Inside a small wind-turbine beta test

In WindTronics’ lab, a protoype of the Honeywell Wind Turbine, which is 6 feet tall and weighs 95 pounds.   (Credit: Martin LaMonica/CNET)

By Martin LaMonica

MUSKEGON, Mich.–Tucked in the back corner of a nondescript office park is an early shoot in the budding green-energy economy–a start-up with big plans for small wind turbines.

Last month, I took a detour from a summer road trip to visit WindTronics and see a prototype of its wind turbine designed for individual homes and commercial buildings. The company’s lab, housed in a nearly empty warehouse, is a glimpse into the fervent experimentation going on among green-tech entrepreneurs and, specifically, in small wind.

With people looking for clean and cheaper forms of energy, sales of small wind turbines are brisk and projected to grow in the coming years. There are now dozens of different small wind turbines available in a dizzying number of designs, although most commercial products are just smaller versions of big turbines–a propeller with three blades.

Despite all the activity, there’s some creeping doubt about the ultimate potential of small wind. A study in Massachusetts and one in the U.K. found that many residential locations don’t have sufficient wind to meet the promised output of small turbines.

WindTronics has designed a turbine that addresses that wind speed issue head on. While most wind turbines start to work when the wind blows at seven or eight miles per hour, its machine–to be sold for $4,500 as the Honeywell Wind Turbine–starts to generate electricity at only two miles per hour. That, say company executives, means small wind can make sense economically in many more locations.

Kilowatts versus kilowatt-hours
Entering WindTronics’ lab, there wasn’t much to see except for a spartan office and conference room. A design drawing of its wheel-like turbine on the wall gave me a clue I was in the right place. After a moment, the turbine’s inventor and chief technical officer, Imad Mahawili, greeted me and brought me into a warehouse.

At the back end of the cavernous room, there was the 6-foot-high turbine, a table with some testing equipment, and a truck trailer that had been converted into a low-cost wind tunnel.

WindTronics has designed its turbine, which is now going through certification testing and will be available later this year, to be mounted on rooftops or onto free-standing poles. The most striking thing about seeing the turbine up close is how big it is. At 6 feet high without the mounting gear, it would be a conspicuous addition on a home’s roofline, although I imagine less so on a pole.

The turbine is built around a wheel with long spokes, each of which has a specially shaped, bendable nylon blade attached to it. Around the rim of this big wheel is a “shroud” that covers the blade edges. This is where WindTronics’ design differs from most other wind machines.

Most turbines have a gear box at the hub of the rotor. As the wind turns the blades, the gear box turns a generator to make electricity.

WindTronics turns things inside out by having the electricity generation happen at the rim of the turbine. Permanent magnets attached to the blade tips spin past stators–essentially wire coils–attached to the shroud to generate a current. Without the resistance of a gear box at the hub, WindTronics says its turbine will spin–and generate electricity–at low wind speeds, which over the course of time will add up to more power than other turbines, company executives argue.

“The reality is because most turbine makers sell to utilities, they have to specify the maximum power,” said Mahawili. “The other companies don’t give details on how many kilowatt-hours a turbine will make, just the plate power (in kilowatts), which doesn’t signify much. We’re really not telling the story as we should.”

WindTronics says its turbine will generate 2,000 kilowatt-hours in a year for a home with a very good–called Class 4–wind resource. That’s between 15 and 20 percent of the annual electricity consumption for the average U.S. home.

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