Damen Shipyards Group is building all six of BC Ferries’ new Island-class vessels at its Galati shipyard in Romania. The vessels are designed to carry 47 vehicles and up to 450 passengers and crew and will be capable of full-electric propulsion from new.
Two of the ferries were delivered in February 2020: Island Discovery and Island Aurora and are part of BC Ferries’ fleet renewal programme. These will replace 62-year-old North Island Princess and 51-year-old Quadra Queen II. In November, Damen announced it had secured a repeat order from BC Ferries for four additional Island-class ferries.
Discussing the transition from hybrid electric to full electric and the impact of this on the design and construction of the ferries, Damen product director ferries Henk Grunstra says: “When BC Ferries first started looking at using LNG for fuel, it was looking at adding the new Island-class ships to its fleet. It thought LNG for smaller ships was not the most attractive solution, so investigated using hybrid electric or full electric just as the Island-class was to be built.”
He explains the Canadian ferry operator needed a long-term solution, as the vessel will be deployed for the next 40-50 years. Therefore, BC Ferries decided it wanted to run the vessels as fully electric, but needed to start with hybrid-electric power as shore charging facilities are not currently available in the areas the vessels sail.
Mr Grunstra adds: “By starting with hybrid electric, BC Ferries can make the move later relatively easily. The hybrid technology is not a goal, but the first step to making vessels full electric.
“Electric sailing in British Columbia is very attractive as it has a lot of green energy. Therefore, BC Ferries kicked off with the battery pack and hybrid and we have made them ready for future developments so they can be converted to fully electric.”
Mr Grunstra says using hybrid technology makes the design of the vessels “a little more complicated” than full electric, as it requires building an energy power system that makes decisions about when to use batteries, when to use ultra-low sulphur fuel and when to use both. “That was a challenge,” he says “and we had to look at how BC Ferries would use the vessels in different locations. Since this is a class of vessels, the ships will sail in different locations and on different routes and one of the challenges was how to cater to different locations. The software and hardware have been arranged so they can be retuned for a specific operation.”
Peak shaving
The hybrid-electric system will be used, among other ways, for peak shaving, to give the engines the most efficient load possible. Mr Grunstra says checking data from AIS and filtering out the way existing vessels operate was key to ensuring the engines were optimised. “These details determine the way the ship is operated. We had to start with the existing situation and see how the vessels were operating. Then we designed the hybrid solution for optimised operation.”
Over the next several months, the crew will be trained to sail the optimised system and the system may require fine-tuning.
The Island-class ferries have two battery rooms, each with 400 kW of batteries. There is room for these locations to be extended to each house 1,000 kW of batteries once the vessels are converted to fully electric.
Mr Grunstra says: “The electric systems in the ferries can cope with bigger batteries and they have been sized to do this; this means there is space in the switchboards. The only uncertainty is how the vessels will be charged – how the vessel connects to the existing infrastructure needs to be decided. But there are so many options this is not seen as an issue.”
Currently, within the hybrid-electric system, the engines charge the batteries. “We aimed for the engines to run at their most optimised setting,” he says. “The goal to make them fully electric means the energy savings will be much bigger than now.”
The Orca Energy batteries have been provided by Corvus, whose chief commercial officer Halvard Hauso explains: “These batteries are 800 kW which means they are not big enough for zero-emissions operations, but they are prepared for it. We sized the battery to the operational profile before shore power was installed. Once shore power is available, they will have room to expand the battery installation, by adding more to the same system. A hybrid ferry reduces costs and emissions by reducing fuel and at the same time reduces the need for maintenance as the engines are running fewer hours and at optimal loads. When they go full electric, they will save even more maintenance and emissions.”
Another strength of the Island-class ferries is the greatly reduced noise and vibration levels they offer.
Mr Grunstra says: “They are diesel-electric, which reduces noise and vibration and ensures the vessels are very quiet. The propellers are sized generously, so there is not a lot of load on the propulsion system, resulting in a very quiet ship. You can isolate the sources of noise easily on these ships and the electric-driven thrusters also reduce load noise. The propellers have a moderate load, which makes it easier to reduce vibration.”
Damen is also building two road ferries for Ontario that have a similar platform to the BC Ferries’ Island-class, but which will have shore charging included from the start. “They have bigger batteries and are charged at the shore after each run,” Mr Grunstra says. “They will run as full-electric all the time unless there are exceptional conditions.”
Henk Grunstra (Damen): “The hybrid technology is not a goal, but the first step to make vessels fully electric”
Snapshot CV
Damen Shipyards product director ferries Henk Grunstra has a long track record at Damen, starting in 1985 in the engineering department, later being responsible for high-speed and naval craft, luxury yachts and currently ferries
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