The Naval Architect: July/Aug 2019
Even though LNG has fuelled a variety of ships since 2000, its appeal and primary use has centred on large energy-demanding vessels.
This pigeonholing is, in part, due to the weight of LNG tanks and the space they require. As class society DNV GL states, LNG tanks “typically occupy three to four times the volume of an equivalent amount of energy stored in the form of fuel oil”.
The inefficiency of heavy and expensive LNG tanks has deterred some shipowners from investing in LNG-powered newbuilds or retrofitting older vessels. But a new project, which erases the loss of payload and transportation capacity usually necessitated by the installation of traditional tanks, may make LNG a more compelling choice.
Dubbed SpaceTech4Sea, the project involves the adoption of aerospace technology and “novel shipbuilding techniques” to develop an ultralight LNG fuel tank.
Headed by the Athens-based marine consultancy Ocean Finance in partnership with the American Bureau of Shipping (ABS) and Cimarron Composites, it aims to introduce LNG as marine fuel across a wider spectrum of vessels. Last year, it was awarded a grant of €1.1 million from the European Commission as part of a push to boost the Blue Economy.
Made of all composite carbon fibre and wrapped in an advanced resin, the cylindrical tank can withstand the cryogenic temperatures required to store LNG. Unlike a metallic tank, it is non-corrosive, won’t microcrack and is incredibly lightweight.
“We are saving almost 85-90% of the weight” compared with the average LNG tank of the same net volume, says Panayotis Zacharioudakis, the director of the Ocean Finance. “So, the weight is only the weight of the fuel, not of the tank.”
The concept for the project arose in 2016, during which time the consultancy group was trying to design a high-speed catamaran powered by LNG. However, upon realising the LNG equipment would account for 20% of the vessel’s total weight, a new plan had to be devised. The team turned to the most weight sensitive industry they could think of for ideas – the aerospace industry, where, as Zacharioudakis says, “every gram counts”.
“The advantages of this technology are that by having less weight, it is much easier to locate the tank in other places compared to standard metallic tanks the market is currently offering. You also don’t need to reinforce the substructure of the vessel that is going to hold the tank.”
The space-ready technology has been downgraded for use in the marine environment, as it does not have to endure such extreme conditions at sea as it does in space. Additionally, the tank has been tested for use with liquid oxygen and liquid hydrogen, which have much lower storage temperatures than LNG.
The tank will eventually be validated for liquid hydrogen and slush hydrogen. This will help future-proof the technology if LNG – which is often cited as a transition fuel on the road to decarbonisation – finds itself overshadowed by zero-emissions fuels like hydrogen and ammonia.
At the moment, Cimarron – a composite developer based in Huntsville, Alabama – manufactures and owns the property rights to the technology while Ocean Finance has a commercial agreement for its commercial exploitation in Europe. Cimarron will later make a technology transfer to the consultancy group to marinise the project and, depending on market demand, help set up a production facility in Greece from a respective joint venture.
SpaceTech4Sea is expecting Approval in Principle from ABS’ Global Ship Systems Centre in Greece for the product shortly. A pilot project to test out the tank is also underway with an unnamed Greek shipping company.
