Synergistic integration of liquid air energy storage and ammonia synthesis: Enabling flexible, low-carbon industry with enhanced energy storage

With the increasing integration of renewable energy into the power grid, large-scale energy storage technologies have become essential for addressing the intermittency and volatility of these sources. However, standalone liquid air energy storage (LAES) systems exhibit relatively limited efficiency, while conventional large-scale ammonia synthesis processes face challenges such as high carbon emissions. To overcome these issues, this study proposes a novel multi-energy coupling integrated system that combines LAES with ammonia synthesis (LAES-NH3), aiming to achieve synergistic optimization of energy and material flows, enabling clean ammonia production powered by green electricity and green hydrogen. During valley times, the system uses low-cost electricity to drive the LAES subsystem (S-LAES) to produce liquid air, which serves as the feedstock gas for ammonia synthesis. During peak times, the concentrated heat released from the ammonia synthesis reaction is recovered to drive the expansion unit of the S-LAES, thereby enhancing the overall power generation efficiency and output of the system. Thermodynamic analysis and economic evaluation indicate that the integrated system achieves a maximum overall round-trip efficiency (RTE) of 62.89%, and the S-LAES can reach the RTE of 103.7%. The system demonstrates a minimum dynamic payback period (DPP) of only 3.26 years and a net present value (NPV) of up to 1.275 billion USD over its 30-year lifecycle. The study confirms that the LAES-NH3 system combines both technical feasibility and economic competitiveness, offering a flexible, chemically productive energy storage solution for large-scale, long-term integration of renewable energy.