A comparative analysis of optimizing hydrogen and battery shared energy storage in hybrid power generation systems

The global transition toward low-carbon energy systems has motivated shared energy storage (SES) as a critical solution for sustainable and resilient cities. However, integrating diverse storage technologies, such as batteries and hydrogen, involves complex techno-economic trade-offs. To address this challenge, this study proposes an integrated planning and operation framework for SES within energy systems under high renewable energy sources (RES) penetration, incorporating multiple storage technologies. A multi-objective optimization model is developed to simultaneously minimize total annualized system costs and maximize RES penetration ratio, while enabling flexible connections between renewable energy generation and storage facilities. Comparatively, the model evaluates battery energy storage and hydrogen storage systems in parallel, with hydrogen market participation included to enhance operational flexibility. Numerical case studies, conducted with an investment budget limit of 3 billion CNY (about 418 million USD), show that battery energy storage is more cost-effective when the RES penetration ratio exceeds 75 %. In contrast, hydrogen storage is economically feasible only when the penetration ratio is below 70 %, mainly due to energy losses in electrolyzers and fuel cells. Sensitivity analysis reveals that hydrogen storage becomes more cost-competitive than battery energy storage when hydrogen prices exceed 49 CNY/kg (around 6.83 USD/kg). Moreover, improving the efficiency of electrolyzers and fuel cells could narrow the competitiveness gap between these technologies. These findings provide valuable insights for policymakers and system operators in deploying SES systems based on local RES availability and market conditions.