Thermodynamic research on natural gas/hydrogen fuel compressed air energy storage system by Xi'an Jiaotong University 

Technical Field: Compressed Air Energy Storage 

Development Unit: Xi'an Jiaotong University  Zhao Pan 

Article Title: Ning Ma, Pan Zhao, et al. Thermodynamic Analysis of Natural Gas/Hydrogen-Fueled Compressed Air Energy Storage System, International Journal of Hydrogen Energy 2024. 

Technical breakthrough: Research has shown that when the hydrogen mixing ratio is increased from 0.5 to 1, the system's round-trip efficiency, turbidity efficiency and energy density can be significantly improved, increasing by approximately 1.08%, 3.88% and 1.24% respectively. 

Application value: It provides a theoretical basis for the design and optimization of CAES systems, and helps to promote the development of energy storage technology, especially in the aspects of renewable energy grid connection and large-scale grid application. 

In recent years, the global demand for reducing fossil energy consumption and lowering greenhouse gas emissions has been increasing, making the development and utilization of renewable energy particularly important. The International Energy Agency (IEA) predicted in its "Renewables 2022" report that the global installed capacity of renewable energy would increase by 2400 gigawatts between 2022 and 2027, and it is expected that by 2040, renewable energy will account for 40% of global energy consumption. However, the volatility and intermittency of renewable energy sources such as wind and solar power pose challenges to grid security, especially in the case of a high proportion of renewable energy integration. Therefore, the development of energy storage technologies suitable for high proportions of renewable energy integration becomes crucial. Compressed Air Energy Storage (CAES) is a mechanical energy storage technology with long-term storage capabilities, and it is one of the only two commercial technologies with long-term storage capabilities. Due to its ability to establish storage chambers in abandoned mines, salt caverns, or artificial air tanks, it has less geographical condition restrictions compared to the Pumped Hydro Storage (PHS) technology. However, the existing commercial CAES technologies mainly rely on the combustion of fossil fuels to provide energy, which not only consumes fossil fuels but also generates carbon emissions.

To address this issue, a research team from Xi'an Jiaotong University proposed a non-isothermal compressed air energy storage (D-CAES) system using a mixture of natural gas and hydrogen as fuel, aiming to improve the environmental friendliness and thermodynamic performance of the system. A comprehensive thermodynamic analysis of the system was conducted, and the layout diagram is shown in Figure 1. The research results indicate that increasing the hydrogen mixture ratio can significantly improve the round-trip efficiency, turbidity efficiency, and energy density of the system. When the hydrogen mixture ratio increases from 0.5 to 1, the round-trip efficiency increases by approximately 1.08%, the turbidity efficiency increases by approximately 3.88%, and the energy density increases by approximately 1.24%. Additionally, they found that the turbidity damage ratio of the burner is the largest. By increasing the hydrogen mixture ratio, the turbidity damage can be significantly reduced. Through parameter analysis and sensitivity analysis, this study identified the key factors affecting the system performance, including the outlet temperature of the burner and the expansion ratio. The research results have important reference value for the design of sustainable CAES systems. This study also explored the performance changes of the system under different hydrogen mixture ratios under different operating conditions, providing a theoretical basis for the design and optimization of CAES systems. In summary, this study not only provides a new environmentally friendly solution for the development of CAES technology but also has significant importance for improving the performance of CAES systems and reducing environmental impacts. By using hydrogen as fuel, the D-CAES system is expected to become a cleaner and more efficient energy storage technology, contributing to the energy transition and achieving the goal of carbon neutrality.