To overcome the natural temporal fluctuations inherent in the production of renewable energy is a requirement for the transition to renewable energy sources such as wind or solar power. Energy storage provides a solution to the time shift between energy production and demand. Storage options for renewable energies include the conversion to and storage of secondary energy carriers like compressed air, hydrogen and methane as well as heat, and the geological subsurface holds a large potential of storage capacities, e.g. in salt caverns and porous formations. In the ANGUS+ project the potentials and implications of energy storage in the geological subsurface are investigated.
Within the project, storage formations are characterised by physical and chemical properties, and the processes induced by energy storage applications are parameterised based on literature studies and laboratory experiments. This new parameter database feeds numerical modelling tools developed and implemented within the project to simulate the coupled thermal, hydraulic, mechanical, chemical and microbiological processes induced by subsurface energy storage applications and their interaction with other types of use of the geological subsurface. Based on the enhanced processes understanding in the geological subsurface, virtual scenarios of gas storage in salt caverns and deep porous formations as well as scenarios of heat storage in the shallow and moderately deep subsurface are developed. The numerical simulation of energy storage operations helps predicting impacts on protected resources and deducing appropriate monitoring methods.
With regard to potentially competing options of underground use, first concepts of subsurface spatial planning will be developed in the ANGUS+ project. Within the framework of two guidelines on energy storage in the deep and shallow subsurface, respectively, application-oriented recommendations deduced from the project results will be made available to planners and policy makers.