On the way to green shipping

Worldwide, approximately 80 percent of freight transport is handled by shipping. The DLR Institute for Maritime Energy Systems researches and develops innovative solutions for reducing their emissions, taking into account the entire energy conversion chain of maritime applications. In the future, green hydrogen is to be the basis for a sustainable alternative where heavy fuel oil is still used today. Preferably, it should enable the familiar convenience of long ranges and fast refueling. However, refueling ships with hydrogen still poses a special challenge to logistics and energy infrastructure.


Photo: DLR

Four questions for Prof. Sören Ehlers, Director of the DLR Institute for Maritime Energy Systems

How do you go about developing the novel hydrogen tanks?

We are looking at suitable energy converters (fuel cells and combustion engines), the electrical grids on board, and the supply and storage of alternative fuels in appropriate tanks. Our main focus is on adaptable tank systems and insulation that can withstand cryogenic conditions, for example for the use of liquid hydrogen.

We then test these energy concepts in our large-scale laboratory and simulate them on a "virtual ship". This is followed by validation of the interaction of the novel energy systems on a real ship at sea. For this purpose, the institute is building large-scale test infrastructures consisting of a test rig in the laboratory and a research vessel.

What is revolutionary about this research vessel in terms of its design? And can it be used anywhere?

What is revolutionary is the possibility of testing different and variable energy system components and fuels under real conditions for the first time in such a way that they can later also be used in merchant ships. The reliability of the systems plays a major role here. To this end, we are researching the influence of ship movements, salty air, humidity, load changes resulting from different maneuvers, and much more. In addition to fuel cells, dual-fuel engines, battery systems and energy networks, we are also investigating numerous issues relating to sensor technology, automation and system monitoring.

When will the first hydrogen-fueled ships be sailing the seas?

Ships can already be refueled with hydrogen today. This can be used to power a fuel cell that generates electrical energy for the propulsion engines - this is basically identical to a hydrogen-powered passenger car. However, the possible ranges are very limited. In addition, frequent and long refueling times would be necessary at currently missing shore-side infrastructures. For larger ships, there is a lack of reliable and especially cost-efficient systems that can withstand the long service lives of ships (around 25 years). This is exactly what we are working on at the DLR Institute for Maritime Energy Systems.