Offshore installations and submarine cables | Underwater surveillance: The militarization of the Baltic Sea

The Bundeswehr has been authorized to install and operate fixed facilities, such as transmitting and receiving systems, on energy generation facilities in the North and Baltic Seas. This is stated in the area development plan for 2025, which was drawn up by the Federal Maritime and Hydrographic Agency and reported on by WDR and NDR. According to the broadcasters, the reason for this is the observation of Russian ships allegedly used for sabotage of underwater infrastructure.

The plan also requires operators of offshore facilities to install their own radar systems and to transmit the acquired data to the Federal Waterways and Shipping Administration. This authority has not ruled out sharing the data with the German Federal Armed Forces upon request, as reported by WDR and NDR. This is causing concern among operators, as it is unclear who will cover the additional technical and organizational costs.

The Federal Environment Agency had previously called for stronger civil-military cooperation with wind farm operators in a report on "applied research questions for the expansion of offshore wind energy." The agency also pointed out that offshore wind turbines equipped with military sensors could become legitimate military targets in the event of war. Stefan Thimm of the German Offshore Wind Energy Association (Bundesverband Windenergie Offshore eV) also fears this. He therefore sees the protection of the turbines as a responsibility of the state, but the companies are fundamentally willing to cooperate, Thimm told NDR and WDR.

According to the two broadcasters, parallel to the newly mandated civil-military cooperation, the Bundeswehr and the Federal Intelligence Service have been testing another little-known surveillance method for several years: the use of fiber optic cables on the bottom of the Baltic Sea as sensors for military reconnaissance. The electronic pulses emitted by the cables can – similar to radar – help attribute engine or propulsion noises to specific ships. This method is called "distributed acoustic sensing."

The importance of such "intelligent" early warning systems was also highlighted by the EU Commission at the end of March in an "EU Action Plan for Cable Safety." This plan envisions the creation of a national network of various sensors to detect vibrations and unusual activity near cables. This also includes buoys to monitor ships' acoustic signatures.

The resulting data will be compiled into maritime situation reports. According to the Federal Environment Agency, Belgium is a model for this, as it already uses such software for various sensor data, including from offshore platforms. Other countries can be connected via a programming interface.

NATO has also set up a corresponding command center as part of the "Baltic Sentry" task force, which is conducting increased patrols and surveillance flights in the Baltic Sea in response to the sabotage activities attributed to Russia. The focus is on Russia's so-called shadow fleet – older tankers with which the government in Moscow continues to export oil despite sanctions.

The EU Commission goes one step further in its action plan: submarine cables could also be used as secret ports for underwater drones. This includes charging, but also "launching and docking autonomous underwater vehicles," the action plan states. Research in this area is already being funded. To ensure that operators and manufacturers of these systems participate in the new civil-military offensive in the North and Baltic Seas, the EU Commission intends to establish an "industry forum."