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Tests conducted to reduce turbine noise; Herkimer County site uses quieting software on wind power units

FAIRFIELD – A Spanish utility that is the world’s largest developer of wind power is testing ways to quiet its Herkimer County turbine farm, using a special software that is new to the U.S.

Iberdrola Renewables decided to install the new software, which adjusts blade positioning to reduce noise, after tests at its two-year-old, 37-unit Hardscrabble wind project found turbines were exceeding sound limits imposed by the towns of Fairfield and Norway.

This is the first use in the U.S. of the quieting software, developed by Gamesa, the Spanish company that built the wind turbines, said Bernard Melewski, a lawyer from Altamont who represents the two towns on the issue.

According to a statement from Iberdrola, the noise reduction system is based on “alternative power curves which result in reduced noise. The noise reduction system uses these power curves based on wind speed, wind direction and a time schedule. Once it is configured, it will run automatically.”

During the test, the software will be installed at three of Iberdrola’s 25 turbines in Fairfield. If successful, it would be used there and at 12 turbines in the neighboring town of Norway, said Melewski.

The turbines, at 476 feet, are the tallest in the state so far. The two towns also were the first in the state to require sound testing of turbines after construction, rather than relying solely on pre-construction models to predict sound levels.

The towns had set limits of 50 decibels on the turbines, which is roughly the equivalent of light traffic at a distance of 100 feet or a running refrigerator. Tests at the Hardscabble farm done in the spring and winter of 2011 found noise levels from the turbines were spiking as high as 60 decibels, Melewski said.

That is equivalent to an air conditioner at 20 feet, a sewing machine, large transformer or average street traffic. Even though the nearest homeowners are 1,300 feet from the closest turbine, some complained to the town about the noise, Melewski said.

An Iberdrola statement disputed that the turbines had exceeded the towns’ noise limits. “While our studies do not show turbine sound levels above the permit limit, we do acknowledge we have received complaints from some of the residents and we are working diligently to address the situation,” the statement said.

Iberdrola will report the results of the noise suppression tests to the towns by September, he said. Both towns have the power to suspend or revoke the wind farm permits, and to shut down turbines, if noise problems persist.

The company also owns New York State Electric & Gas and Rochester Gas & Electric.

One of the largest wind power developers in the world, Iberdrola has about 5,400 megawatts of wind turbines in the U.S., or the equivalent of about 10 fossil-fuel fired power plants. The company also has wind farms in Texas, Ohio, North Dakota and California.