The Chinese government has set long-term carbon neutrality and variable renewable energy development goals for the power sector. The clean energy transition requires a co-evolution of innovation

investment

and deployment strategies for emerging energy storage technologies. Hydrogen could play a pivotal role as a long-duration energy storage in future low-carbon electricity systems

balancing inflexible or intermittent supply with demand. Cost projections are important for understanding this role

but data are scarce and uncertain. Here

we provide a techno-economic evaluation and uncertainty analysis of hydrogen as a long-duration energy storage

using a learning rate approach to estimate the long-term cost. We find that the levelized cost of hydrogen energy storage based on a modeled 25 MW system with proton exchange membranes technology is 3.981 yuan/kWh in 2025. Capital expenditure and equipment replacement costs are the top two contributors

accounting for 32.7% and 33.6%

respectively. Technological advancements and deployment scaling of electrolyzers and fuel cells are projected to drive the levelized cost of hydrogen energy storage down to 1.848 yuan/kWh by 2050 under an 18% learning rate trajectory. Although projections indicate that hydrogen energy storage remains less cost-competitive compared to mature technologies through 2050

like electrochemical storage and pumped hydro storage

its unique value proposition for long-duration storage and grid resilience sustains development potential in high variable renewable energy penetration scenarios.