Abstract:
Underground pumped storage reservoir using abandoned coal mine could achieve not only high efficiency underground space utilization, but also realize a large scale renewable energy storage, such as wind and PV energy. This method also prevents abandoned mine from geological disasters. According to the mechanical strata environment of abandoned coal mine reservoir, this paper comprehensively introduces the concept, principle and technology of pumped storage underground reservoirin abandoned coal mine. This research explains that there are generally two scientific problems required to be solved in technical implementation: one is the influence of hydrogeology, hydro chemical characteristics and ground water circulation process on site selection; the other one is the influence of the stability and tightness of surrounding strata support structure during water circulation processes. The paper has also reviewed the technical framework of the pumped storage underground reservoir in abandoned mine.In view of the problems, the paper has analyzed the researches on the construction of underground pumped storage reservoir in abandoned coal mines, such as mine underground space utilization, rock mass stability and underground reservoir capacity, long term deformation of roadway surrounding rock and timeliness of support and the protection of water sources and water quality by water circulation. Furthermorethe paper has analyzed the four aspects of underground reservoir capacity, groundwater circulation, surrounding rock stability and water quality factors, which reveals the key factors for the construction of pumped storage underground reservoir in abandoned mine, and then providesthe accurate calculation of storage capacity of underground reservoir with the grasping of effective storage capacity of underground space. Appropriate water circulation couldfirstly ensure the reasonable storage capacity of underground reservoir, secondly ensure that the hydrodynamic process does not affect the safety of project,thirdly clarify the hydrogeological characteristics of the mine and the tightness of the reservoir, and fourthly keep the stability of underground space surrounding rock and the safety of reasonable storage capacity. Real time full space mine water monitoring is also required for water pollution prediction and prevention, which ensures the safety of groundwater quality and the safe manipulation of pumped storage equipment.Finally, the Quantai coal mine was introduced as an example,which could be taken as a pilot implementation for converting into a coal mine pumped storage power station. The feasibility of underground space in abandoned mines as pumped storage underground reservoir is demonstrated. The paper has made a useful discussion for the construction of underground reservoir in abandoned coal mines.