DFDE and Steam Turbine Propulsion System, Energy Efficiency Operational Index comparison on board LNG Carrier

Abstract

The strong world demand for energy has increased the need for Floating Storage Re-gasification Unit (FSRU) and terminals. Due to geopolitical tensions, it is predicted that large volumes of liquefied natural gas (LNG) will be transported during the coming years, which leads to an increase in the number and size of LNG Carriers. In that context, the fourth GHG of IMO made an emphasis on environmental issues with respect to air emissions. Traditionally for LNG Carriers, the propulsion efficiency of the steam turbine propulsion system can only achieve 30%, the DFDE propulsion system exceeds 42% for an LNG Carrier; this represents a reduction of 1/3 of fuel consumption impacting the overall energy efficiency. In addition, the flexibility of electric propulsion increases the reserved volume to the cargo. The present paper provides the case study of an Algerian maritime company first Dual Fuel Diesel Electric LNG Carrier. To demonstrate the energy efficiency of the DFDE Propulsion system, a comparison between two LNG Carriers with approximately the same principal dimensions are carried out. The study reveals that the DFDE propulsion system for LNG Carrier reached an optimized Energy Efficiency Operator Index (EEOI), compared to LNG Carrier fitted with steam turbine propulsion system over the same voyage profile.