PHOS-UK: Open-source user interface for power-hydrogen-heat optimisation for the United Kingdom

This paper introduces PHOS-UK, an open-source graphical user interface (GUI) and optimisation-based decision-support tool for optimal planning of integrated energy infrastructure in the United Kingdom (UK), including electricity, hydrogen, heating, and CO 2 infrastructures. PHOS-UK is structured around two main architectures: a hydrogen optimisation framework and a hybrid power–hydrogen optimisation framework. The platform provides a flexible environment that eliminates the need for coding or direct interaction with complex optimisation models. Users can execute models using a wide range of commercial and open-source solvers and explore results through an interactive energy dashboard with diverse spatial and temporal resolutions. A distinctive feature of PHOS-UK is its capability to support decision-making under uncertainty in the hydrogen optimisation framework, including variability in renewable resources, energy demand, technology efficiency, and cost projections. For this architecture, the platform implements two-stage stochastic programming with scenario generation and reduction, alongside deterministic and robust (adaptive and static) optimisation methods, thereby allowing users to configure, reduce, and execute custom scenarios. In contrast, the hybrid electricity–hydrogen module is currently implemented under deterministic optimisation. A demonstration case study illustrates that PHOS-UK can handle large-scale optimisation problems and communicate results effectively through effective visualisation. This platform represents an important step towards open, transparent, and accessible decision-support tools, enabling stakeholders to evaluate electrification and hydrogen pathways for the UK’s net-zero transition.