Hornsea 3, UK: Clean switchgear technology for the world's largest offshore wind farm

Marko Graetz, Project Manager – Blue GIS for wind, expresses pride in this achievement: “Delivering the 2000th 8VM1 Blue switchgear from our Berlin factory to Hornsea 3, a project with 197 turbines, underscores the vast scale and potential of offshore wind. It exemplifies how we can harness clean energy even in the harshest environments, contributing to a future with net-zero global warming.”

Like the fierce North Sea winds, the details of Hornsea 3 will blow you away. A 10 billion Euro project, it will comprise up to 231 offshore wind turbines within an area of 696 km². We will deliver 197 units of our 8VM1 Blue GIS™ for that project to our customer Ørsted through Siemens Gamesa. First deliveries have already begun in January 2025, and our 2000th unit was delivered to Newcastle in April 2025 as part of this order. It takes ten days for each unit to pass through the production line; the final delivery will take place by April 2026.

The 8VM1 Blue GIS™ switchgear uses clean air insulation instead of SF6, a potent greenhouse gas with a global warming potential 24,300 times greater than CO₂. This innovation saves approximately 900 tons of CO₂ equivalent per unit compared to traditional SF6-filled bays. Operating at a standard connection voltage of 66 kV, it reduces cable requirements and process losses, cutting costs while ensuring robust, lightweight, and low-maintenance performance tailored for offshore conditions.

First installed in 2017 at Denmark’s Nissum Bredning project, the 8VM1 Blue GIS™ has demonstrated exceptional reliability. Installed at the base of wind turbines, it protects against overloads and short circuits, enabling safe, uninterrupted electricity supply. It operates up to 72.5 kV in both offshore and onshore settings, significantly enhancing wind turbine power output while maintaining zero greenhouse gas emissions from insulation.

Siemens Energy’s Blue portfolio represents a breakthrough in environmentally friendly high-voltage products, combining vacuum switching technology with clean air insulation to eliminate harmful greenhouse gases. This aligns with global efforts to phase out SF6 in power transmission and supports ambitious climate goals.

Hornsea 3 exemplifies how Siemens Energy’s cutting-edge technology and collaboration with partners like Ørsted and Siemens Gamesa are shaping a sustainable energy future - delivering clean, reliable power from the world’s largest offshore wind farm to millions of homes.