Activist continues call for moratorium on wind generators
By John Phair / Today’s Farmer Sept 19 2011
One of Middlesex County’s most vocal opponents to large wind turbines says if a comprehensive health study was completed on the affects of wind turbines it would mean the end of the wind industry in Ontario.
Strathroy-area greenhouse operator Harvey Wrightman has long called on the Ontario government to invoke a moratorium on the construction of wind turbines until a health study can be completed.
“We need a health study,” he says. “It’s not a difficult thing to do and I don’t think it’s too much to ask for.
“But the McGuinty government refuses to do it because they know they will find people out there who are badly affected.”
Wrightman notes that his daughter, Ester Wrightman, heads up a group known as Middlesex Wind Action Group, a loose coalition of citizens concerned with the proliferation of wind turbines in their community and the potential ill health affects those structures may cause.
Harvey Wrightman says and he and his daughter hear from people on an almost daily basis who live near wind farms and who say they’re suffering from maladies such as sleep deprivation, headaches, dizziness, nausea and impairments of cognitive functions.
“People know these complaints are real,” Wrightman says.
“Most people in the rural community don’t disbelieve these claims because you can hardly open a conversation with anyone around here who doesn’t have some direct or indirect contact with somebody who is bothered by the effects of wind generation.”
Wrightman suggests that if the government was to complete a health study on wind turbines it would mark the end of the wind energy business in Ontario.
Wrightman charges that the both the provincial government and the wind energy industry have been remiss in the release of information on wind generation and have maintained a strategy of denial when it comes to suspected health problems.
Because of the technical nature of wind generation the public in general lacks an understanding of the basics that are driving the complaints about the health effects of wind generation, says Wrightman.
“The devil in all this is the technical nature of it, which has worked well for the wind energy industry’s strategy of denial and no release of information,” he says.
He suggests there are two phenomena related to wind generation, particularly in very large generators, that are causing the problems. Neither is well understood by the public. They are wind shear and amplitude modulation.
“These are technical terms but they are fairly simple in nature,” he says.
Winds shear is the difference in wind speeds at the blades nearest the ground level compared with wind speeds at the top of the blade.
During the day when the sun is heating up the earth, the wind speed at the ground level is about the same as the top of the blade, or at about 100 metres, mostly because the heated air rises to upper levels. Consequently, during the day a large wind generator may emit a swishing sound that is barely audible.
But because of the change in temperature at night that changes. At night the winds at the upper levels blow fairly consistently, while at the lower level winds are much more likely to be calm.
“That’s the basis of wind shear,” says Wrightman, adding that wind shear is expressed as a co-efficient and is monitored and recorded by Environment Canada as well as by most airports.
A wind shear factor of 0.4 is about average on summer evenings.
He adds that the blades on a wind turbine are twisted so they’re able to catch the wind to optimize wind power at the upper level.
“But they can’t be suddenly flared or the pitch changed as they come to the lower level, and the blades are therefore pushing wind rather than being driven by it.”
He adds that when the blade passes the tower, the change in air pressure causes a pulsing that can be heard faintly in daylight hours at one to three decibels.
But at night, when the upper pressures are considerably higher — in other words, under wind shear conditions — the pulsing will be in the range of five to 15 decibels.
“At that point it becomes a thump rather than a swish,” Wrightman says, adding that the sound also carries further under wind shear conditions.
“It’s a very distinctive pulsating thump.”
Meanwhile, amplitude modulation refers to the increase in the aerodynamic noise coming from wind turbine blades, and while it’s not well understood, researchers have suggested its severity could be dependent on operating conditions, weather, or even the location of the listener in relation to the turbines and the wind.
Wrightman says there’s no “technical fix” for the wind shear problem and suggests that the only solution is a mandated minimum distance set back for wind turbines of at least 2,000 metres, as opposed to the present requirement of 550 metres.
“They can go ahead and build them, that’s fine, but give me that setback,” says Wrightman, adding that admittedly under those conditions there would be few turbines built within the province.
He says the McGuinty government has steadfastly refused to acknowledge the effects of wind shear and has continued to force his green energy plan on the rural communities of Ontario.