Wind turbines have scary impacts on bats.
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turbines → have → bats
Here's what can be done
Also: Creepy crawlies up close and personal
Welcome to our weekly newsletter where we highlight environmental trends and solutions that are moving us to a more sustainable world.
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that → do → world
Last week, I went to the Electricity Transformation Canada conference in Toronto, and one of the talks that jumped out at me was about protecting bats from wind turbines.
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that → go → turbines
This week:
- Wind turbines have scary impacts on bats.
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turbines → have → bats
Here's what can be done
-
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what → do → ?
The Big Picture: Creepy crawlies up close
- 'Second-hand fashion at its best': Thrift store holds charity fashion show
Wind turbines have scary impacts on bats.
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turbines → hold → bats
Here's what can be done
The eastern red bat is one of three migratory bat species in Canada that have a high risk of mortality from wind turbines.
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that → do → turbines
The one in the photo has a tracking transmitter and antenna attached.
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one → have → transmitter
Wind turbines are considered an environmentally friendly way to generate electricity.
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turbines → consider → electricity
But they are often deadly for bats — a new study this week estimated wind turbines killed 18.7 million bats in the U.S. alone between 1981 and 2024, and the death toll had grown, with the expansion of wind energy, to about 1.5 million bats per year by 2021.
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toll → estimate → 2021
In Canada, the evidence is also scary, especially for our three migratory bat species: A 2023 scientific assessment of the hoary bat, eastern red bat and silver-haired bat found they all face "high risk of mortality at wind energy facilities.
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they → find → facilities
Dana Green, a biologist who co-authored the assessment, said the bats don't seem to be learning to stay away, so the fact that there are fewer dead bats points to a plummeting population — the report recommended they be federally listed as endangered.
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they → co → population
Scientific models suggest "fatalities associated with wind energy facilities" could lead to a 90 per cent population decline over 50 years for the hoary bat and a 22 per cent probability of extinction over 100 years.
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fatalities → suggest → years
Wind turbines don't kill all bats equally.
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turbines → kill → bats
Most species of Canada are small, brown bats that hibernate in Canada and face little risk from turbines (although they've been decimated by a deadly disease called white-nose syndrome).
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they → hibernate → disease
Biologist Dana Green holds a hoary bat during field research in Saskatchewan.
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Green → hold → Saskatchewan
It's the three more colourful migratory species that tend to die from wind turbines during their fall migration to hibernate in the southern U.S. and Mexico.
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that → tend → U.S.
That's when they fly through the wide open migratory pathways where wind turbines are often located.
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turbines → fly → pathways
Green, a postdoctoral researcher at the University of Northern British Columbia, said hoary bats, Canada's largest bat species, seem to be attracted to turbines, although researchers don't know why.
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researchers → say → turbines
So what can be done?
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what → do → ?
The main strategy for protecting bats is "curtailment," which means shutting off wind turbines during certain times if bats are at risk.
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bats → protect → risk
In Ontario, such rules apply to a wind farm if bat mortality is more than 10 bats per turbine per year.
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mortality → apply → year
Normally, wind turbines start operating at wind speeds of three or four metres per second.
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turbines → start → second
But between sunrise and sunset between July 15 and Sept. 30, the rules ban operation if the wind speed is below 5.5 metres per second, since bats tend to fly when it's less windy.
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it → ban → second
Because this "blanket" curtailment reduces the amount of power and revenue a wind farm can generate, more targeted solutions have also been developed.
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solutions → reduce → power
A number of strategies can help protect bats from dying due to wind turbines, such as shutting them off at night during fall migration.
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number → help → migration
"Smart" curtailment uses ultrasonic microphones to detect bats and automatically shut off one or more nearby turbines.
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curtailment → use → turbines
At the Electricity Transformation Canada conference in Toronto last week, Andrew Taylor, a senior ecologist at Stantec Consulting, said smart curtailment can be expensive because it requires a lot of detectors.
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it → say → detectors
Depending on the range of the detectors, the bat could be at risk before the curtailment kicks in — something that also concerns Green.
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that → depend → Green
Taylor said smart curtailment can also make it hard for wind companies to predict how much energy and revenue they could lose due to temporary shutdowns.
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they → say → shutdowns
He presented a solution developed by his company that involves using fewer detectors to monitor bats for a year, relating the number of bats wind and weather patterns, and then using that information to fine-tune when to shut off the turbines.
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that → present → turbines
"We do like to think that we're letting the bats tell us when it's best to curtail," he said.
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he → like → us
Ian Maynard, a research engineer at a Natural Resources Canada lab focused on renewable energy, did a recent analysis of 51 scientific studies on mitigating bat deaths from wind turbines as well as some of his own modelling in Ontario.
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Maynard → focus → Ontario
Maynard said the difference in annual electricity generation and revenues between smart and blanket curtailment is only about two to three per cent, so the higher-tech solution may not always be worth it.
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solution → say → curtailment
Some studies looked at sounds, colours or lighting to deter bats.
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studies → look → bats
Maynard said that's "where a lot of people want to go," but their effectiveness depends on the location and bat species.
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effectiveness → say → location
He found that many studies mitigating bat deaths from turbines weren't large or transparent enough to be reproducible.
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studies → find → turbines
"There needs to be options available," he said.
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he → need → ?
But he added that good scientific evidence is needed before policies can allow them.
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policies → add → them
For now, Green thinks a federal, Canada-wide blanket curtailment policy is needed.
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policy → think → ?
…and 64 more, not listed.
The Aporia
