Techno-economic challenges of alternative fuels in port operations: A literature review connected to storage, transport & distribution, and bunkering in the maritime sector

Abstract

The maritime sector is in need of decarbonization to lower GHG emissions and to fulfill goals set by IMO. This thesis analyzes hydrogen, methanol, and ammonia as alternative fuels to traditional fuels. The purpose of this thesis is to analyze the selected energy carriers' techno-economic challenges in terms of transportation, distribution, storage, and bunkering. Based on scientific articles published up until 2023, the primary emphasis according to the reviewed research in this thesis is on hydrogen, followed by ammonia, and finally methanol. Methodically, this thesis investigates literature published on the scholarly database Scopus and reviews case studies in order to comparatively assess the challenges and viabilities of the selected alternative fuels. Common challenges found in the scientific literature reviewed, includes lower density than conventional fuels, safety hazards, and redevelopment costs. Of the three alternative fuels investigated, hydrogen requires the largest storage facilities, the most significant investments for development, and is the most expensive to transport. Whereas ammonia benefits from pre-existing infrastructure as it is used within other sectors. However, both ammonia and hydrogen require special storage units, and suffer from boil-off, leakage, and need investments in bunkering facilities. Methanol does not have any special individual challenges and notably, the mean transportation costs via vessel for methanol is 0,77 USD/GJ/10 000 km which is a fraction in costs compared to hydrogen at 41,89 USD/GJ/10 000 km and ammonia at 5,71USD/GJ/10 000 km. In conclusion, hydrogen faces the most prominent challenges, despite the fact that more research is being published than ammonia and methanol. Methanol has the least techno-economic challenges but is on the other hand notcarbon free. Therefore, methanol is not a viable option to obtain zero carbon emissions from ships.