Operational experience with gas fuelled ships
Three shipowners gave their differing operational experiences at the fourth Gas Fuelled Ships conference. First, Kari Granberg of Viking Line returned to the podium to talk specifically about the 'Viking Grace'.
One remarkable fact is that the ship is far below the EEDI target, thanks not only to the use of LNG as fuel but to many other energy saving technologies. These include ABB’s EMMA, and NAPA’s optimisation system. Keeping to the timetable is very important, with speed restrictions in the archipelagos en route meaning that recovering time after a late departure can take a long time to recover. The Aland sea provides one of the few opportunities to speed up, albeit with an adverse effect on fuel consumption.
LNG experience has been totally positive, after a few initial adjustments no disturbances have been noted. Even the untried LNG bunkering has worked well. Engine cleanliness is good, less expensive lubricants can be used and time between oil replacements is longer than with HFO. Exhaust has proved invisible and odourless, with no soot on deck, or soot damage to passengers’ property. Time between overhaul is longer and general maintenance is cheaper. Even potable water consumption is better, thanks to the clean fuel. Five months of all-LNG operation has given a slightly higher consumption than on MDO, but this has been offset by savings due to lower hotel loads and other positives. Further savings will be possible in the future through waste heat recovery and energy storage.
Energy savings of around 60% have been recorded by Grace vs the smaller Isabella.
Fjord 1’s Oscar Bergheim then gave his company’s long
experience with LN- fuelled short-route ferries. This was the first company to
operate gas fuelled passenger ships; 12 are now in service, including one
conversion project. Four key elements add up to the success of the service:
- education, both on shore and on board;
- bunkering, at a dedicated terminal or by truck taking up to 2 hours;
- gas plants, where Mr Bergheim admitted a known small leakage problem, in process of being fixed, but otherwise satisfactory; and
- engines, Rolls-Royce in the larger ferries and Mitsubishi in the smaller ferries, which have proved exceptionally clean running with low maintenance.
Initial thoughts were that with LNG maintenance could be more expensive, but in practice this has turned out to be similar, or slightly less, than with diesel engines.
Ed de Jong of Deen Shipping spoke about the dual-fuel Argonon barge, and two new proposed gas-fuelled bunker barges. He drew comparisons between the 100-years-ago situation when the diesel engine first came in, and now, when the gas engine is gaining ground. His company is in competition with rail and road transport which demands low cost and cleanliness. Scrubber technology is too bulky for inland vessels, so cleaner fuel was the solution. Using natural gas represents a high investment, Argonon uses a conventional Caterpillar diesel engine modified to run on a mix of MDO and gas. After considerable development the ship has been developed as a safe and versatile inland barge. Gas is held in a central tank, and the ship boasts a special lightweight high strength hull structure designed for the high safety requirements for inland vessels. This structure has proved itself in tests and could be scaled up for larger-size seagoing ships. Significant benefits in emissions have been noted, with a saving of 30% in fuel costs, plus the bonus of quiet operation. Argonon is currently used for bunkering HFO in Rotterdam, and is fuelled by road tanker. Experience of this project shows that yards need greater knowledge to ease the construction of gas fuelled vessels, the infrastructure and bunkering need expansion, and finance is proving hard to obtain.
LNG Group, a partnership between Deen Shipping, Veka, and others, has been set up to build LNG fuelled ships and associated infrastructure – including a bunker station in Rotterdam - in the Netherlands, and offer training in LNG.
Following the presentations, the question arose about training for gas fuelled ships operation which seemed to be at variance with IGC and STCW requirements; but it was generally acknowledged that the issues were being addressed at the IMO and in the industry.
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