Towards Net-Zero Shipping: A Review of Simulation Models and a Harmonization Framework

The International Maritime Organization (IMO) is pursuing reductions in greenhouse gas (GHG) emissions from international maritime transport. This paper presents a comprehensive review of simulation studies on IMO’s GHG measures, summarizing their simulation models and key components used. Our analysis reveals that these studies frequently rely on diverse assumptions that are often insufficiently documented, making it challenging to compare simulation results across studies. To address this critical issue, we propose a harmonized framework for maritime simulation models based on the review and findings. This framework provides structured variables and normalized units across domains, including demand, port operations, vessel characteristics, and fuel types, which the reviewed articles often assumed. The proposed framework is validated by an application example showing comparable tables of assumptions adopted by two different simulation studies. We anticipate that this framework will enable researchers to clearly present structured assumptions in their manuscripts, thereby enhancing readers’ understanding of assumptions and facilitating more efficient comparisons of simulation results across the field.