To ensure compliance with the latest standards, six Brittany Ferries’ vessels have been fitted with scrubbers, three of them designed and produced in France.
Sulphur oxides (SOx) in a ship’s exhaust gases can be removed by cleaning systems commonly referred to as ‘scrubbers’. In compliance with Annex VI to the Marpol Convention, French ferry operator Brittany Ferries recently fitted scrubbers to all its vessels. The new regulations limit sulphur emissions to 0.1% in sulphur emission control areas (SECAs), including the Baltic and North Seas and the Channel, and to 0.5% elsewhere by 2020.
(© BRITTANY FERRIES)
“At Brittany Ferries, we’ve been monitoring developments in this area for some time. We first investigated the feasibility of fitting seawater scrubbers to our fleet in 2006,” says Frédéric Pouget, the company’s fleet manager and head of maritime and port operations. Brittany Ferries operates several cross-Channel services and is a strong advocate of the new emission standards.
“We faced quite a challenge from the outset. Our fleet comprises two generations of ships: the Barfleur, Normandie and Cap Finistère are older, while the Armorique, Mont-St-Michel and Pont-Aven are more recent. We needed solutions for all six ships without compromising their operating economics.” In early 2012, parent company Bretagne Angleterre Irlande (BAI) asked STX France of Saint-Nazaire to investigate the project’s technical feasibility. “We know STX France very well and chose to rely on their expertise as both design office and prime contractor for the six retrofits.” It is seriously challenging to fit large items of new equipment to existing vessels of different ages and designs. “In some respects, it’s like a new-build project. We had a broad spectrum of requirements and it took some innovative design work to meet them all.” The BAI and STX teams began by surveying each ship with laser instruments. They then produced computer models and physical mockups of the relevant spaces, complete with fittings and equipment to identify the optimal configuration for each ship. “Because it has such a significant impact on ferry economics, the weight of each item and design change was a major consideration.”
In-line scrubbers were chosen for the three older ships because they are more compact and these ships offered less free space. “Pollution abatement devices by Yara Marine Technologies were duly installed in lieu of the silencers.” These are based on conventional open-loop scrubber technology using seawater’s natural alkalinity. The ship’s exhaust gases are cleaned, or scrubbed, by large quantities of seawater mist that convert the sulphur oxides into non-toxic substances that can then be discharged overboard. “Our three older ships were drydocked at the Astander yard in Spain and fitted with scrubbers during the 2014-15 winter layover.”
The stack of the Normandie(© BRITTANY FERRIES)
More innovative solutions were found for the more recent vessels. “Brittany Ferries is accustomed to keeping its ships for several decades. This meant that we wanted reliable, long-term solutions exceeding the latest regulatory requirements. We consulted our propulsion motor suppliers, but opted instead for bespoke solutions proposed by a French company specialising in flue gas treatment using a technology that could be readily marinised.”
The Pont-Aven (© MICHEL FLOCH)
Brittany Ferries and STX thus worked with LAB, a subsidiary of the France-based CNIM group, specialising in cleaner energy and a wide range of contracting services, including industrial incinerators and flue gas treatment. LAB proposed off-line scrubbers in composite enclosures offering “improved corrosion resistance combined with significant weight savings”. A further advantage is that exhaust gases from several motors (i.e. for propulsion and auxiliary power) can be brought together for treatment by a single scrubber. “This factor proved decisive. Whereas the Normandie had to be fitted with seven scrubbers, the Armorique, with two main propulsion and three auxiliary motors, needed just one.”
The LAB solution uses a wet packed-bed column to significantly increase the contact between exhaust gases and mist, hence treatment efficiency. “Without the increased contact area, it would be impossible to treat such a large volume of gas in such a compact scrubber.” The design also offers two modes of operation; an open-loop mode and a closed-loop one. In the open-loop mode, the mixture of seawater and residue substances leaving the scrubber is discharged overboard; in the closed-loop mode, the mixture is centrifuged in a hydrocyclone to separate water and residue. The water is then treated and the residue stored so it can be offloaded for disposal ashore. “We use either mode, as required.”
The stack of the Armorique (© BRITTANY FERRIES)
(© BRITTANY FERRIES)
(© BRITTANY FERRIES)
The three ships were fitted with scrubbers in 2015 and 2016: the Armorique and the Mont-St-Michel at the Astander yard in Spain and the Pont-Aven at the Remontowa yard in Gdańsk, Poland. “The ships spent more time in drydock than for a normal refit as it took two months to fit the scrubbers to each.” The feedback since the ships have been back in service has been good, so the wager is on the way to being won. “When we began working on this project, we were thinking long term and aiming to exceed the latest regulatory requirements. LAB assured us that their scrubbers would reduce sulphur oxides to less than the required 0.1%; an argument that swayed both us and our partners.”
French environment and energy management agency Ademe supported Brittany Ferries’ efforts to comply with the new regulations by co-financing five of the six conversions under its VTFIA programme. In 2014 and 2016, Ademe launched two calls for projects to reduce the ecological footprints of French ferries below the limits set by international and EU environmental protection agencies. As a result, Ademe provided €6.7 million in subsidies and €13.5m in the form of repayable advances out of Brittany Ferries’ total investment of €70.5m.