Objective The integration of offshore wind power and hydrogen production enables the cross-regional transmission of electricity, which is of significant importance for promoting the high-quality development of renewable energy within power systems. As a turnkey model integrating design, procurement, and construction, the EPC approach can effectively consolidate resources and improve project quality. However, the complexity and long-term nature of offshore wind-to-hydrogen EPC projects have hindered comprehensive quantification and analysis of investment risks.

Method To address the above issues, this study constructed a systematic risk indicator framework for the investment planning stage of offshore wind-to-hydrogen EPC projects. Considering the uncertainty of indicator attributes and weights as well as decision-makers' risk preferences, an investment risk assessment model using TODIM-improved PROMETHEE-II was proposed, which incorporates hesitant intuitionistic fuzzy linguistic terms and triangular fuzzy numbers.

Result The proposed model is applied to case studies and further examined through sensitivity analysis. Results indicate that, among offshore wind-to-hydrogen investment projects, the Shandong region demonstrates a significant regional advantage, and that C₄₂ (environmental protection) and C₁₂ (electrolytic efficiency risk) exert substantial influence on project selection, exhibiting high sensitivity.

Conclusion The case study results validate the effectiveness and reasonableness of the proposed investment risk assessment model.