“No silver bullet:” Wind farms need site-specific technology to avoid bird and bat turbine collisions

No single technology or approach can do the heavy lifting on preventing bird and bat collisions with wind turbines, and projects need to find site-specific solutions, a new review study has found. 

researchers from Murdoch University’s Harry Butler Institute say that more work is needed on a combined approach that tailors choices to specific species with a range of technology options from radar to acoustic sensors.

“We found technologies designed to prevent bird and bat collisions were under-tested and there is no ‘silver bullet solution’ as such,” said Trish Fleming, a co-author of the paper published in Renewable and Sustainable Energy Reviews. 

“Future wind farm developments will need combined, site-specific strategies to maximise protection for local wildlife.”

That combination choice will depend on which species wind farm owners are obligated to protect. Switching off turbines, also known as curtailment, is the only proven solution to eliminating deaths, the paper found. 

It says data on acoustic deterrents is “inconclusive”, likely reflecting the complex ways that different species communicate and hear sound.

Seasonal curtailment can protect migratory birds, the researchers found, but not much research has been done to validate different approaches.

During the day, radar and camera systems that detect specific species and shut down turbines when they appear are successful for bigger birds.

Turbine maker Goldwind said last year that detection systems radically cut wedge-tail eagle deaths without impacting on revenue.

But this technology is less adept at protecting smaller avians, which are still proving difficult to detect in enough time to turn off a nearby turbine. 

That could be bad news for birds such as the critically endangered orange-bellied parrot, which is just 20cm long and whose migratory flight path to Victoria crosses over Robbins Island, where Acen wants to build a the 929 megawatt (MW) wind project. 

Turbine shutdowns are on the table for the Robbins Island project, but what time period and whether they will be voluntary is yet to be agreed. 

The Murdoch researchers say other techniques for driving off daytime birds have had varying success, from painting a single blade to using sound as a deterrent and visual cues on tower bases.

Other options that might work but need more data to prove are removing food sources around turbines. 

What would be useful for researchers and wind farm owners are a set of standard guidelines to measure what works and what doesn’t. 

The Murdoch researchers suggest recording a range of data from detection range to energy production as a way to test different methods.

“Current technologies, including radar, cameras, acoustic sensors, curtailment and deterrents each have strengths and limitations,” Fleming said in a statement.   

“What we have found is that wind farms need combined, site-specific strategies to be truly effective. In Australia, we still need a lot more data to understand which of these strategies is best suited to our landscapes and wildlife species.”  

For some species, collision mitigation comes from knowing something – anything – about the lives and habits of a species at all. 

In New South Wales, a study using AI and detection equipment has found microbats are more interested in wind turbines than expected. 

Figuring out why will be the next step towards protecting the tiny mammals from being hit by moving blades. 

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