Green Mountain Power faced tough questions on Thursday from regulators who are considering fines against the utility for violating sound limits at its Lowell wind project.
GMP told a skeptical Public Service Board that it did not anticipate that snow build-up would aggravate the sound produced by the turbines blades.
The company has acknowledged that last fall and winter it exceeded sound limits five times at its 21 turbine project on the Lowell ridgeline.
The company says the problems were limited and were caused by “abnormal conditions” that allowed snow to build up on the turbine blades. GMP witness Joshua Castonguay, who manages operations at Lowell, testified that neither the utility nor the turbine manufacturer thought that snow would exacerbate the turbine sound.
Board member David Coen seemed incredulous at that response.
“You stated that the violation occurred because of abnormal conditions, is that what you said earlier? And those abnormal conditions were snow?” Coen asked.
“No, snowing is not,” Castonguay replied. “That’s pretty normal, I’d say.”
“So what was abnormal here?” Coen asked again.
“The actual snow accumulation on the turbine blades themselves,” Castonguay said.
The exchange was one of several in which Green Mountain Power was grilled about the violations and the monitoring system it’s put in place to detect problems.
PSB lawyer John Cotter cross examined GMP’s sound consultant Kenneth Kaliski about how his audio testing worked. Under questioning, Kaliski confirmed that the results are not counted when rain, high wind or even bird song interferes with the microphones. Kaliski acknowledged that during this year’s rainy spring, results could not be used in nine out of 14 monitoring periods. Attorney Cotter pressed the point.
“I mean, in a perfect world, wouldn’t you prefer to have a monitoring period where you didn’t have to exclude time periods in nine out of 14 days?” he asked.
The Public Service Department, the agency that represents ratepayers, said GMP should be fined up to $50,000. The department also wants the board to order GMP to conduct continuous audio monitoring of the Lowell turbines. But Kaliski, the utility’s sound consultant, said that would be expensive.
“The telemetry would be extremely difficult so it would require visiting the site to collect the data,” he said. “My estimates for the first two years of monitoring under that condition would be at the low end, $600,000.”
After the hearing, GMP Vice President Robert Dostis said the company plans to monitor the turbine blades next winter using TV equipment. He said the company obviously realizes it snows in Vermont, engineers just didn’t anticipate what would happen when the snow sticks to the turbine blades.
“The type of snow we’re talking about is heavy, wet snow, very dense with liquid. So that’s what adheres to the turbine,” he said. “The new measuring equipment we have will let us know when we have that type of weather condition. And we can act much quicker.”
Some neighbors of the Lowell project have complained that the sound produced by the turbines disrupts their sleep and causes headaches and other health problems. But the PSB hearing did not fully address the health issues.
The board set Sept. 6th as a deadline for final arguments to be filed in the penalty case.