Mystery solved – Why some wind turbines stand still
When wind turbines stop, bird lives can be saved but windfarm operators might fear significant energy production loss. A new report by BirdLife Europe & Central Asia and STRIX shows how nature and industry can coexist without collisions.
It is a breezy day; the wind tickles the small hair on your skin while you look toward the endlessness of the shallow North Sea. A group of wind turbines are turning in sync with the wind on the horizon. But have you ever noticed the few ones within a wind farm that don’t turn or that seem to go slightly slower than the others?
The reasons can vary, but it could be that this wind farm applies bird curtailment to protect seabirds and migratory land birds from collision. Bird curtailment temporarily stops or slows wind turbines during periods of high collision risk, making it an effective mitigation strategy for onshore and offshore wind farms.
As a response to climate change, offshore wind farms are expanding rapidly, and the voices to reduce possible negative impacts on different habitats are growing louder. Many wind farm operators work with scientists and NGOs to carefully select sites, conduct impact assessments, and even apply measures to reduce noise during construction. Mitigating negative impacts is essential to produce green energy.
Bird curtailment has shown to be a very effective tool to avoid collisions with birds, although some model improvements are still needed. However, it can reduce energy production, due to stopped or slowed-down turbines, and therefore potentially affect the financial viability of wind farms. A new report published by BirdLife Europe & Central Asia and STRIX[1] explores different strategies and monitoring technologies to minimize this potential loss while protecting birds.
Various success stories are featured, such as the Start/Stop project in the Netherlands, which uses a predictive model to identify high-intensity bird migration periods in offshore wind farms in the Dutch part of the North Sea. Avian radar data from offshore areas and environmental and weather data from migration routes are used to develop these prediction models.
With a focus on the North Sea and the Baltic Sea, two regions with extensive offshore wind development, the report advocates for regional cooperation and coordination to ensure bird conservation at a sea basin level.
So, the next time you see wind turbines at sea that are not rotating with the wind, it might be that bird curtailment is implemented to protect our feathery friends.
[1] STRIX is a leading international biodiversity consultancy specializing in the renewable energy sector. Since 2008, they have been at the forefront of technological innovation in ornithological research, being among the first to integrate radar technology within wind farms. STRIX developed BirdTrack ©, a radar-based solution for the automatic detection and tracking of bird and bat targets, enhancing the accuracy and effectiveness of bird monitoring, significantly reducing the risk of avian collisions with turbines.
Cover Picture: shutterstock, lightrain
