Posters

Abstract

Offshore wind is expanding rapidly in the North Sea, increasing its impact on the local ecological equilibrium [1]. In particular, the rotating wind turbine blades pose a collision risk for resident and migratory seabirds. Commonly used collision risk models often simplify the wind turbine to generic geometry and constant operation, which can bias collision probability estimates [2].  This study presents a Band‑type collision risk model [3] in which the turbine is represented by well‑documented reference wind turbine designs and realistic operating states [4-7]. Instead of using the chord line to approximate the effective collision length, we project the local airfoil section onto the bird’s flight path through the rotor plane. This section‑based treatment, together with more representative geometric and operational inputs, aims to bring the calculation closer to physical reality while remaining compatible with established workflows. We compare the modified model with the standard formulation across multiple reference turbines and operating states, including the idling state, as is the case during curtailment. Results are reported as absolute collision probability per single transit of a bird through the rotor-swept area and as an annualised collision probability per megawatt to enable fair comparison across turbine scales. Additionally, multiple scenarios regarding rotor hub height and clearance height between the sea and the blade tip are investigated. The study demonstrates where turbine representation materially influences risk estimates and clarifies how those differences can propagate into design decisions for offshore wind turbines. The approach improves transparency and reproducibility by relying on open reference wind turbines and documented assumptions. The work is conducted within the ECOAMARE project, which supports strategic policy development for ecologically responsible offshore wind deployment in the North Sea.