Underground Hydrogen Storage (UHS): Thermodynamic aspects and phase mass exchanges
E001
Abstract
In the context of energy transition, the intermittent nature of renewable energy resources necessitate the development of large-scale storage techniques. Underground salt caverns offer an option for storing energy vector gases like hydrogen. Such caverns are created by the solution mining technique. In this process, a single well, drilled from the ground surface to the targeted depth is generally used to inject fresh water and withdraw brine through a concentric tubing system, the so called leaching process. Once leaching is completed, the brine in the cavern is reduced to minimal quantities by a debrining phase where it is moved out by a gas injection operation. Based on the current energy needs, gas within the cavern will experience cycles of withdrawal and re-injection. The future increasing energy demands will necessitate almost daily solicitations of these caverns. Such fast charges, mechanical and thermal, are expected to impose several challenges that include:
1. investigating the widely adopted hypothesis of a uniform thermodynamic state in the cavern, and consequently the precision of the used codes embracing this hypothesis;
2. keeping good records of the cycled gas quantities, which necessitates studying all possible mass exchanges between the cavern phases (the gas, the brine, and the embracing rock salt).
This talk tries to provide some techniques to reply to the above mentioned challenges, and to project them for other applications that include underground hydrogen storage in porous media.