Energy-carbon efficiency improving strategy for coal mine integrated energy system considering gravity energy storage

Abstract As an energy-intensive heavy industry, the coal mining industry plays a key role in achieving energy conservation and emission reduction. This study presents an energy-carbon efficiency improving strategy aimed at reducing carbon emissions and energy consumption in mining areas by integrating gravity energy storage (GES) with carbon capture and power-to-gas (P2G) technologies. Utilizing the natural topography, abandoned mines can be converted into gravity energy storage systems to stabilize the fluctuating outputs of renewable sources, such as wind power (WP) and Photovoltaic (PV). Concurrently, carbon capture, utilization, and storage (CCUS) technology capture CO₂ in mining areas, which is then transformed into methane using P2G systems. This methane is mixed with low-concentration coalbed methane to create a high-concentration combustible gas, facilitating carbon recycling and a collaborative multi-energy supply. The efficacy of the model was demonstrated through comparative simulations, which showed the utilization rate of renewable energy has increased, leading to a significant reduction in the total cost of the system and carbon emissions. This study confirms that optimizing gravity energy storage with CCUS-P2G effectively resolves the energy supply demand imbalance in mining areas, achieving economic and low-carbon advancements and offering theoretical support for the sector's low-carbon transition.