A focus on climate-neutral energy sources
There are very different options and concepts for making the propulsion systems in shipping more environmentally friendly and climate neutral:
- The use of filter systems
Existing engines can be retrofitted with filter systems (scrubbers for instance). Whilst this does reduce pollutant emissions into the atmosphere, it simply shifts the problem as it results in contaminated waste water and/or filters that must be disposed of in an environmentally friendly manner.
Sailing at lower speeds has been common practice for some time. This reduces fuel consumption, which reduces costs in times of high fuel prices and, at the same time, reduces emissions. This is a good approach, but is not the solution.
The impact of switching from heavy fuel oil to low-sulphur marine diesel or, even better, to liquefied natural gas (LNG) is considerable. The disadvantage is that it still involves the burning of fossil fuels, and generates CO2 emissions accordingly.
The shipping company Scandlines is equipping ferries with state-of-the-art rotor sails; another shipping company is using battery modules on inland vessels; a solar catamaran for 300 guests will sail on Lake Constance from summer 2022 while Finnlines vessels are to employ an innovative new air lubrication system to create bubble layers for reduced friction and hydrodynamic resistance. These are just a few of the ideas and concepts for saving fossil fuels. It is, however, unclear which of these innovations, if any, could represent a realistic long-term solution for cargo shipping.
According to the experts, the future lies in the use of novel, climate-neutral fuels. Various energy sources are considered potential successors to fossil fuels, including synthetic natural gas, hydrogen, 'green' methanol or even ammonia. However, these substances each have their own advantages and disadvantages and require dedicated propulsion engines for the individual fuel. To date, none of the options has succeeded in asserting itself significantly over the others. All are at different stages of research and testing. At the present time, therefore, uncertainty reigns over which concept will prevail.
New fuels require a great deal of effort
And this is precisely what makes things so difficult for the shipping companies at the moment. Because even if a solution were soon to emerge as the most efficient and practical, a mammoth task still awaits all involved parties. Currently, all ports worldwide are designed for refuelling with heavy fuel oil or marine diesel. What would be required, therefore, would be the construction of another complete tank infrastructure in parallel to the existing one. In order for new ships with climate-friendly engines to remain flexible, there would need to be sufficient availability of the new fuel everywhere. This would mean that transport capacities, storage facilities, refuelling facilities and port logistics would have to be created from scratch in a multitude of ports worldwide – a gargantuan challenge for port operators!