Comparative life cycle cost analysis of low pressure fuel gas supply systems for LNG fueled ships

The regulations of the international maritime organization (IMO) on ship emission are becoming increasingly strict. Liquefied natural gas (LNG) is an ideal alternative fuel for vessels, considering its environmental and economic advantages. In this paper, comparative life cycle cost (LCC) analysis of low pressure fuel gas supply systems (FGSS) for LNG fueled ships was performed. Nine cases with different ship scale and FGSS configurations were compared and analyzed, in which the BOG was handled by gas combustion units (GCU), auxiliary engines or reliquefaction devices. The variation of utility cost of FGSS during different stages of voyage was particularly considered. Moreover, sensitivity analysis was performed to investigate the influences of sailing time index, LNG price and lifetime on LCC. The study revealed that the LCC of FGSS depends strongly on ship scale, LNG fuel price and ship operation. BOG reliquefaction onboard is a feasible solution when the sailing time index is low and LNG price is high, especially for large scale ship. On the contrary, when the sailing time index is high and LNG price is low, it is more economic to supply the BOG to auxiliary engines after compression. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study conducted a comparative life cycle cost analysis of low pressure fuel gas supply systems for LNG fueled ships, finding that the LCC strongly depends on ship scale, LNG fuel price and ship operation. According to the research results, onboard BOG reliquefaction is a feasible solution when the sailing time index is low and LNG price is high; while supplying the BOG to auxiliary engines after compression is more economical when the sailing time index is high and LNG price is low.