Prioritising carbon reduction measures in Taiwan's shipping sector: A stakeholder-based comparison of IPA and IUI approaches.

The transition to low-carbon shipping presents a multidimensional challenge that extends beyond technological solutions and regulatory compliance. It also requires context-specific prioritisation that reflects stakeholder perspectives and implementation realities. This study examines 23 carbon reduction measures within Taiwan's maritime sector, evaluated from the viewpoints of seven stakeholder groups based on implementation cost, emission reduction potential, and capacity for adoption. To assist strategic planning, the measures are categorised into short-, medium-, and long-term options. While the Importance-Performance Analysis (IPA) method is frequently used to guide resource allocation based on stakeholder perceptions, it overlooks the feasibility of improvement. This study addresses that limitation by also applying the Importance-Unsatisfaction-Improvement (IUI) approach, which incorporates both subjective assessment and quantitative indicators to account for importance, dissatisfaction and ease of implementation. The results demonstrate a divergence between the two methods. IPA tends to favour high-cost, technology-based solutions such as alternative fuels-LNG and methanol, whereas IUI highlights more immediately applicable strategies including speed reduction and fleet renewal. These findings suggest that methods integrating feasibility-related dimensions offer a more grounded basis for decision-making. By integrating multiple stakeholder perspectives with dual evaluation methods and time-based classification, this study contributes a structured approach to prioritising decarbonisation actions in the shipping sector. The insights can inform government and industry efforts in developing practical, phased carbon reduction strategies that reflect both importance and implementation potential.