The Dutch Ministry of Energy has conducted a test to protect migratory birds from offshore wind turbines by temporarily shutting them down. The Borssele and Egmond aan Zee wind farms slowed to minimum speed for four hours one night, allowing migrating birds to fly past with less risk. The ministry plans to make such shutdowns more frequent and added the grid operators can compensate for the shutdowns by using other power generation capacity.
The shutdown test was an “international first”. The ministry aims to keep offshore wind farms’ impact on nature as small as possible and minimize disruption to bird migration. Dutch media reported that the owners of the wind farms will not be compensated for lost income.
The impact of offshore wind farms on seabirds is challenging to assess because the turbines make dead seabirds disappear into the water. Nonetheless, researchers at UC Santa Cruz are developing population models to estimate the impact on seabird populations and migratory movements, as well as predictive models for bird strike risk. Donald Croll, a professor of ecology and evolutionary biology at UC Santa Cruz, stated that they have been studying these species for years and have developed a fair amount of information about what species are present and where they are going.
Vattenfall, an operator, conducted a test off Aberdeen in 2019-2021, taking radar video footage of seabirds near turbines for two years (daylight only). No cases of bird strikes or near misses were recorded with 10,000 recorded interactions during the day. The subject is an active area of engagement with researchers and policymakers working to mitigate the impact of wind energy on bird populations.