Hydrogen Used for Renewable Energy Storage: Techno-Economic Analysis of Different Technology Routes

Hydrogen energy storage system (HEES) is considered the most suitable long-term energy storage technology solution for zero-carbon microgrids. However, among the key technologies of HEES, there are many routes for hydrogen production, storage, and power generation, with complex choices and unclear technical paths. Therefore, this article analyzes the most economical technical path selection for HEES in the zero-carbon microgrid scenario with the optimal system configuration, using the LCOE (Levelized cost of electricity) as an evaluation index under four different renewable energy output and load characteristics. The results show that due to the need for long-term seasonal transfer of renewable energy, the cost of hydrogen storage has the highest contribution to LCOE. Low-cost hydrogen storage technologies can significantly reduce LCOE, such as liquid ammonia. In hydrogen production, alkaline is significantly more economical than PEM due to its low cost and high lifetime. In the power generation, this article compares different power generation methods, such as fuel cells, gas turbines, and internal combustion engines. The results show that LCOE is more sensitive to the efficiency of power generation systems, rather than cost. The main reason is that higher efficient can significantly reduce the investment scale of hydrogen storage. Therefore, reducing the cost of hydrogen storage and improving system efficiency are the key to improve the economy of HEES.