From Coega to the world: integrated design and optimisation of a green hydrogen export value chain

The global transition toward low-carbon energy systems has positioned green hydrogen as a critical vector for decarbonising hard-to-abate sectors and enabling international energy trade. While demand for hydrogen is projected to grow substantially, many industrialised economies face domestic renewable resource constraints, necessitating large-scale imports. Resource-rich regions such as South Africa are therefore emerging as potential exporters, leveraging favourable solar and wind resources alongside strategic port infrastructure. However, the design of cost-competitive intercontinental hydrogen export value chains remains a complex challenge due to the interdependencies between production, conversion, transport, storage, and end-use decisions. This paper develops an optimisation framework for the design and operation of transcontinental green hydrogen export systems. A cost‑minimising transshipment model is proposed to represent the full value chain as a network of production sites, conversion technologies, storage facilities, maritime transport links, and destination markets. Key decisions including carrier selection (e.g., ammonia, liquid hydrogen, and liquid organic hydrogen carriers), fleet sizing, port infrastructure capacity, and destination pathways are considered to minimise the levelised cost of delivered hydrogen. The framework is applied to a multi-market export case study connecting South Africa to major demand centres, demonstrating the importance of system-wide optimisation in identifying cost-effective configurations. To enhance practical applicability, the model is embedded within an interactive Decision Support System, enabling stakeholders to explore scenarios and evaluate investment and policy decisions. The results highlight the value of integrated modelling in supporting the development of efficient and scalable global hydrogen trade systems.