High oil prices and environmental regulations are driving the increased interest in liquid natural gas (LNG) as an alternative fuel for passenger ships, delegates at the recent Interferry conference in Barcelona were told.

DNV specialist Torill Grimstad Osberg told the conference that switching to natural gas was a good solution for compliance in emissions control areas (ECAs), since LNG is sulphur free and can reduce NOx emissions by up to 90 per cent and carbon dioxide output by up to 20 per cent. Twenty LNG-fuelled ships are already in operation and many more were in the pipeline, including an Incat fast ferry for the Buquebus service between Argentina and Uruguay, she said.On the rules issue, she pointed out that DNV rules covered all design safety aspects and were echoed in international guidelines that are now being developed into an international code. Fire and explosion risks due to gas escapes or mechanical impact could be solved by ventilation and protection barrier systems. On the question of whether it was possible to locate tanks below deck and below accommodation, she stressed: “This is entirely possible with the above safeguards.”

Ingvald Fardal, president and CEO of Norway’s Fjord Line, said his company is planning a dual fuel LNG upgrade within a year of two newbuilds being delivered in late 2012. “Where we operate is the strictest control area in the world and it’s going to get even tighter,” he said. “We know that switching from HFO to distillate is going to cost a lot of money and we are not attracted to the scrubber option, so LNG seems a very good alternative. But where can you fill your ship? There aren’t many facilities in Europe today. And can you fill with passengers on board? This is a crucial consideration and we need confirmation of indications that we will get approval.” 

Raimon Strunck, VP sales at Germany’s Flensburger yard, presented a drive-on tanker trailer solution to meet widespread concerns over lack of LNG bunkering infrastructure and space-consuming onboard storage. Together with gas handling specialist TGE and engine manufacturer MAN, the yard has developed a RoPax design featuring purpose-designed cassette trailers that connect to the fuel system through a special locking device. Strunck suggested a net present value benefit of €10 million over five years compared with the marine gas oil option. He added: “The concept is contract-ready although I can’t disclose details yet.”
Per Stefenson, marine standards advisor and R&D manager at Sweden’s Stena group, highlighted another concern over LNG – that the risk of methane slip could have consequences 20 times worse than carbon dioxide – and suggested that methanol could be the fuel of the future.

He described a retrofit project with Danish company Haldor Topsoe in which methanol is reformed onboard to user-friendly Di-Methyl-Ether. “It’s perfect for the diesel process, meets ECA requirements and is also an economic winner since methanol and LNG are about the same price alongside ship,” he said.