Let’s change the headlines on shipping emissions

International shipping does not often make headlines in the mainstream news. But a meeting of the International Maritime Organization IMO’s MEPC committee last week was being watched by several media outlets. The expectation was that the IMO would set new, additional targets for reduction of greenhouse gas emissions from shipping, a policy campaigned for by some countries but strongly opposed by others. In the end, a middle ground was agreed, with a target of 40–70% improvement in ship efficiency and a 50% reduction in absolute terms of greenhouse gas emissions by 2050.

There are two ways of looking at shipping’s contribution to global greenhouse gas emissions. The first is that shipping is actually very energy efficient: the amount of CO2 emitted per tonne of cargo is much smaller than other forms of transport, such as aviation. But the problem is that the shipping industry is so large that the overall GHG (greenhouse gas) emissions are huge: 3% of the global total in fact.

IMO regulations already in place required new ships to be 30% more efficient than a specified baseline by 2040, but the the new targets announced this week may mean that existing ships also need to meet emission targets.  The good news however, is that appetite for improvement is already there: ship owners are already looking for ways to improve efficiency in both new and existing fleet.

The most obvious way to reduce emissions is to improve ship fuel efficiency. Burning less fuel automatically reduces GHG emissions. But predicting how a ship and engine system will perform under real operating conditions, and the fuel required, is not easy: towing tank tests of a scaled ship cannot look at the full range of wind and wave profiles a ship encounters, nor at the response of the engines to maneuvering. What if instead of relying on tank testing we could predict fuel consumption and vessel energy requirements on a full scale model? What if we could take realistic hull resistance and propeller performance data and look at the ship performance in a virtual environment? We would remove any assumptions or approximations due to scaling, gain a greater understanding of the ship’s performance and quite possibly be able to tune ship systems to perform more efficiently, or even reduce the required engine size.

The good news is that this type of prediction is already possible, using simulation tools. In our recent webinar, Norbert Bulten from Wärtsilä showed how he is using Simcenter STAR-CCM+ and Simcenter Amesim to analyze propulsion systems. As he says, ‘this is the first step toward a true digital twin’. Here at Siemens, we know that co-simulation can do much more: combining 3D and 1D analysis and feeding back information between them gives you the ability to analyze steady sailing, complex maneuvers and real world conditions on a full scale vessel, giving you more information on vessel performance before any physical tests are carried out. We believe that adding co-simulation to your design cycle will save you time and money, and allow you to engineer truly innovative, efficient designs. It is tools like this which will help the marine industry meet and exceed any emissions targets, and help to change the headlines.

Of course, it is easy for us to say that. But we can show you the benefits too. Join us for a live webinar on 24 April when our simulation experts will look at co-simulation in detail and show the predicted fuel savings on a multi-role vessel. And perhaps one day, simulation tools like this will help shipping make the headlines as an environmental leader!

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