State-of-the-art expansion planning of integrated power, natural gas, and hydrogen systems

Renewable hydrogen is considered key in the transition towards a carbon-neutral future. This is due to its spatio-temporal storage and sector coupling potential, which has seen it referred to as energy vector. However, many unresolved issues remain regarding hydrogen's large-scale deployment, e.g. least-cost production, optimal facility siting, and overall implications on power and energy systems. Expansion planning provides an option to study these issues in the holistic context of energy systems. To this end, this article presents a comprehensive review on state-of-the-art expansion planning models that consider integrated power, natural gas, and hydrogen systems. We cluster the existing literature in terms of modelling themes and scope, study the applied systematic modelling characteristics, and conduct an in-depth analysis of the technical model features regarding hydrogen technologies and natural gas infrastructure. Finally, we identify and discuss research gaps in the existing literature.