Seattle council poised to approve rooftop wind-energy generators

The latest trend in green energy — windmills — might be appearing on a rooftop in your neighborhood.

The Seattle City Council is poised to approve small wind-energy generators atop town houses, apartments, condos and commercial buildings.

The devices, which are sustainable, clean and can be cheaper than solar panels, have been installed across the country in the past few years: at the Boston airport, a Texas Air Force base, a potato-chip factory in Wisconsin — even on Jay Leno's private garage.

On Monday, the Seattle City Council will consider allowing windmills 15 feet above the height limit on commercial buildings. Later this spring, the council will consider allowing 10-foot-tall windmills on multifamily homes.

"I think we're always looking for ways to ... accommodate clean energy, and this is one way of doing it," said Bryan Stevens, a spokesman for the Seattle Department of Planning and Development. "We wanted to offer the opportunity for folks to experiment with these."

The new federal economic-stimulus package includes a 30 percent tax credit for the purchase of small wind turbines.

But with the new attention has come concerns — about noise, architectural ugliness, even rogue windmill blades dangerously "flipping" off and flying through the air.

Questions also have been raised about whether there's sufficient wind flow in dense areas to make it all worthwhile.

Already, utilities in various parts of the country are harvesting wind energy at huge wind farms built on windy hillsides, including in Eastern Washington. Now companies are manufacturing small wind turbines that can provide power for a residential or commercial building.

The amount of energy generated by the small windmills depends on a variety of factors, including height, design and weather.

"It isn't going to take you off the grid, but it is part of the arsenal that you can put together to reduce your carbon footprint," said Sattie Clark, director of marketing and sustainability for Portland-based Oregon Wind, which will begin next year manufacturing small turbines for residential use.

Thousands of cities, including Denver and San Francisco, have passed zoning rules that allow the structures, according to the American Wind Energy Association.

New York Mayor Michael Bloomberg announced last year he's seeking vendors to put more windmills atop his city's high-rises. Twenty turbines installed last year at an office building at Boston's Logan International Airport are expected to save the airport about $13,000 a year in energy costs.

The machines come in several designs. Some look like traditional windmills, with three propeller-style blades. Others are vertical poles with small circular spinners on top. Still others are shaped like a hollow tube with a double helix inside.

One California-based company, AeroVironment, develops high-design wind turbines that perch on the front edge of a building like miniature helicopter blades.

"It's designed to be attractive," said Steven Gitlin, the company's director of marketing strategy.

AeroVironment sells systems of 10 turbines, installed, for $65,000 to $85,000. Oregon Wind advertises 20-pound residential-sized windmills made of scrap metal for as little as $2,000.

Clay Perry, of the Electric Power Research Institute, said solar panels work better in urban environments than wind turbines because it's hard to find "unfettered wind" in a crowded space. He also raised the possibility that, without regular maintenance, rooftop windmills could toss their blades and endanger people.

"It would be challenging to accommodate in any kind of large scale," he said.

Emily Heffter: 206-464-8246 or eheffter@seattletimes.com