As the offshore wind energy technology is rapidly progressing and because wind turbines at sea have a relatively short life span, repowering scenarios are already being discussed for the oldest wind farms. Ongoing developments result in larger wind turbines and an increased open airspace between turbines. Despite taller towers having larger rotor swept zones and therefore a higher collision risk area compared to smaller-sized turbines, there is increasing evidence that fewer but larger, more power-efficient turbines may have a lower collision rate per installed megawatt. As such, turbine size can offer an opportunity to mitigate seabird fatalities by increasing the clearance below the lower rotor tip. We assessed the seabird collision risk for a hypothetical repowering scenario of the first offshore wind farm zone in Belgian waters with larger turbines and the effect of an additional increase in hub height on that theoretical collision risk. For all species included in this exercise, the estimated collision risk decreased in a repowering scenario with 15 MW turbines (40.4% reduction on average) because of higher clearance between the lower tip of the turbine rotor and the sea level, and the need for a lower number of turbines per km². Increasing the hub height of those 15 MW turbines with 10 m, further decreases the expected number of seabird collisions with another 37% on average. However, terrestrial birds and bats also migrate at sea and the effect of larger turbines on these taxa is less clear. Possibly even more terrestrial birds and bats are at risk of collision compared to the current turbines. So, while larger turbines and increasing the hub height can be beneficial for seabirds, this likely needs to be applied in combination with curtailment strategies, which stop the turbines during heavy migration events, to reduce the impact on other species groups.
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RBINS Staff Publications 2022
The European Union (EU) has committed to an ambitious biodiversity recovery plan in its Biodiversity Strategy for 2030 and the Green Deal. These policies aim to halt biodiversity loss and move towards sustainable development, focusing on restoring degraded habitats, extending the network of protected areas (PAs), and improving the effectiveness of management, governance, and funding. The achievement of conservation goals must be founded on understanding past successes and failures. Here, we summarise the strengths and weaknesses of past EU biodiversity conservation policies and practices and explore future opportunities and challenges. We focus on four main aspects: i) coordination among and within the EU Member States, ii) integration of biodiversity conservation into socio-economic sectors, iii) adequacy and sufficiency of funds, and iv) governance and stakeholder participation.Whilst past conservation efforts have benefitted from common rules across the EU and funding mechanisms, they have failed at operationalizing coordination within and across the Member States, integrating biodiversity conservation into other sectoral policies, adequately funding and effectively enforcing management, and facilitating stakeholder participation in decision-making. Future biodiversity conservation would benefit from an extended and better-managed network of PAs, additional novel funding opportunities, including the private sector, and enhanced co-governance. However, it will be critical to find sustainable solutions to potential conflicts between conservation goals and other socio-economic objectives and to resolve inconsistencies across sectoral policies.
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RBINS Staff Publications 2022
