On October 29, 2020, the German Aerospace Center (DLR) officially launched the NAUTILUS power unit demonstrator at its site in Stuttgart. According to those in charge, the NAUTILUS project is intended to represent a significant step forward in reducing emissions from shipping. NAUTILUS is coordinated by the Institute of Technical Thermodynamics at the DLR and funded by the European Union's Horizon 2020 research and innovation program. The goal is to develop an energy solution for long-distance passenger ships that will cover the energy needs of cruise ships for propulsion and maneuvering as well as for hotel facilities.

Significant reduction in CO2 emissions

The maritime sector is under increasing pressure to decarbonize, and the NAUTILUS Aggregate Demonstrator offers a promising solution. The hybrid SOFC battery system combines highly efficient solid oxide fuel cell (SOFC) technology, which offers significant emission reductions and fuel flexibility, with lithium-ion battery storage to balance the fluctuating energy needs of a ship. Together with technology partners SolydEra, MAN Energy Solutions and RWTH Aachen, DLR has presented the NAUTILUS demonstrator, which has been specifically designed to manage the power supply for fluctuating maritime energy needs while reducing CO2 and non-CO2 emissions. The target values are a reduction of CO2 emissions by more than 40 percent and of non-CO2 emissions by more than 90 percent compared to conventional marine engines. The unit intelligently distributes the energy supply between the SOFC and the battery, ensuring efficient operation during load changes in ship operation, while managing and monitoring the charge and status of the battery.

Initial readings are promising

To validate the NAUTILUS system's potential for reducing emissions, the Stuttgart demonstration site is equipped with an advanced emissions measurement system operated by Lund University. Emissions from the SOFC system are captured in an emission measurement box near the fuel cell stack, then stored and analyzed using a suite of highly accurate on-site instrumentation. These measurements collect data under conditions that simulate typical ship operations. The measurements showed that CO2 emissions were reduced by more than 30 percent, methane emissions and CO are negligible, and particulate emissions are 95 percent lower compared to the reference values set by the International Maritime Organization (IMO) in 2008.

Planned switch to more environmentally friendly fuels

While the current genset demonstrator is powered by natural gas, it can also use other future environmentally friendly fuels, enabling even greater potential for reducing emissions. This fuel-flexible technology makes NAUTILUS a robust solution that can not only meet the International Maritime Organization's (IMO) current 2030 emissions targets, but is also suitable for the post-2030 period to achieve net-zero targets.

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