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- The vision of birds has not evolved to perceive large moving structures in their environment, like wind turbines.
- To address birds colliding into wind turbines, painting or patterning turbine blades could improve their visibility.
- The South African Wind Energy Association and conservation group BirdLife SA are encouraging wind farms to trial this method.
- For climate change news and analysis, go to News24 Climate Future.
To deal with bird collisions with wind turbines, industry and bird conservationists are encouraging wind farms to trial the effectiveness of painting or patterning turbine blades to improve their visibility.
Local wind farms are to test the effectiveness of the method, which is part of a tranche of other measures to prevent collisions and improve the environmental impact of wind turbines, explained South African Wind Energy Association (SAWEA) and BirdLife SA.
The organisations have issued a briefing note on the method for wind farm developers, environmental consultants, and other decision-makers for consideration.
This followed a study at a wind farm in Norway – which "showed a significant reduction in annual fatality rates".
The idea is that painting or patterning a wind turbine blade with a high-contrast colour would make it more visible to birds,and they would avoid it.
"The vision of birds, particularly those that hunt from the air, such as birds of prey, has not evolved to perceive large, moving structures in their environment, such as wind turbines," BirdLife SA explained.
But, further research is required to test if the results from the Norway study are applicable to other environments and to determine if it is also effective for different species or groups of species.
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A pilot project has been started at South Africa's Umoya Energy Wind Farm (UEWF) on the West Coast of the Western Cape. The briefing note indicated that there are low fatality rates recorded at the facility. Among these is the endangered Black Harrier.
Other wind farms in South Africa are also considering introducing patterning.
"Marking blades is also now often included as a potential mitigation measure in environmental impact assessments for proposed wind farms in South Africa," the organisations said.
But patterning or painting blades is not just a simple matter.
The wind turbines should not add risk to aircraft safety. The South African Civil Aviation Technical Standards have already put in place standards for the marking of turbines for this reason.
There are also technical considerations to make – for example, the physical weight of the paint may impact the blades and whether turbine suppliers would allow the painting of blades given warranties. It may also be costly for operating wind farms to halt operations to allow for the painting in safe conditions.
"Painting under windy conditions can be challenging and present health and safety risks to workers. Moreover, this can have cost implications for the wind farm if they need to fund and procure the necessary professional services to paint the blades. There will also be operational costs and losses if the turbines need to be stopped for any amount of time when energy production is required," the briefing note highlighted.
For new wind farms, the costs would be negligible if the blades could be painted at a factory beforehand.
The organisations are hopeful that blade patterning will be effective in helping reduce bird collisions and become a standard practice.
