17 Dec 2020 .

DARC: creating harmony between wind energy and bats

What if you could reduce bat fatalities at your wind farm and increase energy yield at the same time?

In 2018, Natural Power brought together a team of bat experts and technology and software engineers to develop a service that would create harmony between wind energy and bats. This service would need to allow our clients to progress projects stuck in development due to bat concerns, reduce the impact of their wind farms on bat populations and increase the energy production and revenue potential.

Detection and Active Response Curtailment – DARC – was born.

Jim Adams, president of North America operations, said: “What we were trying to solve was a complex puzzle across multiple disciplines. It required a deep understanding of bat behavior, but we were also interacting 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.”

Working with the U.S. Department of Energy and the National Renewable Energy Laboratory

Following a proof-of-concept deployment in 2019 and supported by the U.S. 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 Christine Sutter, head of wildlife technology, the support of the DOE and NREL were critical: “Having the DOE critically review our study design and reports ensures our clients will get unbiased results on the DARC system. Access to NREL’s GE 1.5MW wind turbine gave us the ability to test the impact the system far beyond what we would normally be able to do in field deployments.”

Kevin Denman, commercial manager, commented: “Working with Alliant Energy has been great. We were able to use their historic bat activity and wind data to forecast the environmental and financial benefits of DARC. Their confidence in Natural Power gave us the opportunity to gain the necessary endangered species research permit from the U.S. Fish and Wildlife Service for the study under the DOE umbrella. We could not have asked for a better partner on this project.”

The initial results: DARC reduces bat fatalities and energy loss

The operational season is now complete, and the initial study results confirm that DARC will reduce bat fatalities while at the same time reducing the energy loss, compared with blanket curtailment measures. Natural Power’s team is further analysing the data to measure exactly what the benefits of DARC are, and a full report will be issued in 2021 as part of the DOE project. In parallel, suitability studies are ongoing for other wind farms to demonstrate the benefits for both the environment and a project’s financial performance.

To find out more about DARC, please email DARC@naturalpower.com.