Commander Frank Plötner has targeted a container ship on the radar. The approximately 200 meter long freighter comes from the Elbe and is on its way on the North Sea in the direction of the English Channel. He is still about ten miles away from the federal police patrol ship “Bamberg”.

Plötner wants to have the sulfur emissions measured in the exhaust plume coming out of the container ship’s funnel. A drone in the form of a mini helicopter is being prepared for the mission on board the “Bamberg”. It should fly into the exhaust plume and provide the data with the help of a measuring device.

Regulatory fuel

The North Sea is one of the busiest shipping routes in the world. There, as in the Baltic Sea, there is a strict limit for sulfur emissions.

While ship fuels with a maximum sulfur content of 0.5 percent are permitted internationally, a value of 0.1 percent applies in the North and Baltic Seas. “The less sulfur a fuel has, the more expensive it is,” says Carolin Abromeit from the Federal Maritime and Hydrographic Agency (BSH). Therefore, the changeover does not always go smoothly.

Monitoring whether fuel that conforms to the regulations is being used presents the authorities with a challenge: checks on board that are independent of suspicion are time-consuming and expensive. For this reason, the BSH has installed permanent measuring stations in Bremerhaven and on the Kiel Canal.

“It works well,” says Abromeit. If it is determined that the limit value has been exceeded, authorities in the next port of call will take samples from the fuel.

Drone makes authorities more flexible

But what about the tankers, bulk carriers and container giants that sail between the English Channel and Denmark – far from the German coast? This summer, for the first time, the German authorities are using a measuring drone that takes off from a ship. “With the drone we are flexible and can go far,” says Abromeit.

A drone was already used in the Baltic Sea last year. The aircraft took off from the island of Fehmarn during the three-month mission. The result was that almost 98 percent of the ships checked complied with the values, says Carolin Abromeit.

First results

In the North Sea, the results look a little different after three months of drone use: seven violations were found in almost 50 measurements that could be evaluated. The results were made available to the control authorities in all European ports together with the data from the ship in real time, as Abromeit says. If a violation is proven, the shipping companies must expect fines of up to 50,000 euros.

“If the legislation is not controlled, it is ineffective,” says Olaf Trieschmann from the European Maritime Safety Agency (EMSA). For this reason, EMSA has been making the measurement drones available to all European member states upon request for a number of years. “The technology was developed in the military field,” says Trieschmann.

The drone in action

One of the EMSA drones has been in use on the federal police ship “Bamberg” since June. On this day the weather conditions are optimal: the water is flat, the sun is shining, the wind is only moderate.

Although the drone is a good three meters long, it looks a bit lost on the ship’s helipad. Flight professionals commissioned by EMSA are on board so that it can take off immediately. Aleksander Ljudvig has a good view of the drone from the platform in front of the ship’s bridge. He strapped the six-kilo control unit to his stomach. When he gets the green light to take off, the drone quickly gains altitude.

The mini helicopter then flies autonomously to the selected container ship, which is now in sight. Ljudvig’s colleague Roman Nagy monitors the drone camera on a monitor; he can control it with a joystick. The exhaust plume of the freighter is clearly visible on the screen.

When the drone reaches the ship, it flies in and stays there for minutes. “It’s not that easy to find the right spot,” says Nagy. And so only just under half of the measurements in the last three months could be evaluated.

The drone approaches the ship up to a maximum of 100 meters. “The ship’s crew gets that, the drone is loud,” says Commander Plötner. Sometimes calls come to the headquarters because the crew feels threatened by the drone. “Actually, everyone is informed that drone surveillance is possible at any time,” emphasizes Plötner.

Flight expert Nagy is now lucky: he manages to place the drone perfectly in the exhaust plume. The data can also be evaluated quickly. The sulfur content of the container ship is 0.084 percent, i.e. within the permitted range. Carolin Abromeit is not disappointed: “It’s good if you can’t find anything.” A short time later, the aircraft lands back on the police ship. The drone is used up to twice a day, and up to six hours of flight time are available every day.

High CO2 emissions

When the “Bamberg” continues after the mission, a huge yellow cloud can be seen on the horizon. “We see things like that regularly,” says Commander Plötner. The cloud is the result of the emissions on the so-called tanker route – sometimes better and sometimes worse to see depending on the weather. According to a report by EMSA and the European Environment Agency, ships that docked in ports in the EU and the European Economic Area in 2018 caused around 140 million tons of CO2 emissions – despite the applicable limit values.

The drone campaign in the German North Sea will end at the end of August. “We are very satisfied with the progress,” says Abromeit, “and have already submitted an application to the EMSA so that the drone can be used again in the North Sea in 2024.”