A major new stage in the creation of a viable and incentivising LNG fuel supply infrastructure in littoral northern Europe is signalled by the completion of a 7,500m3-capacity LNG bunkering tanker built to the exacting requirements of a UK/German shipowning joint venture, Babcock Schulte Energy (BSE).
The 117-metre Kairos is the first issue of the BSE 50:50 partnership between the Babcock International Group and Bernhard Schulte Shipmanagement, and embodies a novel integration of proven technologies to create an as yet unique vessel imbued with a high degree of operating flexibility and new thinking in cargo emissions control.
As well as ushering-in a substantial advance in LNG bunker supply volume, the ice-class Kairos features a number of innovative developments, including a seawater ballast-free design, and an LNG fuel cargo system characterised by rapid transfer speeds and freedom from atmospheric release of vapour emissions.
Kairos has been assigned to operations in the Baltic region under charter to the joint undertaking known as Blue LNG, in which Hamburg-based Nauticor has a 90% holding, partnered by Lithuanian energy infrastructure provider Klaipedos Nafta with a 10% stake. Nauticor is the Linde Group’s dedicated supplier of LNG fuel for maritime applications.
Sailing from the Ulsan premises of builder Hyundai Mipo Dockyard in South Korea on October 17, the vessel started regular duty after handover to the charterer on December 11 in the port of Klaipeda. Besides assignments centred on the Klaipeda LNG fuelling station, where a 170,000m3 LNG-FSRU (floating storage and regasification unit) is berthed, she will serve various other customers and outlets, including the Linde/AGA terminal at Nynashamn in Sweden.
Capable of performing ship-to-ship bunkering, transhipment and shore discharge, the new supply tanker offers flexibility through direct and sustenance of the range of LNG-fuelled vessels such as ferries, cruise ships and container vessels, and also as a coastal distributor of LNG to industrial consumers ashore.
The capacity vested in the newbuild, outstripping that of LNG bunker tankers to date, is of major consequence. Nauticor’s CEO Mahinde Abeynaike viewed the vessel’s arrival as a milestone event: “With the handover of Kairos, we are securing the supply of LNG as a marine fuel in the Baltic Sea on a large-scale basis. Thanks to the large LNG storage tanks with a pump rate equivalent to more than 30 LNG trucks per hour and our innovative manoeuvring technology, marine customers will be able to benefit from an extremely fast and safe LNG ship-to-ship supply. From now on, also, large vessels can bunker LNG in the Baltic Sea.”
ADVANTAGE AND AMBITION
Klaipedos Nafta’s CEO Mindaugas Jusius observed that “The main advantage and ambition with the new vessel is to ensure more competitive pricing for the LNG reloading station users. It will not only reduce the cost of the LNG supply chain but will also ensure smooth and reliable service to distribution station users.”
The conceptual design was developed by BMT Titron, a joint undertaking of the BMT Group of the UK and the Alvin Yip-headed companies Titron and API of Hong Kong. BMT Titron proposed a forward bridge, superstructure and machinery configuration, and a gas/diesel-electric power and propulsion system with stern azimuthing thrusters. The improved longitudinal balance offered by the arrangements, bringing the centre of gravity much closer to the centre of buoyancy, obviated the need for seawater ballast and the process of ballast exchange and treatment. Only a limited amount of permanent, passivated fresh water is required for trim purposes.
BMT Titron’s concept was taken forward to the detail design stage by Hyundai Mipo Dockyard, which made dimensional changes and hull form refinements, including the development of a better-performing dead-rise hull shape.
Two independent IMO type C tanks contain the LNG at a minimum temperature of -163°C and maximum vapour pressure of 3.75bar. Ship-to-ship (STS) transfers can be made at rates up to 1,250m3 per hour, through cryogenic, flexible hoses.
The vessel is a showcase for the Fuel Gas Supply Vessel Zero (FGSV0) trademark technology developed in the UK by Babcock as a scalable, emission-free LNG cargo handling and bunkering solution, with cargo boil-off stored as compressed natural gas (CNG) and used as fuel. The environmental benefit and regulatory compliances achieved by eliminating the release of boil-off and flash gas to the atmosphere during normal operations are complemented by the economic gain in capturing and utilising the evaporated gas in the vessel’s Wartsila dual-fuel main machinery for the propulsion and other onboard consumers.
When not loading or offloading cargo, natural boil-off from the tanks is compressed up to CNG pressure (approximately 220 bar) by means of a reciprocating compressor, and then piped to the vessel’s CNG storage tanks. During STS operations, all vaporised LNG generated during fuel transfer and returned from the receiving vessel is retained onboard the Kairos, compressed into the CNG storage, and used as and when required in the power and propulsion plant.
The two CNG cylinders that are an integral part of the FGSV0 system are high-pressure Titan tanks supplied by the Hexagon Composites subsidiary Hexagon Lincoln. “By compressing the boil-off and flash gas and supplying it as fuel to the ship’s engines, our clients will save distillate fuel costs and at the same time reduce the vessel’s emissions of SOx and particulate matter (PM),” confirmed Andrew Scott, general manager at Babcock LGE Process. “In addition, we eliminate fugitive emissions of LNG from the cargo systems, providing a true zero emissions solution.”
The combination of twin azimuthing thrusters aft, two bow thrusters and a RangeGuard targetless proximity system developed by Bernhard Schulte and UK-based Guidance Marine provides the Kairos with a high degree of manoeuvrability, facilitating positioning alongside large ships and ensuring compliance with the DP2 standard. It is claimed that the vessel can rotate 360 degrees within her own length in approximately two minutes. The twin main thruster units employ relatively small diameter propellers, suited to the vessel’s modest laden draught and achieving full immersion in all operational conditions.
The merits of the ‘power station’ concept applied to the Kairos include the possibility of immediate delivery of propulsive power during LNG transfer operations. In emergency scenarios, this confers a rapid sail-away capability in conjunction with the quick release systems adopted for moorings and hoses, using cryogenic PERC high-pressure nitrogen-activated dry break couplings.
The vessel has been designed to bunker LNG to as many different types of ship as possible, not least new-generation ferries and cruiseships powered by dual-fuel plant. This criterion has shaped not only manoeuvring qualities and cargo transfer arrangements and transfer rates, but also fendering provisions.
Mooring arrangements feature fully retractable Yokohama-type fenders and parallel vectoring for maximum safety and minimum hull contact. The operational compass of the hose handling crane on the centre manifold of theKairos ranges from dockside level to 28 metres above the waterline to the transfer bridal on a large or high-sided receiving vessel.
Babcock International ‘s technical know-how as expressed in the LNG bunker supply tanker arises from its acquisition of LGE Process from the Weir Group in January 2013. The transaction augmented the UK company’s engineering services scope with a division specialised in the design, supply and project management of gas processing, handling and storage systems for newbuild gas carriers.
Drawing on the longstanding expertise of Bernhard Schulte Management in the husbandry of gas tankers, reinforced in 2018 through the purchase of Hamburg-based PRONAV, Babcock Schulte Energy anticipates thatKairos will be the first of several such specialised vessels ordered for the small-scale LNG sector.
The newly-completed project received funding support under the terms of the EU’s Connecting Europe Facility, as part of the Blue Baltics LNG infrastructure development initiative. Blue Baltics is focused on industrial solutions for STS and shore-to-ship LNG bunkering as well as reloading in various ports. It is helping to stimulate investments in Lithuania, Sweden and Estonia, towards the establishment of a comprehensive LNG supply chain in the Baltic Sea.