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June 8, 2010

GL issues guidelines on gas as a ship fuel

Classification society Germanischer Lloyd (GL) has issued guidelines for using gas as a ship fuel in line with IMO regulations.

In force since May 1, they apply to all ships excluding liquefied gas tankers. The internal combustion engine installations subject to the IMO interim guidelines may be single-fuel (i.e. natural gas) or dual-fuel (gas and fuel oil) machines, and the natural gas may be stored in gaseous or liquid state. The guidelines are to be applied in conjunction with the relevant provisions of SOLAS.

Though gas was once banned as a ship fuel, new emission control regulations see it "reemerging as an environmentally and economically attractive option," GL Executive Board Member Dr. Hermann J. Klein, said at a press conference in Athens today.

In June last year, IMO's Maritime Safety Committee adopting Resolution MSC 285(86), "Interim Guidelines on Safety for Natural Gas-Fueled Engine Installations in Ships". Developed by the IMO subcommittee on Bulk Liquid and Gases (BLG) with GL assistance over the past few years, the Interim Guidelines are the first step towards the envisioned general code for gas as a ship fuel, the so-called IGF Code, which is currently under development by IMO and is expected to enter into force conjointly with the revision of SOLAS 2014.

The GL guidelines will help shipowners and shipyards prepare for the introduction of gas as a ship fuel in the near future. The new guidelines provide criteria for the design arrangements and installation of propulsion and auxiliary machinery to ensure a level of integrity, safety, reliability and dependability equivalent to that of comparable, state-of-the-art machinery burning conventional fuel oil.

Compared to oil, natural gas has two key advantages: high efficiency and a lower environmental impact. Engine problems and damage caused by low-quality heavy fuel oils will be a thing of the past for owners switching to gas as a ship fuel. Other risks associated with conventional ship fuels include bunker quality issues, poor ignition and combustion, and uneven heat and pressure distribution on pistons, piston rings and cylinder liners.

Liquefied natural gas (LNG) is gas (predominantly methane, CH4) that has been converted temporarily to liquid form for ease of storage or transport. It is odorless, colorless, non-toxic and non-corrosive. The reduction in volume makes it much more cost-efficient to transport over long distances. The energy density of LNG is 60 percent of that of diesel fuel. Therefore, you have to calculate with a doubling of tank capacity.

Increasing numbers of new LNG carriers are equipped with high-efficiency dual fuel engines. This new trend has encouraged the introduction of LNG as a ship fuel, though an appropriate infrastructure for supplying LNG fuel in ports has yet to be established.

The long-term future of heavy fuel oil as bunkers is questionable, both in terms of dependency on oil and not at least with regards to emissions. Natural gas in contrast gives a far more environmentally friendly combustion and in addition there appear to be greater reserves available than oil. Thus, natural gas in liquid form (LNG) as marine bunkers has the potential to be the solution for the shipping industry to cope with its emission challenges in the years to come.

"GL believes LNG as a ship fuel may be just the solution the shipping industry has been looking for to cope with the emissions challenges of our time," emphasizes Dr Klein.

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