Green hydrogen production and renewable energy storage integration: A review of technologies and system pathways

Green hydrogen has emerged as an important complementary enabler of deep decarbonization, offering a versatile, low-carbon energy carrier that complements renewable electricity systems. This review synthesises recent studies on green hydrogen production and the integration of renewable energy storage, focusing on technological developments, system optimisation approaches, and lifecycle sustainability assessments. This review proposes an integrated conceptual framework linking renewable hydrogen production, hybrid energy storage systems, AI-driven optimisation, lifecycle environmental assessment, and emerging policy mechanisms. Electrolysis technologies such as PEM and AEM are best suited for variable renewable sources due to their rapid dynamic response. However, challenges persist regarding material durability and cost. Advanced control strategies, including grid-forming converters, have been shown to reduce energy losses by 34.27% and storage demand by 67%. Integrated storage systems, such as sand thermal storage with a levelised cost of €114-€198/MWh and PHES with 117% improved utilisation, serve as important complementary enablers for aligning renewable energy supply with hydrogen production demand. The LCOH ranges between $3.30 and $3.85/kg in optimised hybrid systems, while electrified-SMR with CCS achieves up to an 82% reduction in emissions. Life cycle assessments confirm that solar- and wind-based hydrogen can achieve near-zero operational emissions. However, unresolved challenges in regulation, infrastructure, and public acceptance remain. This review identifies key gaps and proposes future research in the optimisation of AI-based systems, circular electrolyser manufacturing, and harmonised hydrogen certification. The article provides novel, cross-sectoral insights into emerging best practices and system-level innovations, offering a strategic roadmap for scalable, low-carbon hydrogen deployment.