February 16, 2009

Homeowners Save With Domestic Wind Turbines

Wind turbine companies are hoping to put smaller turbines in more domestic settings, like on top of homes and garages, the New York Times reported.

Such smaller turbines can be put on rooftops, where the electricity they generate goes straight to the home's circuit box. Homeowners can then watch the needle on their electricity meter turn backward instead of forward, reducing their utility bills while using a renewable resource.

Dave Anderson, co-director of Renewable Devices in Edinburgh, which has partnered with Cascade Engineering in Grand Rapids, Mich. to offer smaller turbines in the United States, said the Swift Wind Turbine is designed to do its job quietly.

He said the Swift Wind Turbine, which has a ring around its blades designed to diffuse noise and limit vibration, never gets any noisier than 35 decibels"”roughly the sound of a quiet conversation.

"The air is steered toward the diffuser ring and dispersed, rather than leaving the blades with a ripping noise," Anderson said.

Michael Ford, manager of the renewable energy business unit at Cascade Engineering, said the turbine costs $10,000 to $12,000 including installation, but when the wind is blowing at 30 miles an hour or more, it will generate 1.5 kilowatts of electrical power. Enough to run fifteen 100-watt light bulbs, he said.

He suggests that prospective customers make careful measurements before they buy, because the turbine requires a fairly strong average wind speed.

"Don't trust your memories about the wind power around your house," he told the New York Times. "People always remember when it's windy."

The Swift Web site even provides a listing of average wind speeds for certain areas.

Ford said the Swift turbine starts contributing electricity when the wind blows at eight miles an hour, increasing output as wind speed increases. The energy output in windy locations should be roughly 2,000-kilowatt hours over a year's time. Therefore, homes using 11,000-kilowatt hours in a year would reduce electricity costs by about 18 percent.

The Swift turbine was customer Kenneth Benefiel's next step towards energy efficiency, after he reduced electricity by a third after buying a more efficient freezer and refrigerator and changing to fluorescent light bulbs.

Benefiel said that in the first five weeks the turbine produced about 60 kilowatt-hours of electricity, enough to power his house for about three days.

"The turbine will conserve energy," he said. "It's making us more self-sufficient, and we're doing our part to cut consumption. You have to think not only about saving money, but about saving resources."

Sander Mertens in Voorburg, the Netherlands, who is a consultant in wind energy and author of "Wind Energy in the Built Environment," said turbines must be placed well above the roof to benefit from wind energy.

The turbine should be at least 15 feet above the roof for a two-story building, for instance. "Put it lower, and you will suffer from small wind speeds and a lot of turbulence," he said.

Mertens website, 'Ingreenious,' offers a spreadsheet that can be downloaded by people who want to do their own calculations for optimum turbine placement.

Ron Stimmel, a specialist in small wind turbines at the trade group American Wind Energy Association, recommends placing the turbine at least 30 feet above anything in a 500-foot radius.

"That way the wind can stretch its legs a bit."

For these taller towers, homeowners should be aware that they might have to deal with local rules prohibiting structures higher than 30 feet or so.

Many prospective buyers will be attracted to the state and federal incentives for owning a turbine. Stimmel said about half the states have some sort of incentive. The New York State Energy Research and Development Authority, for instance, covers up to half of the homeowner's initial cost for a wind turbine.

The Energy Ball is another small wind turbine for residences. It will be sold in the United States by Home Energy Americas, in McKinney, Tex.

Chief executive of the company, Robert Thompson, said he hoped to have the turbines on the market soon. The Energy Ball is shaped like an eggbeater placed sideways, so that its blades turn around a horizontal axis.

Thompson said the V100 model will cost $10,000 to $11,000 installed, and will provide a maximum of 500 watts.


Image 1: Rooftop Mounted Swift Wind Turbine. Courtesy Renewable Devices

Image 2: Energy Ball V100. Courtesy Home Energy Americas


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