Simulating Operating Performance of Alternative Configurations of LNG Bunkering Stations

Abstract

Recently, due to the great need to promote environmentally sustainable maritime transport, alternative energy sources to traditional fossil fuels have been proposed to reduce ship emissions. Among few alternative scenarios, most experts recognize Liquefied Natural Gas (LNG) as the most promising solution in the short to medium term. However, there are still some critical issues related to the future expansion of bunkering stations and the LNG-fuelled fleet. Firstly, there is the need for a sufficiently extensive international network of bunkering facilities. Secondly, the layout and location of bunkering stations impact the efficiency of ship bunkering operations, cost reduction and the safety of the surrounding areas. Last, the in-progress Russian-Ukrainian conflict is causing serious unbalances in gas supply and prices, especially for Europe. Specifically, in the case of Italy, gas imports represent the seventh most imported commodity. Due to the changed geopolitical scenarios, interest has arisen in investigating the technical and operational characteristics of LNG bunkering stations and comparing different configurations with a view to increasing Italy’s independence from other foreign countries, focusing on degasifies that could promote new infrastructures that make available LNG in ports. In this paper we highlight the importance of reducing ship emissions and investigate some technical and operational characteristics of LNG bunkering stations. We present a simulation study to analyse quantitatively the operating performance of different LNG bunkering technologies in a port terminal and their impact on the efficiency and overall cost within the whole goods’ supply chain. In particular, we evaluate and compare bunkering time, throughput and refuelling costs in alternative layouts, referring to marine terminals located near urban areas. The aim of this research is to verify whether ports with infrastructure embedded in metropolitan areas could provide, safely, a valuable contribution to the green transition by efficiently handling an adequate level of LNG supply, especially referring to the present Italian interest in increasing independence from foreign countries. For this purpose, we present four dynamic discrete event simulations of all the main LNG bunkering configurations and present their dynamic performance sampled over two consecutive years after a warmup period of 6 months. The simulation conceptual models have been created by the authors based on analyses of those configurations and then processed and implemented within the simulation software Witness Horizon 23®, used for experimentation. This is the first time that a simulation study is presented for comparing different configuration of LNG bunkering stations. The results presented here confirm that simulation is a key science to address these complex problems and it represents a major added value for the development of new infrastructures embedded in supply chains and able to favour green transition. Concerning the present study, the simulation output reveals that, although the increase in the price of LNG over the past year has had a strong negative impact on the propensity to activate LNG refuelling stations at maritime terminals, Truck-To-Ship, or Ship-to-Ship with small feeder ships, and Port-To-Ship configurations appear to be flexible and particularly suitable for port terminals located near urban areas. However, the final the choice of the most suitable LNG bunkering station requires further and specific inside investigation as well as considerations on the Decision Maker Strategies and Attitudes.