Risk snapshot: Autonomous dredger in Emden

Germany’s far northern tide-affected ports on the North and Baltic Seas are challenged by the constant buildup of sand and silt in port and lock areas. To maintain sufficient port depth, excavation is currently the most common form of maintenance. However, this type of activity is not only very cost-intensive, it is also associated with a significant intervention in aquatic and terrestrial ecosystems.

Project developer, Niedersachsen Ports, came up with the idea of using an autonomous dredger and drew up the plans for its design, delivery and operation at Emden – Germany’s third-largest port, especially for ro-ro ships for the automotive industry. It is situated on the northern banks of the River Ems and consists of two parts: the Outer Port, exposed to the tides, and the tide-independent Inland Port, accessible via two sea locks. Silt around both the tide-exposed port and the locks has made the dredge operation necessary.

The dredger is intended to enable more flexible and environmentally-friendly handling of aquatic sediments by continuously relieving navigable areas of solid silt – promising from both an ecological and an economical perspective.

The “recirculation process,” used for this special form of dredging, ensures that the fluid mud layer is made navigable through dredging by being pumped into the cargo hold of the dredger, enriched with atmospheric oxygen and returned to the harbor basin. By ensuring that the material is suspended in the water and does not settle on the floor, ships can pass through at any time. This method is cheaper and environmentally more gentle, but requires that the recirculation by ship continuously takes place.

The technology’s advantages are obvious: it should reduce personnel, cut costs, increase efficiency through possible multi-shift operations, and is environmentally-friendly. Similar tide-dependent places like certain ports in the US and The Netherlands, which struggle with comparable sediment loads, could benefit from such a solution.

"An autonomous dredger is something new for AGCS," explains Anastasios Leonburg, Risk Engineer at AGCS. "This project is of public interest and also interesting for us as a commercial insurer. In the near future, autonomous or, initially, semi-autonomous ships will be launched which will also need to be insured. In particular, as an insurer, we will benefit from participating in this project in that we will be able to better assess the risks associated with operating an autonomous ship.”