Recent advances in low-carbon hydrogen: Production, storage, and DC microgrid energy management under uncertainty

The integration of hydrogen technologies into renewable-rich direct current (DC) microgrids presents a viable route for long-term energy storage, system flexibility, and decarbonisation. However, existing studies largely review hydrogen production, storage, sustainability, and energy management in isolation, limiting system-level understanding under realistic operating uncertainties. This review addresses this gap by providing a unified assessment of hydrogen production pathways, storage technologies, green hydrogen sustainability, and uncertainty-aware energy management systems (EMS) within a DC microgrid framework. The analysis identifies, renewable-powered water electrolysis, particularly proton exchange membrane electrolysers (PEMEL), as the most suitable distributed hydrogen production option due to their fast dynamic response and DC coupling capability, while constrained by high capital cost and noble metal dependence. Hydrogen storage trade-offs exhibit critical influence on system design, with physical storage enabling fast-response services, while chemical storage supports long-duration energy shifting. Fuel cells enhance microgrid reliability through dispatchable clean power generation. However, under dynamic operating conditions, both electrolysers and fuel cells experience frequent start-stop cycling, high ramp rates, and thermal and pressure transients, requiring degradation-aware coordinated operation. The review further demonstrates that advanced EMS approaches including model predictive control, reinforcement learning and AI-based forecasting, are necessary for system component coordination, improved renewable utilisation, and degradation mitigation. Key research directions highlight the necessity of cost-effective advanced material development, AI-enabled EMS supported by digital twin platforms, global hydrogen standards and supportive policy frameworks for advancing resilient, cost-effective, and low-carbon energy systems.