SACO – Sometimes the long white blades of the windmill recently erected on Saco Island sweep rapidly through the air. Often they hang motionless 100 feet above the ground.
The downtown wind turbine installed by the city of Saco last month has already become a local landmark, with many people noting its activity whenever they pass by Saco Island. As of last week, those who are interested can also keep track of the turbine’s power production on the city’s Web site.
In its first five weeks of operation, the windmill has been sitting still far more often than it has been generating power. Though the supply of wind is highly variable and five weeks is too short a period to judge the effectiveness of a turbine, the first municipally owned, midsized windmill in Maine has not yet reached the production levels expected of it.
Entegrity Wind, the company that sold the Canadian-made turbine to Saco, guaranteed the city it would produce at least 90,0000 kilowatt-hours of electricity per year, worth about $13,500 at market rates. So far, during what is normally a blustery season in Maine, the turbine has generated 1,340 kilowatt hours, or $201 of electricity.
Charles Newcomb with Entegrity said there is a simple explanation for the turbine’s performance: lack of wind.
“It’s been an extremely low-wind month,” he said. “We’ve had one windy day in my book.”
Normally, the knoll on Saco Island where the windmill is located would have average wind speeds of 11 mph this time of year, Newcomb said. Over the last five weeks, he said, the wind speed averaged only 5 mph.
If the $200,000 windmill doesn’t generate the guaranteed quantity of power, the city’s contract with Entegrity requires the company to pay Saco for however much it falls short during the first five years of operation. Both city officials and Newcomb said they hope windy days are ahead and production levels will average out to those predicted according to long-term wind records.
“We’ve got to give it more time,” said Howard Carter, manager of the Saco sewer treatment plant and one of the leaders behind the city’s experiment with wind power.
The windmill’s performance in future months may determine whether more turbines crop up in York County. Saco’s budget for this year includes funds to buy a second turbine from Entegrity that would be erected at the Saco Middle School or the town’s public works garage. Saco Councilor Eric Cote said the city will make this decision based on the results of the Saco Island windmill.
Carter said he receives several calls a week from other communities in Maine and New Hampshire that are considering investing in wind power. Biddeford city officials are also keeping an eye on the Saco windmill, with thoughts of putting up their own turbine.
By its nature, wind is an intermittent source of power. Carter said most turbines spin only 25 percent of the time, and the wind must reach a certain velocity before the motion of the blades generates power. The Saco turbine, for instance, does not begin producing electricity until the wind reaches 8 mph.
At wind speeds between 5 and 8 mph, the turbine sometimes spins without generating power and may actually consume a small amount of electricity. This is why the electrical production tallied on the city’s Web site sometimes goes down.
Though long-term wind averages are consistent over periods of five years or more, Newcomb said the quantity of wind over shorter terms can be highly variable. In any given year, the level of wind can be up to 40 percent higher or lower than the long-term average, he said.
“You do have wind droughts,” he said.
Despite the windmill’s slow start, Saco is not the only community that believes a move toward renewable energy is wise and will pay off in the long term. The Saco windmill has an expected life span of 30 years. The city expects it will cover its own cost in about 12 years and from then on provide free electricity.
Biddeford Mayor Joanne Twomey recently established an energy committee and charged it with, among other things, looking into the feasibility of wind power.
“It energizes me,” Twomey said of the Saco windmill she watches from her corner office in Biddeford City Hall. “I want more than one.”
By Seth Harkness
17 March 2008
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