Battery charging arrangements for the world’s first all-electric container feeder are as challenging as the plans to prepare the vessel for autonomous operations
“It may not be unmanned by the end of 2020, but I hope there will be two guys onboard drinking coffee while the vessel sails itself.” That picture of an idyllic workplace comes from Kongsberg Maritime director of technology Ketil Olaf Paulsen. He is responsible for leading the specification of Yara Birkeland, the 120 TEU vessel that will be the first fully electric container feeder when it is delivered in early 2020 and later the world’s first fully autonomous vessel.
Unlike those lucky future crew, the scope and pace of work on Yara Birkeland has been frenetic since the project was announced in mid-2017. Kongsberg, which is leading the project to deliver the design, ship systems and automation for the vessel, demonstrated the concept model in September that year. In May 2018 it agreed a co-operation with cargo-handling specialist Kalmar to build an autonomous cargo-handling system at Porsgrunn, including the world’s first fully automated rail-mounted gantry crane. And in August it awarded Vard the NOK250M (US$29M) contract to build the vessel. Work on the hull began at Vard Braila in Romania in December and the finished ship will be delivered from Vard Brevik.
Contracts for equipment supply have also been flowing rapidly. In November Kongsberg selected Swiss battery provider Leclanché to supply the 7 MWh battery packs for the vessel. They are expected to be the biggest in the world when delivered. Norwegian company Brunvoll was selected to provide propulsion for the vessel, via two PU74 pulling azimuth thrusters of 900 kW and two FU63 tunnel thrusters of 700 kW each.
“The amount of cargo to be delivered is a decisive factor in determining the window that the vessel has for charging”
There are two very distinct design challenges in that description: first and foremost is the powering. Given the innovative nature of the pure battery vessel, redundancy was a key requirement. The batteries will be split into four separate battery rooms, with just one capable of providing the power to return to port in an emergency. The 900 kW azipulls also provide redundancy through twin shaftlines.
Ketil Olaf Paulsen (Kongsberg): Developing systems as regulations emerge has been "like aiming for a moving target"
The provision of shore power has yet to be contracted for. Connection will be possible in at least one of the ports and, although there will be automatic connection, the company has not opted for wireless charging as some other recent projects have. At present, wireless charging is not capable of providing the amount of energy needed, explains Mr Paulsen.
Assessing charging requirements has been a challenge, given the potential for variation in Yara Birkeland’s operating profile. The amount of cargo to be delivered is a decisive factor in determining the window that the vessel has for charging. At full load, with 120 containers – each taking up to three and a half minutes to load or unload – there is a relatively long time. But at 70 containers, time will be more constrained.
The requirement for charging periods of multiple hours may seem high compared to the fast turnarounds achieved by ferries along the Norwegian coast. But the power demand for Yara Birkeland is much higher, and journeys less frequent than those small vessels. While ferries require just a short top-up between journeys, Yara’s vessel could be draining batteries down to around 30% capacity each time.
“Given the innovative nature of the pure battery vessel, redundancy was a key requirement”
Although plans have not been finalised, it is likely that shore connection will be made available at both ports, says Mr Paulsen.
“All our calculations show it is possible to recharge at only the main port. But if the other port has infrastructure for charging as well, if something should happen – like bad weather – they can connect manually and charge there.”
The other aspect of the design challenge is the planned autonomous operation of the vessel. According to Mr Paulsen this is more of a logistical challenge than a technical one. He reports that most of the onboard systems have been confirmed.
“The main challenge there is that we are working with the Norwegian Maritime Administration (NMA) as they are developing rules and requirements. It’s a little bit like aiming for a moving target.”
The process has involved Kongsberg making proposals about the systems it wants to install and NMA investigating whether they are sufficient, as well as setting procedures for verification. Between them, regulator and operator must agree that safety is as good as, or better than, a normally manned ship.
One example of the challenges ahead for Yara Birkeland’s autonomous operation – and for all autonomous vessels – is a collision avoidance strategy that complies with international regulations. Although, says Mr Paulsen, the challenge is “mainly because we know that other ships don’t stick to colregs”.
The use of audio channels is one example. Traditionally ships communicate both with other ships and to shore using mainly audio VHF channels. Kongsberg hopes Yara Birkeland will not have to do this in the long run, as digital communications would be much more effective. But as the project starts, Mr Paulsen accepts that the ship will need to have some form of audio communication system.
“Regulator and operator must agree that safety is as good as, or better than, a normally manned ship”
“There will be digital information sent to the vessel traffic system with route plan, timetables and so on,” he says. “But in some cases, we might also need audible VHF communication. If you encounter a small fishing vessel, for example, you can only communicate over radio.”
As soon as the vessel leaves the shipyard, Yara and Kongsberg will begin testing it for autonomous operation, checking functions one by one – including docking situations, transit, mooring and all functions that will comprise the complete unmanned system.
The local maritime authority will give the vessel an exemption on crewing levels so that only two crew will be needed onboard while these tests are carried out. There will also be a monitoring and remote-control centre capable of taking over the vessel if needed.
In terms of autonomous sailing systems, there should be few surprises. Kongsberg has projects on vessels all along the Norwegian coast that are trialing parts of the technology that will feed into Yara Birkeland, including autonomous docking and transit on vessels of a similar size.
“For sailing from port to port, most systems should have been tested for some time,” says Mr Paulsen. “But then we will have the mooring system, the automatic shore power connection and the interface with the autonomous crane to test. There will be enough challenges.”
Yara Birkeland principal particulars
Length: 79.5 m
Beam: 14.8 m
Draught (full): 6 m
Service speed: 6 knots
Cargo capacity: 120 TEU
Deadweight: 3,200 tonnes
Propulsion: 2 x azimuth pods, 2 x tunnel thrusters
Battery capacity: 7 MWh