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Norwegian offshore oil and gas engineering specialist NLI Solutions (NLI) has developed a concept for an LNG bunker barge based on the NLI LNG tank design. The concept has been further developed in a design study together with the marine division of Rolls-Royce and Wilhelmsen Technical Solutions (WTS).

In a statement, NLI said: "LNG is among the cleanest and most cost-efficient options for low emission shipping. Interest in LNG as a marine fuel is rapidly increasing, but one limiting factor is practical availability of LNG bunker facilities. LNG bunker barges are often described as the 'missing link' in the LNG supply chain. Today, only one example exists, capable of carrying 187 cubic metres (cbm) of LNG, even though ocean-going ships need to bunker several thousand cbm."

The LNG barge is designed to meet the multiple demands of a cost-effective, high-tech, high-volume barge.

For safe operations and increased manoeuvrability, the barge will be equipped with podded propulsion, similar to those used in offshore support vessels, as well as state-of-the-art electronics for early threat detection.

The NLI LNG tank is an atmospheric, prismatic steel tank, type 'B', with a capacity of 4000 cbm of LNG. It will be fitted with a new insulation system with very low levels of boil-off gas.

Onboard power and propulsion are fed by an environmentally-friendly gas engine. The barge has a large pressure tank on the aft deck for boil-off gas handling and gas delivery to the engine.

Since re-condensation equipment is very expensive, takes a lot of space, and has very low efficiency for small installations like this, excess boil-off gas can be delivered to a shoreside gas grid when the barge is not carrying out bunkering operations. The vessel can also deliver electric power to a shoreside electric grid.

The various planning tasks have been divided up as follows:

NVC – responsible for design, Bergen gas engine, pod drives and bridge systems;

TI Marine Contracting (part of WTS) – responsible for insulation systems;

NLI – responsible for tank, LNG/gas systems, bunkering systems;

Det Norske Veritas (DNV) – evaluation of the barge concept with respect to limitations and possibilities within the existing codes and regulations.