• To facilitate the expansion of offshore wind energy, it is imperative to proactively secure installation vessels and the supporting infrastructure of marshalling ports. However, Mokpo New Port is currently the only domestic facility practically capable of executing installation operations. Consequently, there is a significant risk that port bottlenecks will materialize as deployment volumes scale up in the future. The critical challenge is that while the development of marshalling ports requires passing the Preliminary Feasibility Study (PFS) in a timely manner, the current port PFS framework may not fully reflect the roles and operational characteristics of marshalling ports in benefit calculations, which could lead to an inappropriate assessment of their economic feasibility. Accordingly, this issue paper reviews the current port PFS Guidelines from the perspective of offshore wind marshalling ports as ‘special-purpose infrastructure’ and proposes directions for regulatory improvement to ensure realistic benefit quantification.

• The logistics structure of a marshalling port is fundamentally distinct from that of a conventional commercial port. While cargo discharged at a conventional port is transported inland to reach the end-user (final destination), the final destination for offshore wind components is the offshore construction site, not the hinterland. Therefore, when assessing the benefits of marshalling ports, the concept of inland transport—a premise of the current PFS Guidelines—should be reinterpreted as ‘transport to the final destination.’ A valid approach involves quantifying benefits by substituting inland metrics with a maritime transport perspective, which is in line with the economic reality of the marshalling port's operational structure.

• From this perspective, this study categorizes the benefit structure of a marshalling port into the inbound leg (Manufacturing Port → Marshalling port) and the outbound leg (Marshalling port → Offshore Construction Site). The analysis specifically proposes a quantification framework for benefit of maritime transport cost reduction, focusing on the outbound leg, which accounts for a significant portion of operational costs. The central methodological issue addressed is whether applying Deadweight Tonnage (DWT) as the standard for average vessel cargo load—as mandated by current PFS Guidelines—is valid for marshalling ports. Offshore wind components are not only heavy but also oversized and non-standardized cargo. Consequently, actual load capacity is often governed by deck space utilization and sea-fastening constraints rather than weight limits. Therefore, applying a weight-based criterion implies an overestimation of the average vessel cargo load per voyage. This leads to an underestimation of the total number of required voyages, structurally resulting in the undervaluation of benefits of operational cost reduction that the marshalling port provides.

• To mitigate such distortions, this issue paper proposes interpreting average vessel cargo load as the ‘number of transportable sets per voyage.’ This recommendation is not merely a superficial change in unit notation. The ultimate objective of the PFS Guidelines in defining average vessel cargo load is to derive the ‘required number of voyages to process a specific cargo volume.’ Adopting a set-based interpretation is, therefore, a methodological adjustment designed to accurately implement this economic rationale, tailored to the unique characteristics of offshore wind cargo.

• Moreover, the value of marshalling ports extends beyond merely reducing vessel operating costs. The development of marshalling ports can yield significant time-value savings at the project level. These benefits include reduced vessel waiting times by resolving port bottlenecks, mitigated risks of project delays and downtime caused by weather constraints, and the minimization of financial costs due to schedule delays, as well as losses from delayed Commercial Operation Dates (COD). While this represents a benefit area of substantial potential magnitude, existing literature and the current PFS framework lack a standardized method to quantify these factors. Therefore, it is necessary to establish specific metrics to capture the time-value benefits of marshalling ports and to develop quantitative methodologies applicable within the PFS context. Additionally, regarding benefits of environmental cost reduction derived from shortened maritime transport 2 distances, the current PFS system lacks established calculation procedures and emission unit costs. Thus, the evaluation framework requires supplementation to adequately reflect these environmental benefits.

• In this issue paper, a simulation of the PFS was conducted for the marshalling port development project at Incheon New Port to quantify benefits and the Benefit-Cost Ratio (B/C). The results indicated that under the application of current PFS Guidelines, the B/C ratio struggled to exceed 0.5. Conversely, when applying the setbased average vessel cargo load framework proposed in this study, the average B/C improved significantly to approximately 0.934. Furthermore, in a sensitivity analysis incorporating realistic assumptions regarding installation vessels, the average B/C rose to 1.109. This confirms that Incheon New Port possesses sufficient potential in terms of economic viability.

• Refining the alignment of the PFS Guidelines is the starting point for resolving immediate bottlenecks in offshore wind infrastructure. Admittedly, improving the PFS framework alone does not automatically guarantee that offshore wind deployment targets will be met. However, for large-scale infrastructure investment to proceed in earnest, the specific functions and benefits of marshalling ports must, at a minimum, be rationally reflected in the evaluation framework. Only then can policy implementation gain the necessary speed. This issue paper aims to bridge the interpretative gaps in the current PFS process for marshalling ports and serve as a practical, foundational guideline for future feasibility studies regarding the expansion of regional marshalling ports.