Hornsea Zone Offshore Wind Farm Projects: Comprehensive Environmental Support Across Multiple Phases

Ocean Ecology has been instrumental in supporting Ørsted’s Hornsea Zone Offshore Wind Farm (OWF) projects—some of the largest renewable energy developments globally. Our involvement spans multiple phases and projects, providing critical
environmental surveys, innovative habitat mapping, and long-term monitoring solutions to ensure the sustainable development and operation of these ambitious offshore wind farms.

Key Contributions Across Hornsea OWF Projects

Hornsea One: Geophysical and Benthic Surveys

OEL recently completed an extensive geophysical and benthic survey campaign for Hornsea 1, focusing on infrastructure across the export cable corridors, 26 wind turbine locations, four offshore substations, and 24 inter-array cables. Our work included:

• Multibeam Bathymetry Data Collection to assess seabed features.
• Technical Reporting Outputs: Pre- and post-construction comparisons of scour around key infrastructure to satisfy Marine Licence conditions.

Hornsea Two: Annex I Habitat Mapping and Benthic Investigations

Ørsted contracted OEL to design and execute a large-scale benthic investigation across the entire Hornsea 2 export cable route and array areas. Our contributions included:

• Developing a novel predictive modelling process based on geophysical data and ground-truthing information to map Annex I reef habitats (e.g., Sabellaria and stony reef).
• Conducting targeted seabed imagery surveys using advanced tools, such as the BIIGLE annotation platform, and custom UK-focused classification schemes.
• Advising Ørsted on micro-siting project infrastructure to minimise impacts on sensitive seabed features.

Hornsea Three: Pre-Construction Benthic Surveys

In 2023, OEL conducted pre-construction benthic ecology surveys for Hornsea 3 across the entire project area, including the array and export cable route (ECR). Our focus was to assess potential Annex I reef habitats and establish a baseline to monitor changes to the benthic environment post-construction.

Herring Spawning Monitoring

Ørsted also commissioned OEL to carry out herring spawning monitoring along the Hornsea 2 Export Cable Corridor (ECC). This involved grab sampling to assess sediment type and composition as a proxy for herring spawning ground suitability. The survey was conducted aboard the DSV Curtis Marshall by OEL’s team of ecologists.

Innovative Approaches and Lasting Impact

OEL’s integration of cutting-edge technology, such as predictive habitat mapping and advanced seabed imagery analysis, has enabled Ørsted to optimise project designs, reduce environmental impacts, and meet regulatory requirements. From detailed geophysical and benthic surveys to habitat assessments and post-construction monitoring, Ocean Ecology’s contributions have been pivotal to the success of the Hornsea OWF projects.
By supporting Ørsted across multiple Hornsea Zone developments, OEL continues to demonstrate its expertise in delivering high-quality environmental services for the renewable energy sector