Making an innovative ‘green’ vessel is more complex than simply switching the fuel in the main engine. That is certainly the case in the hybrid LNG-fuelled purse seiner/pelagic trawler Selvåg Senior
Designed by Norway’s Skipsteknisk and Selvåg AS, Selvåg Senior is an ST-136 LNG design under construction at Turkey’s Cemre Shipyard for Sorheim Holding. Being built for both trawling and purse seining, DNV-class Selvåg Senior will have an overall length of 79.5 m, a beam of 16.2 m and molded depth of 6.9 m, accommodation for 14 and a total volume of just under 2,550 m3 in its 12 refrigerated seawater cargo holds.
Main propulsion will be supplied by a medium-speed, dual-fuel Wärtsilä 8V31DF engine, producing 4,800 kW at 750 rpm and a 352 m3 vertically installed Wärtsilä LNG fuel tank. The main auxiliary genset will be powered by a Cummins QSK60, which will be fitted with IMO Tier III-compliant selective catalytic reduction (SCR) after treatment system.
As is the case in many new Norwegian fishing vessels, Selvåg Senior is designed to minimise energy use. Stored at -140° to -160°C , the LNG fuel must be heated for use by the engines. A cold recovery system will utilise this surplus cold energy to maintain the cold of the RSW in the vessel’s 12 cargo tanks. Meanwhile, surplus heat from the exhaust will be utilised to produce clean electricity. Selvåg Senior will be the first newly built fishing vessel to use this technology.
Additional electricity will be produced with an AMI 560L6L BSFMS 2,500-kW shaft generator. All fish pumps and purse seine and trawl winches are electric. The latter can also generate electrical power when paying out lines. Excess electrical energy will be stored in a large 1-MWh battery pack installed.
The battery pack replaces a diesel-powered auxiliary engine and will be used for peak shaving and to provide a power source at port. At port, the ship will be able to connect to use power from the grid to charge its battery pack. The ship’s electric platform is based on a DC grid solution that provides full flexibility in utilising the main engine throughout its rpm range. All of these power sources, combined with the SCR after treatment of the Cummins QSK60 auxiliary engine, make for a notably green ship.
The complex electrical systems will allow an overall reduction of greenhouse gas emissions by as much as 42% compared to a similar vessel with conventional technology, according to the designer.
Selvåg Senior will be the third LNG-powered fishing vessel worldwide after Libas and Sunny Lady, carrying the DNV notifications: +1A, ICE (C), TMON, E0, Gas Fuelled LNG, Battery (Safety), Fishing Vessel.
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