Probabilistic Analysis of Compressed Air Energy Storage Cavern Stability Considering Rock Mass Property Uncertainties

ABSTRACT: Compressed Air Energy Storage (CAES) in caverns is gaining prominence for its role in ensuring grid stability by storing surplus energy and releasing it as needed, thus addressing the intermittent nature of renewable energy sources. However, existing research on CAES caverns stability often overlooks inherent uncertainties in rock masses, approaching stability evaluations deterministically. This study addresses this gap by incorporating uncertainties in rock mass properties, conducting a probabilistic analysis of the mechanical responses during both the excavation and air-charging stages using numerical modeling with the point estimate method. Specifically, rock mass yield zone development and cavern displacement distributions have been obtained to assess cavern stability. Additionally, the effects of cavern depth, cavern size and the COV of rock mass deformation modulus on cavern stability have been investigated. The probabilistic analyses shed light on the impact of rock mass property uncertainties on cavern stability, offering valuable insights for a more systematic and rational approach to the CAES cavern design. 1. INTRODUCTION Wind and solar energy are emerging renewable energy sources being developed globally. However, wind and photovoltaic power generation exhibit intermittent and random fluctuations, urgently necessitating large-scale energy storage technologies to absorb renewable energy and to "smooth out" peaks and troughs in energy demand, thereby addressing technical bottlenecks in the development of renewable energy sources. Pumped hydro storage technology is mature and highly efficient, yet its implementation is constrained by factors such as site selection, ecological and environmental protection, and lengthy construction periods. Compressed air energy storage (CAES) is a promising technology solution that can store energy generated at one time for use at another time using compressed air. The CAES system operates by utilizing surplus electrical energy from the grid during periods of low demand to drive compressors that store air in storage containers. During peak electricity demand, this compressed high-pressure air is released from storage and expanded through a turbine to perform work, driving a generator to produce electricity for grid use. It can offer advantages including energy storage, grid stability and renewable integration by storing surplus energy from wind and solar and releasing it for later use during peak demand period (Qin et al., 2023, 2024).