Due to the proposal of China’s carbon neutrality target, the traditional fossil energy industry continues to decline, and the proportion of new energy continues to increase. New energy power systems have high requirements for peak shaving and energy storage, but China’s current energy storage facilities are seriously insufficient in number and scale. The unique features of abandoned mines offer considerable potential for the construction of large-scale pumped storage power stations. Several countries have reported the conversion of abandoned mines to pumped storage plants, and a pilot project for the conversion of an underground reservoir group has been formalized in China. A feasibility study that considered the natural conditions, mine conditions, safety conditions, and economic benefits revealed that the construction of pumped storage power stations using abandoned mines could ameliorate several economic, ecological, and social problems, including resource utilization, ecological restoration, and population resettlement. The construction of pumped storage power stations using abandoned mines not only utilizes underground space with no mining value (reduced cost and construction period), but also improves the peak-load regulation and energy storage urgently needed for the development of power grid systems. Combined with the underground space and surface water resources of the Shitai Mine in Anhui, China, a plan for the construction of a pumped storage power station was proposed. The challenges faced by the current project were evaluated, further research suggested, and demonstration projects established in order to help achieve carbon peaking and carbon neutrality goals.

Under the carbon neutrality goal, coal enterprises must seek breakthroughs from abandoned mines, develop new resources in the new era, turn problems into countermeasures, and participate in the carbon emissions market, for contributing to the accomplishment of the national strategic goal of carbon neutrality. To this end, we investigated the relevant national policies and regulations to clarify the boundaries disclosed by the carbon information of enterprises, understood the development direction of carbon storage in abandoned mines, and clarified the transformation and development of carbon storage in abandoned mines. We made a few suggestions: (1) China should learn from its past experience and other countries to develop the energy industry with Chinese characteristics and reform the economic system. (2) Coal enterprises must actively respond to the national carbon information disclosure policy, clarify their own responsibilities and carbon emission boundaries. (3) It is necessary to proactively obtain advanced knowledge and plan carbon storage pathways for abandoned mines. (4) Development problems of coal enterprises should be deduced using cases. The ‘dual carbon’ goals should be achieved steadily step-by-step. (5) Three measures, i.e. improving the existing resource structure, coordinating the information of abandoned mines, and promoting the cultivation of scientific and technological talents.

The quest for carbon neutrality raises challenges in most sectors. In coal mining, overcapacity cutting is the major concern at this time, and the increase in the number of abandoned mine shafts is a pervasive issue. Pumped storage hydropower (PSH) plants built in abandoned mine shafts can convert intermittent electricity into useful energy. However, studies on basic theories and key technologies are a pressing issue. Six key scientific problems have been identified in PSH development in abandoned mine shafts that are relevant to China’s national conditions, current resource structure, and relative status of energy storage technologies in China and other countries. It is proposed that the research on pumped storage should move closer to the direction of intelligence, stabilization, and greening, and the construction and development should gradually realize integration, completion, and coordination. The goal is to realize integrated, complete, and coordinated development of PSH in abandoned mine shafts, streamline national policies concerning PSH, drive the co-development of industry, education and research, and achieve the carbon neutrality targets set by China.

Coal seam deformation due to gas adsorption affects the stability of the underground structure. Natural coal blocks of the Shanxi Formation were selected to study the dynamic adsorption characteristics of coal samples subjected to CO₂, CH₄, and N₂ gas injections under coaxial pressure and confining pressure (7 MPa), as well as the displacement of CH₄ with CO₂ and N₂ under the same conditions. The results show that, under the same conditions, the strain in the coal samples first increased, followed by a rapid increase along with the increase in pressure, with the transverse strain being always higher than the axial strain. The amount of gas adsorption varied from high to low as CO₂ > CH₄ > N₂, and the final adsorption strains and equilibrium times were different for each gas. Based on the increase in gas pressure, the gas adsorption strain curve can be divided into two stages. The displacement of N₂ only uses partial pressure to achieve the desorption of CH₄ in the coal sample, leading to shrinkage deformation of the coal sample. In contrast, the displacement of CO₂ has the dual effects of competitive adsorption and partial pressure reduction on CH₄, leading to the swelling deformation of the coal sample.