(Photo: John Miner, Exeter radar station)
Radar operations affected by the turbines
London Free Press, September 27, 2015
Environment Canada can’t block wind farms from being built close enough to throw off its weather radar readings, but it’s won the right to order turbines curtailed during severe weather in Southwestern Ontario, documents obtained by The London Free Press show.
Under a 32-page agreement negotiated with NextEra Canada, Environment Canada can order the Florida-based wind energy giant to reduce wind farm operations in extreme weather that could jeopardize public safety.
Following a call from Environment Canada to its operation centre in Juno Beach, Fla., NextEra has 20 minutes to “feather,” or adjust, turbine blades back in Ontario so they won’t contaminate radar readings, according to the agreement provided to The Free Press under the federal Access to Information Act.
The curtailment can last up to an hour, but can be extended by Environment Canada if dangerous weather conditions — Southwestern Ontario is located in a tornado alley and heavy snow belt — persist.
Ground Zero for industrial turbines in Ontario, with the biggest and largest number of wind farms in the province, Southwestern Ontario has been a hotbed of rural opposition to the highrise-sized installations, which took off after the Liberal government began signing sweetheart deals with energy companies — paying them far more for their electricity than consumers pay — under its Green Energy Act in 2009.
But while much of the opposition to wind farms has come from activists concerned about health, land values and control over where the towers can be built, which the province took away from municipalities, the contamination of weather radar readings by spinning turbine blades — known as “clutter” — is an international concern.
Scientists in United States and Europe have shown that a weather radar signal bounced off a spinning turbine blade can appear to be a rotating cloud or tornado.
The wind farm operations can also distort precipitation estimates.
“It is an issue worldwide,” said Anne-Marie Palfreeman, manager of Environment Canada’s national radar program.
While Southwestern Ontario depends on Environment Canada’s only radar station in the region, in Exeter, north of London, for severe weather alerts, the agency has no jurisdiction over where potentially distorting wind farms are built, Palfreeman said.
“All of the decision-making as far as where wind farms are, is provincial legislation,” she said.
Wind turbines located within five kilometres would be a major concern, since the towers themselves can block the radar signals, she said.
“What we do is ask them, ‘Please, do not build within five kilometres’,” Palfreeman said.
Wind farms built within 50 km show up on the weather radar and can distort what meteorologists see on their screens, she said.
The closest wind farm to the Exeter radar station is NextEra’s Goshen Wind Energy Centre. One of the Goshen turbines is about 14 km west of the weather radar.
When Ontario’s Energy Ministry green-lighted the Goshen project, it made the approval conditional on NextEra reaching an agreement with Environment Canada on measures to reduce the wind farm’s radar interference.
In addition to Goshen, a spokesperson for NextEra said the company has now reached agreements with Environment Canada covering its Bornish, Jericho and Bluewater wind farms, all north of London and within 50 km of the radar station.
“We can assure you that in case of a severe weather event, as determined by Environment Canada, we would abide by the terms in these agreements,” Joselen Bird of NextEra said.
Palfreeman said it’s the weather forecaster’s call if the wind farms need to be curtailed during a severe weather event such as a tornado.
“If they think they need the proponent to feather their blades for us to be able to properly see what is going on, they will ask for it,” she said.
While the Goshen wind farm started operation earlier this year, none of the severe weather events since has required Environment Canada to make the call to NextEra.
Palfreeman said Environment Canada is testing two software packages to see if the distortion caused by wind turbine blades can be reduced.
As part of the agreement between Environment Canada and NextEra, NextEra was required to provide Environment Canada with a performance bond.
The amount of the bond was removed from the copy of the agreement provided to The Free Press by Environment Canada, which cited sections of the Access to Information Act that allow it to withhold financial and commercial information provided by a third party, and contractual details that could interfere with negotiations.