Feasibility study of diesel engine replacement on passenger ships: a system dynamics approach

As an archipelagic country, passenger ships are used as the inter-island transportation mode. PT. PELNI is one of the shipping line companies operating some passenger vessels in Indonesia. As the total time of ship operated is getting high, the main engine will be slowly deteriorating. This paper took three ships with varied age of ship, namely KM Gunung Dempo, KM Labobar, and KM Dobonsolo, owned by PT. PELNI as the case studies for analyzing the age determination of ship diesel engine replacement using system dynamics (SD) approach. System dynamics has become one of the most frequently used approach to deal with a decision-making problem for a complex system. There are two major variables considered here, operational expenditures (OPEX) and capital expenditures (CAPEX). CAPEX consists of docking cost for engine replacement, purchasing the dual-fuel engine and liquefied natural gas (LNG) ISO tanks procurement, and cost that caused by the conversion of the cargo spaces into the LNG storage tanks. OPEX variable consists of all costs that related to the operations of the ship, such as fuel oil (FO) consumption, lubricating oil consumption, maintenance cost, and engine overhaul cost. These two variables, CAPEX and OPEX, represent the difference between conventional diesel engine and dual-fuel diesel engine. There were 18 scenarios applied to each ship with variations of LNG price, FO price, and the maintenance cost. The result shows that 14 scenarios are categorized under feasible scenario for KM Dobonsolo with the average profitable life of 2.22 years; 17 feasible scenarios for KM Labobar and 16 scenarios are feasible for KM Gunung Dempo with the average profitable life of 11.72 years and 15.17 years.