By Barbara Kessler
Green Right Now
There’s a new wind whirly-gig on the block. You may not recognize him. Unlike those tall towers with outstretched airplane-style propellers, this new guy has a compact stance, a whole new look. Arms tucked in, he whirs more slowly and congregates with just a few others to power a building at time.
This wind power generator, called a vertical axis wind turbine, can be puzzling. Looking at one, it’s difficult to fathom how it works, though it simply uses a different aerodynamic concept than its propeller cousins, catching up winds that come from different directions bouncing along closer to the ground. The idea has actually been around for at least 2,000 years “but it’s just never been made to work very well,” says Michael Hess, CEO of Mariah Power.
Hess and company say they’re changing that. Using technology and metals (lightweight aluminum and steel) that weren’t available to the ancients who first tried the design, and correcting issues that afflicted more recent incarnations, they’re taking the vertical axis to a new level of efficiency, says Hess, whose Reno, Nevada-based company is one of a handful of vertical wind turbine manufacturers.
“People had made them out of plastic and fiberglass before but that made them wear out, so we use metal (and) we solve the problems of stress and rust…,” he said. “We have to have a very straight pole, for instance, otherwise you have vibrations and movement. It’s straight within 1/16 of an inch over 20 feet.”
The result is Mariah’s “Windspire” – a spare-looking whizzy that stands just 30 feet tall and is only four feet across, making it readily available for single-site use by homes, small businesses and commercial buildings.
It doesn’t produce power at the same rate as those towering edifices on the prairie, because it operates differently and doesn’t ply the faster winds at higher altitudes. But given sufficient ground-level winds, each one can cover about 20 to 30 percent of a home’s energy needs. Specifically, the 1.2 kilowatt Windspire will produce approximately 2000 kilowatt hours (kWh) per year in 12 mph average winds, according to the manufacturer. (The annual consumption of the average American home is about 8,700 kw.)
And it does this for a realistic price. A standard Windspire is $6,500 – or about $4,550 after a federal tax credit for 30 percent of the cost.
Or even less, if your state also offers a clean energy tax incentive that can be used for small wind on top of the federal credit.
There are about 200 Windspires on the ground or set to be installed in residential, commercial and university settings, says Hess. Some, like the one installed at the NC Solar Center of NC State in Raleigh, are demonstration projects.
Others are empowering homes and small facilities in scattered locations across the country.