As more economic sectors and industries are increasing activities offshore, marine multi-use projects are becoming increasingly attractive. These collaborative deployments require new investigations into environmental impact, logistics, regulation and financing.

In this brief, the authors perform a systematic review of online information on M4 projects and insights from semi-structured interviews, showing that combinations of offshore wind energy and hydrogen production are highly promising M4 alternatives. A further techno-economic analysis to evaluate centralized and decentralized offshore hydrogen production strategies based on the hydrogen production cost shows that centralized hydrogen production offshore with subsequent transmission to land via pipeline is the alternative with the lowest LCOH (levelized cost of hydrogen).

However, modular design at smaller scales should also be explored to assess profitability and project feasibility in future studies, and the authors’ analysis reveals that LCOH showed the highest sensitivity to the assumed electricity cost. For successful future marine multi-use projects, development of clear frameworks for simple permitting and effective space-sharing between uses is necessary and must consider local contexts and realities.