Improving sustainability of maritime transport through utilization of Liquefied Natural Gas (LNG) for propulsion

Today, most of the merchant vessels use Heavy Fuel Oil (HFO) for propulsion. These heavy oils are cost effective but they produce significant amounts of noxious emissions. In order to respect International Maritime Organization (IMO) rules, Liquefied Natural Gas (LNG) as fuel for ships becomes an interesting solution as it allows to reduce nitrogen and sulfur oxides emissions. The study of the potentiality of LNG as fuel for ship propulsion is the aim of NGShiP, a research project carried out in Friuli Venezia Giulia – Italy, where the University of Trieste is a partner involved in the development of statistical model for maritime traffic data and process simulation models. In this paper the results of the maritime traffic statistical analysis are presented. In the analysis, the world ships traffic data for the month of May of three different years (2008, 2009, 2010) have been taken into account. The study allows to identify the vessel segments and routes that can benefit most from LNG installation. Results show that RoRo and tankers ships spend most of their sailing time in Emission Control Areas (ECA) and therefore they appear to be the best candidate for LNG installation. On this basis it has been decided to carry out an energy analysis of a tanker ship. Different energy recovery technologies have been considered and analyzed with the aim to improve ship efficiency and reduce environmental impact. Energy analysis results show that the use of LNG as fuel is interesting but important results can be obtained only if a mixture of energy saving/recovering technologies is considered. The analysis shows that an efficiency improvement as high as 15% can be achieved.