This Research Topic is Volume II of a series. The previous volume can be found here:
New Development of Underground Energy Storage Using Mine Space Earth's temperature has risen by 0.08 °C per decade since 1880, but the rate of warming since 1981 is more than twice that, namely 0.18° C per decade. 2021 was the sixth-warmest year on record based on NOAA’s temperature data. In this regard, a consensus has been reached to reduce the usage of fossil fuels that have caused the majority of greenhouse gas emissions in the past decades. To replace fossil energy, solar energy, wind power, and other clean renewable energy sources have been soaring in growth. Yet their match rate with the practical power load still stays low due to randomness and intermittency.
Large-scale energy storage (CAES and PHES)—smoothly bridging the renewable energy and power load—can play an essential role in reducing greenhouse gas emissions. Particularly with regard to the difficulty in site selection for large-scale energy storage, using underground mine space as air/gas storage or water/liquid reservoir would ideally offer new options for energy storage, which could become a new measure of curbing global warming to below 2 °C and accomplishing the net-zero emissions by 2050 goal of the Paris Agreement on climate change.
During mining activities, large quantities of underground caverns/tunnels are formed. Using the underground space from abandoned mines would provide a new approach for underground energy storage site selection. The installation of energy storage plants requires geological stability and medium tightness. The energy storage is characterized by its fast-changing periodic load in storages, i.e., the high-frequency cyclic load. The mechanical stability and seepage stability of the energy storage chamber under the creep-fatigue effect caused by the high -frequency cyclic load strongly influence its normal operation. With mechanical stability, the underground storage chamber space is guaranteed to have integrity and acceptable shrinkage. The seepage stability ensures that the leakage of storage media (e.g., high-pressure air, pressurized water, and electrochemical fluid) would lie within the allowable safety margin.
The purpose of this Research Topic is to present and disseminate recent advances in stability studies of energy storage structures in underground mines, especially addressing strategies and scenarios of climate mitigation and adaptation. Potential topics include, but are not limited to:
• Continuous/discontinuous fatigue performance of underground surrounding rock, e.g., rock salt, sandstone, mudstone, and gypsum
• Damage evolution and self-healing properties of underground surrounding rock under the creep-fatigue coupled effect
• Thermodynamic/economic performance of energy storage systems using abandoned mines or underground spaces
• Long-term stability assessment for underground chambers from abandoned mines serving as energy storage
• Tightness/permeability evolution of storage medium, such as compressed air, pressurized water, and electrochemical fluids
• Strategies and scenarios of climate mitigation and adaptation using underground mine space for energy storage