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Securing the world’s largest offshore windfarm with Giraffe 1X

A major expansion of national energy infrastructure is taking place not only in Europe, but worldwide. It is predicted that offshore wind will be an important source of electricity for Europe, which is heading towards net zero greenhouse gas emissions by 2050. This will require rapid expansion of windfarms, which will have a significant impact on the coastal and offshore environment, on a scale that has not been seen before and therefore important to protect. This can be considered a vital step towards renewable energy capacity to enable transition to a fossil-free society.

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In order to manage and secure the expansion of the large infrastructure commitments a solution must be found for the co-existence of air defence and offshore wind energy. This is essential to ensure that nations around the world can maintain their air defence and early warning capabilities while realising their full offshore wind potential and protecting their nation’s security interest.

Saab and the Danish company Ørsted, known for its global business within renewable energy, tested an offshore radar concept with the 3D AESA radar system Giraffe 1X on the world's largest operating offshore wind farm Hornsea 1, 120 kilometres east of the Yorkshire coast in UK waters during September and October 2021. The tests, which were carried out with satisfactory results, were remotely managed from Sweden and monitored from Denmark by Saab, Ørsted, the Royal Danish Air Force, and the UK's NATS air traffic control. The goal was to mitigate the interference from offshore windfarms on the recognized air and maritime picture as well as to validate the performance in a coastal and offshore environment with parameters such as extreme weather conditions and the highest of wind speeds.

Promising environment for Giraffe 1X

Surveillance and early warning of a nation’s air space is crucial for nations to protect their citizens and critical infrastructure from airborne threats. Long-range air defence radars have been located on land sites for decades, on high ground with unhindered view of the sea to best make threat assessments. Radars such as Giraffe 4A continuously scan immense volumes of airspace every day 24/7, and detect airborne threats and anomalies. Over the last decade, the impact of offshore wind turbines on air defence early warning radars has also been recognised. Offshore wind turbines are large, numerous and they move. Each blade is approximately 70-100 meters long and wind turbine blades might be even longer in the future. This movement of the blades is picked-up by radar and create unwanted clutter, reduction in performance and noise on radar screens. Offshore windfarms are moving further away from shore and the curvature of the earth is still a fact at the same time as the maritime environment and activities change.

Great leverage of small size

A short- or medium-range, high-resolution offshore 3D radar can be a flexible and affordable solution. Giraffe 1X is a combination of operational flexibility, multitasking capabilities and multi-role use for tracking up to 600 airborne and other types of targets simultaneously. The system also offers an Enhance Low, Slow and Small (ELSS)-flying-target detection function. This technology and application enables and complements situational awareness in and around offshore wind farms and even beyond the radar horizon of the ground-based long-range radars.

However, offshore wind farms do not only generate energy, but also increasing demand activities from  vessels, helicopters and unmanned aerial vehicles (UAVs), which are needed for the construction, operation and maintenance of those wind farms. These activities need to be monitored for the safe operation of the offshore infrastructure, not least to support search and rescue services in their missions.

Coexistence of defence and offshore wind energy

The promising cooperation between Saab and Ørsted is pioneering in the field of mutual coexistence. The trial results with Giraffe 1X in the world's largest offshore windfarm will be shared by both partners with relevant government stakeholders in the next phase. This is with the aim of enabling the acceptance of marine areas and specific projects by the authorities. Furthermore, a standardised approach will be developed to guarantee the coexistence of defence and offshore wind energy in the long term. All this contributes to the further development of the knowledge and competence base regarding realistic requirements for offshore wind farms and their situational awareness among state actors, including the armed forces.