Marine Technology Reporter Blogs - lng

A limiting factor to the increase in the use of LNG fueled ships on a larger scale is the lack of LNG bunkering infrastructure worldwide, with exceptions being northern European countries which have been at the forefront on maritime LNG fuel development, such as Norway and Sweden. DNV GL recently launched a Recommended Practice for authorities, LNG bunker suppliers and ship operators, which provides guidance on how LNG bunkering can be done in safely and efficiently. According to DNV GL, LNG-fuelled ships have logged over 130 ship-years of operation in Norwegian waters. In some parts of the world, operators, suppliers and regulators have gained experience in all aspects of LNG-fuelled ship operations in recent years.

The use of liquid natural gas (LNG) as a marine fuel is increasing as new environmental regulations are enacted and bunkering facilities are expanded. Some forecast predict that around 10,000 vessels could be adopting LNG propulsion by 2020 compared to less than 100 today and classification society Det Norske Veritas had predicted that LNG would become the dominant fuel source for all merchant ships within 40 years. The main reason for this expected growth is because of strict emission regulations requiring the reduction of sulfur oxides (SOx) and nitrogen oxides (NOx) to 0.1 percent in Emission Control Areas (ECAs) by 2015 and 0.5 percent globally by 2020.

Rolls Royce and DNV engaged in a joint study of different fuel and engine configurations. The vessel selected for this study was the Rolls Royce designed UT 776 PSV. In the study, four alternative power system arrangements were considered, with two gas tank versions. The gen-sets were powered by various sizes of Bergen C-series diesel and gas engines and the dual fuel engine was a commercially available unit. For diesel and hybrids the assumption was that the exausts would have a SCR system giving a constant value of NOx reduction of 75%. In terms of cost, the diesel was the winner in the study as there is the added expense for other solutions of insulated LNG tanks.

The group that will be awarded the construction contract for this novel offshore LNG production unit will be known by October 31 Petrobras is keen to begin construction of the unit as it considers offshore natural gas liquefaction vital to guarantee a efficient output for the Santos Basin pre-salt gas. Many of the Santos Basin pre-salt fields are located over 300km from the coast, which convinced Petrobras to seek other options in order to deliver the gas to the market. Normally gas is transferred from wells to the coast through underwater pipelines but with such distances involved and with many of thereservoirs located in deep water…