy specialist at Wisconsin’s Focus on Energy. You can check with the turbine’s manufacturer to see if you’ll need to reinforce your roof to withstand high-wind conditions. Many manufacturers provide technical documentation that helps.

What do the locals say? Let’s face it, turbines aren’t the most attractive contraptions and, for a variety of reasons, not all municipalities allow them. Contact your local building department to see if any height, size and noise restrictions apply. The Small Wind Toolbox from the American Wind Energy System covers the different types of permits, variances and fees you might need and offers advice on dealing with possible neighbor issues.

Will you benefit? Compare your annual electricity usage and costs to the manufacturer’s power-output claims and payback time. The American Wind Energy Association suggests a list of questions to ask wind-turbine companies. Sagrillo also recommends that you ask for referrals to customers with sites and systems similar to the one you’re considering. The Small Wind Certification Council plans to release ratings of 22 wind turbine systems based on performance and safety criteria developed by the AWEA that will appear on a label on each system. It will list annual energy output, sound levels and power output in 24-mph winds.

Is net metering a net gain? Turbine makers claim you can sell power back to your utility but it’s not as simple as that. When you hook into the grid you have to also install a switch that prevents backfeeding in the event of a power outage. Utilities require this safety feature so that their workers are not endangered. The Database of State Incentives for Renewables and Efficiency lists utilities that buy back excess electricity and also details what special meters and other equipment you’ll need.

Find an installer. If you’re still game, the North American Board of Certified Energy Practitioners is beginning to certify wind system installers. Sagrillo recommends using one either certified or recommended by the manufacturer of your system and to get references from satisfied customers.

We’ll see how satisfied we are over a year of testing the Honeywell and report back in the next few months.

Reporting by Gian Trotta

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