Tapping LNG on the fjords
In the first application of its type in marine propulsion, a Norwegian fjord ferry is to use LNG (liquefied natural gas)-fueled engines as the prime movers for a gas-electric powering and drive system. While primarily an environmental initiative, the use of the 'clean' energy source also holds out the prospect of reduced engineering maintenance outgoings over the long-term.
Although Scandinavia remains in the vanguard of 'lean-burn' technology, the plant for the 312 ft. (95-m), doubleended RoRo passenger ferry for operation in the western county of More & Romsdal will be of Japanese origin. It is claimed that the Mitsubishi gas engines, burning LNG derived from North Sea oil production, will produce 90 percent less nitrogen oxide (NOx) emissions relative to a diesel plant of comparable output.
Certain local marine equipment suppliers, witnessing a Japanese success in their own backyard, are skeptical as to the future scope for such installations. Certainly, there is a premium to be paid, and fundamental logistic considerations prevail as regards ensuring LNG bunkers supply.
However, others in the industry believe that Norway's vital coastal and ijord transportation infrastructure, married with the inevitable increase in local controls on atmospheric pollution from ferries and other shipping, will promote further investment along the lines of the More & Romsdal Fylkesbaater project.
As in Sweden and Denmark, in particular, ferries have a very high environmental profile, due to constant operation within communities which have strong views on pollution matters. For the lightly populated Nordic countries, moreover, atmospheric pollution generated by shipping, particularly on a localized basis, is high relative to that produced by other activities.
For sure, the vessel's performance following scheduled delivery at the beginning of next year will be closely followed by the short-sea sector and Nordic ferry industry as a whole. The surge in uptake of selective catalytic reduction (SCR) devices for diesel plant and investment in other measures such as direct water injection (DWI) are indicative of vessel operators' recognition of the need to respond to increasingly stringent local and national controls inspired by environmental issues. Gas engines have intrinsic merits with regard to emissions performance, without the need for secondary measures, and a gaselectric system as specified for the new ferry confers the operational and design flexibility and space-saving benefits otherwise seen with the diesel-electric mode.
The double-ender has been ordered from Langsten Slip & Baatbyggeri, well known for its disposition towards the more challenging newbuild schemes. She has been dimensioned for 96 cars and 300 passengers.Based in each case on a 12-cylinder Mitsubishi Vee engine driving a 650 kW generator, the four genset modules will be arranged on deck, feeding electrical energy to a pair of propulsion motors. The genset modules will be put together at the Spikkestad production plant of Norwegian company Diesel Power. It is anticipated that the vessel's regular service schedule, on a characteristically short fjord crossing, will require just two aggregates to be fired-up, leaving one engine as a standby, and a fourth under maintenance in a rolling program whereby machinery upkeep can be undertaken without prejudicing vessel availability.
