Renewables consultancy Natural Power has launched a smart curtailment technology to reduce bat collisions with wind turbines.
The Detection and Active Response Curtailment (DARC) system simultaneously reduces bat fatalities and energy losses at wind farms, the company has claimed.
Natural Power brought together a team of bat experts and technology and software engineers to develop the new platform, which it will offer as a service.
Natural Power North America president Jim Adams said: “What we were trying to solve was a complex puzzle across multiple disciplines.
“It required a deep understanding of bat behaviour, as well as interactions with wind farm operational controls.
“We had to design our DARC service to have no mechanical impact on the wind turbines and to maintain the highest level of cybersecurity that our clients expect.”
The system works by installing an acoustic monitor on top of the nacelle that “listens” for bat calls.
When it detects bat activity, it sends a signal to the DARC server where it is processed alongside other SCADA signals from the turbine and meteorological data.
The server then decides whether the turbine should shut down or not. If it forces a shutdown, the blades will slowly come to a stop before lying motionless for 30 minutes.
If more bat activity is detected during this time, the turbines will continue to lie still for 10 minute increments until no activity is detected. The turbines will then start up again.
Following a proof-of-concept deployment in 2019 and supported by the US Department of Energy (DoE) as well as the National Renewable Energy Laboratory (NREL), Natural Power worked with Alliant Energy to install and operate a full system from August to October 2020 at the English Farms wind farm in Iowa.
For a wind farm of similar size with average wind conditions, DARC will “easily increase” the energy production by more than 5000 megawatt-hours a year.
Natural Power wildlife technology head Christine Sutter said: “Having the DoE critically review our study design and reports ensures our clients will receive unbiased results on the DARC system.
“Access to NREL’s GE1.5MW wind turbine gave us the ability to test the impact of the system far beyond what we would normally be able to do in field deployments.
“Furthermore, working with Alliant Energy enabled us to use its historic bat activity and wind data to forecast the environmental and financial benefits of DARC.
“Their confidence in Natural Power also gave us the opportunity to gain the necessary endangered species research permit from the US Fish and Wildlife Service for the study under the DOE umbrella.”