ABSTRACT
Sundsvall Energi owns an existing rock cavern, built in late 1980’s, previously used for storage of liquefied petroleum gas (LPG). Sweco, the project designer, have explored the feasibility to convert the existing unlined rock cavern into an intermediate storage for carbon dioxide (CO2) in a liquid state at approximately -23.5°C and a pressure of 22 bar. The proposed technical solution includes taking advantage of the properties of frozen groundwater within the surrounding bedrock to create a sealed zone, ensuring containment of stored CO2. The technical feasibility of this method presents a set of challenges, due to the combination of low operational temperatures and a pressure that significantly exceed the groundwater pressure of approximately 8 bar. The key challenges include ensuring the stability of the rock cavern during the cooling and pressurization processes, as well as confirming the adequacy of the frozen zone to maintain the integrity of the storage.
