EDMONTON – Thousands of bats die on southern Alberta wind farms each year, but it’s unclear what effect that is having on the overall population, says Canada’s foremost bat expert, Robert Barclay.
Most of the bats die because their lungs collapse when they run into low air pressure around the tips of the wind turbines – not because they hit the towers or blades.
With wind farms now coming to north-central Alberta – including two new projects east of Edmonton – the impact on bats migrating from northern forests needs further study, says Barclay, a University of Calgary biology professor.
It’s a serious issue, but with no accurate count of the province’s bat population, “it’s hard to say if turbines are killing too many,” said Barclay.
“We know very little about the abundance and distribution of bats in central to northern Alberta.”
Barclay’s research, begun in 2006, uncovered the surprising fact that migrating bats are much more likely than birds to be killed by wind turbines.
Thanks to their sonar bats can detect solid structures, but they cannot detect the changing air pressure that causes bleeding in their lungs. Birds’ lungs are able to withstand the pressure change.
Barclay’s groundbreaking research took place at Transalta’s Summerview wind farm near Pincher Creek in 2005. When the company noticed bat carcasses under the turbines, it asked Barclay to do a study.
Barclay and his team found 20 to 30 dead bats per turbine. But that number was cut almost in half when Transalta decided not run the turbines when the wind was low and bats are most active, he said.
“This work done at Summerview was one of the first cases in North America where this mitigation was adopted, and has since been recommended in many other regions across Canada,” said Mike Peckford, TransAlta’s senior environmentalist.
The province now requires wind farm companies to do a pre-construction study to determine the level of bat activity around a proposed wind farm site, says Lisa Wilkinson, Alberta Environment bat specialist.
The problem is bats often fly in the same windy corridors preferred by wind farms, she added.
Companies can be required to do a count of dead bats near each turbine. If fatalities are too high, they can be required to take steps to reduce them, Wilkinson said.
Those conditions were recently put on northern Alberta’s largest proposed wind farm after the environment department determined there is a “medium to high risk” of bat fatalities.
That project, the Grizzly Bear Creek wind farm by the German energy giant E. ON Climate and Renewables, will have 50 90-metre turbines. Most of the turbines will be east of Vegreville in Minburn County.
The Bull Creek project by BluEarth Renewables was the first to get approval in north-central Alberta, mostly in Wainwright County. It will have 17 turbines at 80 metres high, scaled back from a proposed 46 turbines.
Bats reproduce at a low rate – with only two young each year – “so you have to be careful with these species,” Barclay said.
Wilkinson noted the hazards will multiply as more wind farms are built.
“There’s a cumulative effect if there are more places where bats can be killed, it could take a bigger toll,” Wilkinson.
“We know there are impacts, so we should be cautious. They are a really important part of the eco-system, not just eating mosquitoes but a lot of agricultural pests.”
In Alberta, three types of migrating bats are vulnerable: the silver-haired, eastern red bats, and the hoary bat that hides in trees in the boreal forest.
Bat populations are under heavy pressure; up to 500,000 migrating bats are killed in North American wind farms. As well, hibernating bats are being decimated by a fungal disease that has not yet arrived in Alberta, said Wilkinson.
Gary Marten, spokesperson for E. On, declined to comment other than to say in an email that the company “will fully comply with Alberta Utility Commission regulations and requirements.”
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