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From dangers on the seabed to sustainable wind energy

16. February 2024

Vast amounts of unexploded ordnance corroding on the floor of the North Sea and Baltic, most of it sunk after the Second World War, pose an increasing threat to people and the environment. Rheinmetall and an international working group of specialized maritime companies have developed a solution to this problem in the form of a floating platform, enabling further expansion of offshore wind parks in German waters.

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Challenges posed by unexploded ordnance at sea

Since the end of the Secord World War, vast amounts of unexploded ordnance have lain at the bottom of the North Sea and Baltic. Today these remnants of a long-ago war pose a huge challenge. Recovering and safely destroying this hazardous material is vitally important if we are to minimize the risk to people and the environment

Rising out of the depths, an oval-shaped object covered with barnacles comes into view. It’s an artillery shell from the Second World War, which has rested at the bottom of the Baltic Sea for almost eighty years and is now being hoisted onto a floating platform.

This is happening in the seabed off the Darß peninsula in Mecklenburg-Vorpommern, where in coming years an ultramodern offshore wind park is due to go up. In addition to the Baltic 1 offshore wind park already in operation for the past decade, 103 new wind turbines are to be installed to supply Germany and Scandinavia with sustainable electricity. But before this can begin, unexploded ordnance still needs to be cleared from the seabed. These deadly relics from the Second World War, which pose a significant threat to the environment, navigation and the safety of coastal dwellers, were dropped into the sea after the war ended in 1945, for instance in Lubeck Bay. Prior to installation of additional wind turbines, the extension of cable routes and maintenance of existing systems, the entire area must be scanned and cleared.

Offshore wind parks are giving fresh impetus to Germany’s hoped-for energy revolution.

This also goes for the first commercial offshore wind park in the North Sea, Bard Offshore 1, whose eighty existing wind turbines are undergoing extensive maintenance. Here, too, before the overhaul can start, prior scanning of the seabed for unexploded ordnance is necessary to make sure the wind park can operate safely.

Surface maintenance, e.g., exchanging turbines and servicing rotary blades, is conducted from so-called jack-up vessels. These intelligent ships can push themselves out of the water like mobile oil platforms, enabling work to be carried out in all weathers and rough seas. These intelligent ships can push themselves out of the water like mobile oil platforms, enabling work to be carried out in all weathers and rough seas.

However, the risk of encountering a “souvenir” of the Second World War when lowering the ship’s feet in an unscanned, uncleared part of the seabed is a constant concern. The potential for damage is incalculable, leading in a worst-case scenario to failure of the wind turbine and posing a threat to worker safety.

Operating on its own, Rheinmetall has been conducting a partial survey and clearance of unexploded ordnance in the BARD 1 offshore wind park since May 2023. In the meantime, 14 underwater zones have been comprehensively scanned.

EMMA, short for “EntsorgungsModuleMunitionsAltlasten” (roughly “Disposal Module Unexploded Ordnance”), is a joint project of Rheinmetall Project Solutions GmbH, German Naval Yards and WilNor Governmental Services, whose working group is now carrying out a comprehensive survey and clearance of the seabed at BARD Offshore 1. In the process, onshore and offshore teams work hand in hand.

In summer 2023 Rheinmetall Project Solutions GmbH was able to recommence work at the BARD 1 offshore wind park, examining another 20 areas. The team, headed by Kai-Uwe Mühlbach, Senior Vice President Programs, was particularly concerned about three suspicious objects. A British magnetic mine was suspected based on a prior scan. In such cases, a successful scan is the sole means of achieving confirmation. Rough seas and an approaching storm made the task harder, exacting a heavy toll on people and equipment alike. Finally, though, they could sound the all-clear: during the comprehensive scan, the suspected ordnance turned out to be harmless scrap metal. Looking ahead, offshore wind parks in the North Sea and Baltic are going to be increasingly important. The project team from Rheinmetall is proud to be making an expert contribution in the campaign to produce sustainable energy.

“Thanks to our approach, we’re protecting the underwater world and warding off future hazards”, declares Dr Deniz Akitürk, managing director of Rheinmetall Project Solutions GmbH. “Time is of the essence; the munitions are deteriorating. The impact on the environment is already becoming apparent.”

“EMMA” Unexploded ordnance disposal

In cooperation with WilNor Governmental Services AS of Norway, Rheinmetall aims to ensure safe operation offshore power generation and environmentally friendly disposal of unexploded ordnance at sea. With innovative technology and a highly committed team, they have set themselves the goal of freeing the seas of the dangerous residue of past conflicts. Aiming to destroy several hundred tons of ordnance annually, the project partners have developed a special platform.

Design of the EMMA platform on which the munitions are to be destroyed.

As a prerequisite for building the platform, relevant contracts are to be signed in 2024, enabling operations to start as soon as possible. The need is huge: experts estimate that nearly 1.6 million tonnes of unexploded ammunition and ammunition components lie at the bottom of the North Sea and Baltic.

In the initial expansion phase, the process of transporting recovered ordnance to the platform will be semi-automatic, and in the final expansion phase, fully automated. The logistics necessary for operating the facility are handled from the platform, including support of the recovery robots. This imposing floating complex encompasses an extensive array of rooms with control consoles, storage tanks, sanitary facilities, workshops, rest areas and break rooms.

Because the concept is based on a standard, commercially available North Sea barge (27m x 90 m), most of the components (saws, ovens, lab) can be procured beforehand – a major plus for the project that it is sure to save time.

Following separation onboard, the ordnance is fed into a furnace. In the final expansion phase, this will enable continuous operation of a modular system consisting of thermal disposal conduits. Operating 24 hours a day, 7 days a week, the facility will render unexploded ordnance harmless forever.
But there’s still a lot to do; even with 15 operational barges, it will take decades to clear the seabed of munitions.

Outlook

By 2030, wind parks in the North Sea and Baltic should be producing a total of 30 gigawatts of sustainable electricity, with an ambitious 70 gigawatts projected for 2045. In supporting this endeavour, Rheinmetall is making a significant contribution to achieving the sustainability goals of the EU and Germany.

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