BC Ferries’ new hybrid-electric class is ready to be converted to fully electric
BC Ferries’ new Island-class ships are ready to be converted from hybrid-electric vessels to fully electric ferries in the future.
Damen Shipyards Group is building all six vessels at its Galati shipyard in Romania. The vessels are designed to carry 47 vehicles and up to 450 passengers and crew.
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.
Damen product director ferries Henk Grunstra tells Passenger Ship Technology about the planned move from hybrid electric to full electric and the impact on the design and construction of the ferries. “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 to look long term, 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 make vessels full electric in future.
“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.”
From hybrid to full electric
Mr Grunstra explains 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.”
Damen made the system easy to adapt to different locations. “The software and hardware have been arranged so they can be retuned for a specific operation,” says Mr Grunstra.
One of the major ways the hybrid electric system will be used is for peak shaving, to give the engines the most efficient load possible. “This turned out well,” says Mr Grunstra. He explained a factor behind ensuring the engines were as optimised as possible was to check data from AIS and filter out the way the existing vessels operate. “In general clients do not know all the details of how the vessel is operated and these details are what determines the way the ship is operated. We had to start with the existing situation and see how the vessels are operating. Then we designed the hybrid solution for optimised operation.”
Over the next several months, the crew will be trained to sail the system in as optimised a way as possible and the system may have to be fine-tuned.
The Island-class ferries have two battery rooms, each with 400 kW of batteries. There is room for the battery rooms to be extended to each house 1,000 kW of batteries once the vessels are converted to fully electric.
Mr Grunstra adds “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. “Therefore, we have aimed for the engines to run at their most optimised setting. The goal to make them full electric means the energy saving will be much bigger than now.”
The Orca Energy batteries have been provided by Corvus. Corvus chief commercial officer Halvard Hauso tells Passenger Ship Technology “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 less hours and at optimal loads. When they go full electric, they will save even more maintenance and emissions.”
Other energy efficient features include: the exhaust system reduces NOx emissions through selective catalytic reduction; twin propellers are designed to reduce underwater radiated noise; the vessels are designed to be fully accessible without elevators reducing energy consumption, operating cost and complexity; and the vessels are completely outfitted with LED lighting. In addition, a heat recovery system uses waste thermal energy to heat the vessel, while low friction and a biofouling-resistant hull coating reduces fuel consumption.
Mr Grunstra says “The vessel itself is tailored so the whole design and propulsion system is optimised for operations. An optimised design is very attractive for both a class and a future-proof solution. BC Ferries did a very thorough job, they clearly described what they wanted and made the best solution for that operation.”
An important factor is the Island class of ferries is standardised. Mr Grunstra says “The Island-class ferries are interchangeable and there was an obligation for the shipyard to build them identical. The client said they wanted people not to see anything different apart from name on the side of the ferry, and this is a huge benefit.” This was welcomed by Damen which is renowned for building standard series of vessels.
BC Ferries says standardising its fleet means it will “dramatically improve resiliency in our fleet by allowing us to move vessels around to replace each other during refits, repairs, and unexpected challenges”, as well as providing a more consistent travel experience for our customers and reducing logistical, operational, training and maintenance costs.”
Another strength of the Island-class ferries is greatly reduced noise and vibration levels.
Mr Grunstra explains “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 also focused on optimising the hull for the greatest energy efficiency possible, working within the boundaries of length, beam, draft and weight. The trials show the success here.
Mitsubishi engines were chosen as prime movers. “BC Ferries has fitted many of its ferries with these engines, and they are very pleased with the service and quality of the engine,” says Mr Grunstra.
The rudder propellers came from Schottel while the electric motors were provided by
Leroy Somer. These motors are governed by variable frequency drives made by Vacon.
Schottel is providing its high-efficiency twin propellers to the Island-class fleet.
BC Ferries business development and innovation vice president Captain Jamie Marshall says “We have had positive experiences with Schottel azimuth thrusters in our Salish-class ferries, and opted for the German manufacturer for our Island-class as well. The propulsion system is efficient, quiet and sustainable, and a good fit for our Island-class ferries.”
The main propulsion for each ferry consists of a pair of electric motors each rated 950 kW at 1,700 rpm driving the Schottel STP 340 azimuthing thrusters. Provided with a propeller diameter of 1.85 m, the STP enables a free-sailing speed of 14 knots.
Schottel explains that by sharing the load between two propellers, the risk of cavitation is minimised and tip clearance is increased. Both of these characteristics, in turn, lead to lower underwater radiated noise and vibration levels. This concept also improves the efficiency of the propulsion system and reduces fuel consumption compared to single propellers.
Mr Grunstra spoke about the importance of the contract for the shipyard. “In our portfolio it is what we call ‘medium-sized, medium-complex’, and that is exactly what we want in Romania. The shipyard is very pleased.”
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 comments. “They will run as full-electric all the time unless there are exceptional conditions – it is expected at 90% full electric and 10% hybrid and they are built for full electric propulsion.”
The first of these vessels will be delivered to Canada in Q2 this year.
Snapshot CV: Henk Grunstra (Damen)
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. In these positions he has developed and built numerous types of vessels including pilot boats, patrol vessels, super yachts, high-speed catamarans, ferries, passenger ships and more. These products have been delivered to many clients in many different countries. Damen has recently delivered ferries to Abidjan, Victoria BC, Vancouver, Antwerp, Angola and Copenhagen.