Brittany Ferries’ new dual-fuel ferry highlights the progress of the E-Flexer, while it has ordered further E-Flexers that will incorporate LNG and batteries
The delivery of Brittany Ferries’ Salamanca LNG dual-fuel ferry highlights the evolution of Stena Roro’s E-Flexer class – with the following vessels for the ferry operator to be LNG and battery hybrid.
Salamanca is the sixth E-Flexer vessel of 12 ordered from China Merchants Jinling (Weihai) shipyard and joins sister ship Galicia which entered service in December 2020 for Brittany Ferries. Both ships are on long-term charter from Stena RoRo.
Stena RoRo chief executive Per Westling tells Passenger Ship Technology, “We placed the order for four plus four ships in 2016. The intention was for Stena Line to have all the ships but there was interest from outside companies as well. We contacted Brittany Ferries as they were in the process of renewing their fleet. We discussed with them and made a long-term charter with them. For the first ship, we used conventional machinery but with scrubbers (Galicia), then soon after that, we started to look at two more ships and they came to us with some items to discuss.”
At that time, Brittany Ferries was developing an LNG-fuelled ship at Flensburger shipyard in Germany. Mr Westling says, “We realised it was a problematic project, and Brittany Ferries wanted to see if we could develop the E-Flexer even further with the use of LNG.”
Stena RoRo newbuilding manager Staffan Stenfelt describes the solutions deployed, “Wärtsilä is providing the fuel gas supply system, with two big C-type tanks below the main deck, and two 12V46DF dual-fuel main engines, plus dual-fuel auxiliary engines. The oil fire boiler is also dual fuelled.
Either a barge or trailer can be used to refuel the vessel, which can be bunkered either side.
Mr Stenfelt says, “This is new technology, so it is a learning process and our internal experts have been involved, alongside Brittany Ferries and the shipyard too, which has built gas-fuelled chemical tankers in its sister shipyard. It has been a very good joint venture.”
Alongside the use of LNG in Salamanca, other fuel-efficient and environmentally friendly features include a long, slender hull and bow design. The underwater hull features a friction-reducing silicon paint coating which further reduces fuel consumption while the propeller and rudder design brings improved manoeuvrability. There are also frequency-controlled fans and cooling water pumps inside the vessel.
Hybrid LNG
Salamanca’s sister vessel will be delivered in 2023. And the French ferry operator has inked a contract with Stena RoRo for two more ships that will go one step further – they will be hybrid LNG and battery powered.
Mr Westling says, “A year ago, Brittany Ferries came to us with even more interesting ideas, and we started to talk about hybrid solutions. This was something we were also looking at in our own development work, but here was a concrete project we could work on and apply the new features.”
Crucial to the development of the LNG-fuelled and hybrid ferries is the relationship between Stena RoRo, the shipyard and naval architect Deltamarin. Mr Stenfelt elaborates, “We looked at this with the shipyard, who we have a very good relationship with, and they were a key element in this. Together with them and Deltamarin, the combination proved to be very successful. We worked and talked together to find solutions.”
Brittany Ferries’ upcoming LNG hybrid vessels will deploy, says Mr Westling, the largest battery packs that have ever been used on a ferry, and will be capable of 11.5 MWh.
And the vessels will be able to adapt as new fuels and technologies mature. Mr Westling says, “In the future, ammonia can be applied or mixed with the LNG, or hydrogen plus LNG could be an option. The engines to be used are gas engines, not just for LNG, so they can work with different fuels.”
The large battery pack will feed into the gearbox of the ship through a power-take-in and has a capacity to enable the ship to make speeds of up to 17.5 knots entirely on batteries. The batteries will also enable zero emissions in port.
The battery supplier has not been chosen yet. Delving into the considerations when it comes to operating the LNG hybrid vessel, Mr Stenfelt emphasises the “crucial” thing is the automation and control of the system, adding, “In terms of how to take in and take out the different consumers, engines and battery pack, we need more automation and control so the crew can easily adapt to the different features.”
He adds, “For example, one route could be powered by full battery and the other by LNG, so it is a complex automation system.”
The ferries’ batteries will be charged by large shoreside plug-in high-voltage connections.
An E-Flexer using batteries and LNG is also being developed for Canadian ferry operator Marine Atlantic. Mr Westling explains, “It is the part of the same development process [as for Brittany Ferries], but will have a slightly different design, designed for their particular requirements but the principle is the same.”
Steel cutting for this ferry is slated to take place in May this year, while the basic design has almost been completed.
Speaking about the basic design of the E-Flexer and adjusting it for different clients, Mr Westling says, “While many things are similar on the E-Flexer, there are high degrees of adjustments for different requirements.
“The key to making them so successful is we allow clients to take part in the design, through a joint working committee. This helps to solve upcoming issues early and make adjustments to the design. Our clients are always taking part, but we are controlling the process from our side.”
He sums up, “It is a heavy investment, and clients need to rely on us and make sure what we do is in line with expectations and the product is exactly as they want, so the working committee is key.”
Enter class 3.0
And after LNG and battery hybrid ferries – the E-Flexer is set to develop further: enter class 3.0, a methanol hybrid combined with batteries design.
Mr Westling says, “We are looking into methanol propulsion, and have set up a joint venture with the world’s second-largest methanol producer, Proman, and are looking at dual fuel methanol/MGO designs, also combined with batteries. We would use grey, blue and eventually green methanol, all reducing the CO2 footprint. Our partner is investing in the production of green methanol. We would therefore be able to offer our clients E-Flexers with the methanol dual-fuel engines as well as the methanol supply itself together with our partner Proman.
“We believe hydrogen and ammonia are extremely difficult fuels to handle, and it will take a significant amount of time [before they are less so] but methanol is readily available. It is also a simpler and less expensive solution than LNG. For example, it does not need the large cryogenic tanks that LNG does.”
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