NEWBURY — Janet Fraser had high hopes for substantial savings on her electricity bill when her wind turbine started operating in January.
The 10-kilowatt turbine, built and installed with the help of a grant from the Massachusetts Technology Collaborative, was estimated to produce 11,000 kilowatt hours of power annually.
After operating for eight months on her Newburyport Turnpike property, the turbine has produced only 2,149 kilowatt hours, Fraser said.
"I'm getting only a third of what I expected," she said.
Actually, it's less than that, according to a report prepared by the Technology Collaborative. Based on readings taken during the first six months of the year, the collaborative is projecting Fraser's output at 2,709 kilowatt hours for all of 2008. That's only about 25 percent of the original projection.
The disappointing performance of small wind turbines has caught the attention of Technology Collaborative, which has halted a grant program that many people had used to help buy them.
Indeed the report on a sample of 19 small turbines installed around the state using Technology Collaborative grants, shows that the highest power output is 59 percent, from a 10-kilowatt turbine in the Martha's Vineyard town of Oak Bluffs.
A tower in Scituate is producing only 2 percent of its projected output, and the statewide average is only 27 percent.
Amesbury's Cider Hill Farm installed two wind turbines last year using Technology Collaborative grants: One is producing at 29 percent of expected power, the other at 22 percent, according to the collaborative's report. Cider Hill added a third turbine more recently.
Cider Hill Farm owner Glen Cook said he believed that the formula used to calculate the output of the turbines overstates the average wind speeds at any location.
He said the formula projected each turbine would produce 11,500 kilowatt hours per year, but he was expecting closer to 9,000. Instead, he is finding each turbine is generating 3,000 to 4,000 hours annually.
"I don't for minute regret this," he said. "The price of electricity will continue to increase throughout this decade, and these turbines should perform for another 20 or 30 years with no issues. At some point the economics will look better than they do now, although economics was not the main reason for our decision."
Technology Collaborative spokeswoman Emily Dahl said Cook's analysis of the problem is essentially correct.
She said small wind projects are relatively new to Massachusetts and the collaborative was using data that proved unreliable.
"Manufacturers tend to overstate the capacity of their turbines," she said. "The site maps we were using tended to overstate the wind speeds."
The collaborative's Small Renewables Initiative has stopped accepting applications for new small wind power grants while it reviews the program.
According to the collaborative's Web site, changes in the program would be announced in late summer.
One Newbury resident who is happy with the performance of his wind tower is Fred Thurlow of Marsh Avenue.
Thurlow didn't participate in the Technology Collaborative's grant program. He said the performance of his 1.8-kilowatt turbine varies considerably. He said it produces about 35 kilowatts during the summer months and as much as 150 kilowatts in winter when the wind is stronger.
"A few miles an hour can make a big difference," he said.
He said he and Fraser have compared notes on their respective wind turbines numerous times.
"Maybe her spot isn't windy enough," he said. "I have a pretty windy spot, right on the marsh."
Fred Jackman of Newbury has a turbine that isn't hooked into the regional power grid. It has supplied 100 percent of his electricity for the approximately six months since he installed it.
He said the turbine powers not only lights and appliances but pumps for his well.
"I love my turbine," he said.
Average electric use varies widely, depending on the appliances and size of a home. Most average-sized homes consume between 600 and 1,100 kilowatts per month.
Cider Hill's Cook said he gets three or four calls and e-mails a week from people who are considering installing a wind tower. He said he tells them to be extremely cautious when calculating their expected savings.
"I don't think a turbine is right for every location," he said. "They're very site-specific."