Exhaust gas cleaning retrofits – Q&A with Manager, Environmental, Aslak Suopanki

With the global sulphur limit coming into force, the year 2020 represents a turning point for the marine industry. How do you see the impact of this change?

The new limit will affect tens of thousands of vessels around the world. The feasibility of installing an SOx scrubber system will increase as the use of low sulphur fuels is not limited to emission control areas (ECAs). The limit will have the most drastic effect on vessels sailing the high seas. We are now handling more and more commercial fleet enquiries concerning tens of vessels at a time instead of individual vessels.

What are the main market drivers for scrubber retrofits?

The main market driver is definitely economic, boiling down to the price difference between heavy fuel oil (HFO) and 0.5% sulphur fuel oil, or marine gas oil (MGO) for operations inside ECAs. For example, a large container ship can save somewhere in the region of USD 40,000 per day by using HFO with a scrubber system, so for a fleet of 25 vessels we’re talking about savings of USD 1 million per day. Ordering a retrofit for several vessels at the same time makes economic sense since it is much cheaper to manufacture several units with the same specification than to manufacture individual units.

What are the main considerations for owners and operators when selecting a scrubber system?

A lot depends on the vessel and customer type, and where the vessels are being operated. However, the most significant considerations seem to be the cost of investment, the cost of operation, the ease of operation, and minimising the effect on a vessel’s operations. Installing a scrubber system can be a challenging project that requires extensive modifications to the funnel. It also takes time because there are several stages involved, from system selection, design and engineering to procurement, dry-docking and finally commissioning. It is important to select a partner who can support you throughout the lifecycle of the project.

What are the most interesting recent developments from a ship owner’s point of view?

In order to minimise – or in the best case even avoid completely – both vessel downtime and the space required on board for the scrubber system, we have introduced a modular installation concept. What makes this concept different is the fact that the entire scrubber system is pre-manufactured and installed sequentially on board as separate modules while the vessel is operating. Because we have the in-house capabilities to perform the necessary installation work underwater, dry-docking can be completely avoided: the modules can simply be loaded on board during port calls. The concept is optimised for large merchant vessels, and especially container ships, as the modules are designed according to the dimensions of the container slots on board. It also makes upgrading – for example, from an open-loop to a hybrid system – much easier.

Could you give an example of a retrofit project that you have completed recently?

One particularly interesting and challenging case was the retrofitting of a large cruise ship. Due to the nature of these ships and their business, they are the most demanding projects. In addition to the very limited space available for the scrubber system, the installation work had to be performed during a voyage with the ship full of passengers. As a result, the retrofitting crew had to be as discreet as possible in order not to disturb them. There were also challenges with the logistics arrangements and storing the installation-related materials on board so that they would not disturb passengers or affect the work of the crew. One less obvious challenge was the fact that even though the vessel had room for thousands of passengers and crew, there was limited accommodation space available for the retrofitting crew.

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