An integrated interval-valued q-Rung Orthopair fuzzy DEMATEL–Choquet integral framework for prioritizing investment drivers of green energy in marine sector: A case study in Vietnam

Hoang Thai Pham (Logistics and Services Department, University of Transport Ho Chi Minh City, Ho Chi Minh City)
Chau Thuy Long Dang (Logistics and Services Department, University of Transport Ho Chi Minh City, Ho Chi Minh City)
Loi Quoc Le (Logistics and Services Department, University of Transport Ho Chi Minh City, Ho Chi Minh City)
Ngan Phuong Nguyen (Logistics and Services Department, University of Transport Ho Chi Minh City, Ho Chi Minh City)
Hung Van Bui (Logistics and Services Department, University of Transport Ho Chi Minh City, Ho Chi Minh City)
Hoang Phuong Nguyen (Faculty of Economics, Society and Environment, Academy of Politics Region II, Ho Chi Minh City)

International Journal of Renewable Energy Development
Vol 15, No 5 (2026): September 2026

With the rising demand for energy, the commitments to decarbonization and international regulations in the marine sector, the move towards sustainable maritime energy systems has become a strategic priority for Vietnam. It is thus important to understand what the most important investment drivers are in order to help with evidence-based policy development and effective resource allocation. This study aims to build an integrated framework using interval-valued q-rung orthopair fuzzy (IVq-ROF) DEMATEL and Choquet Integral methods to assess and prioritize the fourteen investment criteria that affect Vietnam's maritime energy economy. The expert judgements were gathered using the IVq-ROF linguistic assessment framework, which is used to capture uncertainty and interdependence between the criteria. DEMATEL method was used to identify causal relationships and the importance of the evaluation criteria, and the Choquet integral was used to include the interaction effects to arrive at final importance weights. The results show that three top investment priorities are the government incentives and financial support (0.095), the port energy infrastructure readiness (0.085) and compliance with IMO and national regulations (0.084). Stakeholder acceptance (0.046) and skilled workforce availability (0.054) have comparatively lower interaction adjusted importance, respectively. DEMATEL causal analysis identified port energy infrastructure investment cost (C1) as the strongest driving factor (highest D−R), whereas the interaction-aware Choquet ranking identified government incentives and financial support (0.095), port energy infrastructure readiness (0.085), and compliance with IMO and national regulations (0.084) as the three highest overall investment priorities. The proposed framework well reflects the linkages between economic, technical, environmental, regulatory, and social aspects and offers guidance for practical implementation of the maritime energy transition in Vietnam through integrated investment planning and sustainable infrastructure development to achieve the transition faster.