Energy storage in deep salt formations: geological and geomechanical conditions and potentials with a focus on Latin America

The storage of energy in the form of natural gas in deep, artificially created salt caverns is a proven technology. It balances potential imbalances between the supplier (supply and production of natural gas) and the customer (demand and consumption of natural gas), thus ensuring an opti-mal energy supply in times of crisis. From an engineering point of view, rock salt formations are particularly suitable for the storage of natural gas or oil due to their tightness against gases and liquids and the creep behavior of the material. The goals of global climate policy and the associated reduction of carbon dioxide emissions into the atmosphere demand the sustainable use of artificial caverns for the storage of green hydrogen, which is currently being scientifically monitored in pilot projects. In order to achieve an eco-nomically viable and mechanically safe energy storage, the geological and geomechanical conditions of the salt rocks that support the caverns at great depth must be studied, which requires specialized work both at the laboratory scale and through pilot tests. In this article, we present the main features required for some well-known salt formations and their potential for the underground storage of hydrogen and compressed air in caverns. To do this, geological and geomechanical boundary conditions for the potential analysis must be defined and, for the specific design and operation of a cavern, evaluated on a case-by-case basis. The storage capacity depends, among other things, on the maximum injection and withdrawal rate, as well as the minimum and maximum pressures to be respected, and the prevailing geological boundary conditions. Particular attention is paid to an overview of salt deposits in Latin America and especially Colombia. The salt deposits near Bogotá and on the Brazilian coast appear to be of interest for a more detailed analysis for underground gas storage in salt caverns. However, a conclusive assessment of the salt deposits requires precise knowledge of the existing geology and the storage needs and possibilities of the respective countries or regions.