A wind farm 126km north of Cape Town is piloting a bird fatality mitigation project in an effort to reduce the number of fatalities of threatened and priority species.
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The Umoya Energy Wind Farm, located about 5km southeast of Hopefield along the R45 in the Saldanha Bay Municipality, is piloting a blade-patterning strategy inspired by a similar project at the Smøla wind-power plant in Norway.
According to Dr Rob Simmons, CEO and co-founder of Birds & Bats Unlimited, 10 turbines should be painted a ‘signal red’ colour, and 10 others should be used as controls (unpainted).
For the project at the Smøla wind-power plant, one of the three blades on a wind turbine was painted black. As per the Daily Maverick, this strategy resulted in 70% fewer bird fatalities at the painted turbines than at the unpainted turbines.
In South Africa, at least 200 bird species have had fatal collisions with wind turbines, and nearly every facility in the country has recorded fatalities of birds from threatened and priority species, says Samantha Ralston-Paton, the birds and renewable energy project manager at Birdlife South Africa.
South African wind farms are required to monitor their impacts on birds and report the data to the Department of Forestry, Fisheries and the Environment, as well as Birdlife SA. ‘We extract the data from the reports and add it to a database of impacts (recording date, species, location, wind farm, survey methods, etc).’
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According to Ralston-Paton, the main problem is the cumulative effect of multiple wind farms on birds and not so much the impact of individual wind farms. She adds that the endangered black harrier might become extinct.
‘The actual number of individuals lost thus far may not seem huge, but by increasing their fatality rate by just three to five birds a year, we will accelerate its time to extinction. The population is already really small — around 1 200 mature individuals.’
Without mitigation, the impact of a wind farm on birds could be ongoing during its 20-year lifespan, she says, adding that mitigation could help some endangered bird species survive in light of South Africa’s plans to build more facilities over the next decade.
Other threatened and priority species that have been reported to collide with wind turbines in South Africa include the Verreaux’s eagle, which is classified as vulnerable; the martial eagle (classified as endangered); the Cape vulture (classified as vulnerable); and the secretary bird (classified as endangered).
‘As wind expands into new areas (such as Mpumalanga) new species will emerge as priorities, but raptors (especially eagles and vultures) tend to be the biggest challenge,’ says Ralston-Paton. ‘The overlap of good wind resources and vultures in the Eastern Cape is also a real challenge as there are socioeconomic benefits to wind energy development. One wind farm reported almost 50 birds killed per turbine per year – mostly swifts (not threatened).’
Furthermore, the South African Bat Assessment Association (Sabaa) says that although bats have sophisticated means of detecting their environment and orienting themselves, a concerning number of bat fatalities have been recorded at wind turbines.
‘This is because large turbine blades move too fast to allow bats to avoid collision. Furthermore, echolocating bats may not echolocate on known routes and so may be surprised by the appearance of new turbines in routine flight paths. Bats may also be killed at wind turbines due to barotrauma (internal injuries due to decompression in the zone of low air pressure near moving blades).’
During the recent Windaba energy conference in Cape Town, Sabaa’s Stephanie Dippenaar said that more than ‘64 species of bats are threatened by wind turbines,’ which could outnumber bird fatalities.
According to the Daily Maverick, wind turbines also have other adverse effects on bats, such as roost disturbances and destruction, the destruction of foraging habitats, the displacement of bats and barriers to migration routes.
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