Call it wind power for the neighborhood.
Some companies are trying to stake out a middle ground in wind power by making mid-size turbines big enough for a school or big-box retailer to use, but not so big that they require a convoy of trucks to be delivered.
Distributed wind generation with medium-size turbines runs counter to the prevailing trends in the industry. In the past several years, turbines have gotten bigger and bigger to lower the cost of generated electricity. At the opposite extreme, there is rapid growth in sales of the small wind machines designed for a single home.
But mid-size turbine advocates say if the industry can produce an economically attractive product, there's a large potential market.
Optiwind, a company formed two years ago to make mid-size turbines, is designing a machine to work in places with only a fair, or "Class 2," wind resource found in places like its home state of Connecticut. Potential customers could be schools, wastewater treatment plants, or businesses.
"We've designed systems to work in Class 2 areas, which happens to be where most of us live and work," said David Hurwitt, vice president of marketing at Optiwind. "I'm guessing there (are also) a lot of Wal-Marts in more rural areas where there's lots of wind and land."
Placing wind turbines near people--be it in suburbs or even rural farms--is contentious in many communities as people worry about noise, aesthetics, or flickering light. At the same time, the growing interest in cleaner forms of energy for environmental, economic, or political reasons has more people exploring on-site wind power.
Optiwind is developing turbines--slightly less than 200-feet tall--rated at 150 kilowatt or 300 kilowatts, aimed at organizations that have an electricity bill of at least $100,000 a year. Tied to the grid, these turbines cut electricity bills and give the purchaser a predictable cost of electricity, which can be very attractive to an organization like a school, Hurwitt said.
A 150-kilowatt turbine would cover a portion of the electricity needs of an office building or school. By contrast, typical utility-scale turbines are rated at 2,500 kilowatts or 3,000 kilowatts, generating enough electricity at capacity to power hundreds of homes and stores.
Optiwind's turbine eschews the traditional three-blade design and uses a silo-like structure with fans on either side. When the wind hits the structure, it curls over the surface and enters the fans at a higher density to produce more power, Hurwitt explained.
FloDesign Wind Turbine is another company building a mid-size turbine using technology adapted from jet engines. The company, which is funded by venture capital firm Kleiner Perkins Caufield & Byers, is in the process of working on a prototype turbine that also works on the principle of packing more power into available wind.
Like Optiwind's turbine, FloDesign seeks to manipulate air movements so that wind blows faster through turbines to make more power in a smaller space.
"A bunch of other companies are experimenting with different types of wind acceleration. The idea is to improve the concentration of wind, which is the fuel you're working with," Optiwind's Hurwitt said.
Optiwind, which raised a series A round of venture capital from Charles River Ventures last year, plans to build and test its first turbine this year and hopes to launch a commercial product in 2011.
Steel in the ground
The National Renewable Energy Laboratory late last year published a report that found that community-owned wind installations can bring advantages to municipalities and can ease the load on the power grid. But these types of installations--and the machines suited for them--face a number of technical and financial challenges.
When mid-size turbines use the traditional three-blade wind turbine design, they suffer from having a higher capital cost per kilowatt to install and higher maintenance costs, according to the NREL report.
Northern Power, based in Barre, Vt., is managing to sell a mid-size turbine using a three-blade design. Inside, though, it uses a different drivetrain technology than its larger, utility-scale counterparts.
Instead of the typical gear box, its Northwind 100, which is rated at 100 kilowatts, has a direct drivetrain and a generator that uses permanent magnets, which is quieter and more reliable than other designs, said Northern Power CEO John Danner. "Reliability is the name of the game when you are selling to school principals or town mayors--they don't have maintenance departments to keep things up and running," Danner said.
With good wind, high electricity costs, and good incentives, the payback on a 100-kilowatt turbine can be as little as five years, Danner said.
NIMBY or welcome?
Hyannis Country Gardens in Cape Cod went through the rigmarole of erecting a Northern Power wind turbine earlier this year.
One of the store's owners, Diana Duffley, spent almost three years getting the necessary permitting, paying for studies on light flickering and acoustics, and hosting town meetings. After about four months, the turbine produced more electricity than the garden center consumes, with the excess generating about $1,200 worth of electricity.
Neighbors were initially concerned about how the turbine, which has a 120-foot tower, would look and the noise (the turbine is quieter than the garden center's irrigation system). Over time, more people became interested and supportive, she said.
"People are scared of wind. People are trying to get the Cape Wind (offshore farm) project and it's an extremely controversial subject on the Cape. I feel by doing this I can reduce people's fear of wind," Duffley said. "Here, people can see wind power done right."