Utilization of a 3D webGIS to support spatial planning regarding underground energy storage in the context of the German energy system transition at the example of the federal state of Schleswig–Holstein

When decarbonizing a state-wide energy system by introducing a growing share of renewable energies, underground energy storage can help to deal with fluctuating electric grid feed-in from renewables like wind power. Since besides energy storage other subsurface usages can claim or effect possible scarce suited underground spaces and interact with other usages at the surface, subsurface spatial planning is a growing field of interest for state authorities and in science now. Combining two-dimensional surface geodata on concerned fields like regional planning and energy infrastructure with three-dimensional geological data into one coherent data model could therefore support spatial planners in identifying and locating underground entities suited for energy storage. In this paper, a volumetric grid-based concept to integrate two- and three-dimensional geodata into one coherent data framework is implemented, including available data sets on geology, energy infrastructure and existing spatial plans. Missing spatial data on regional electric energy production and heat energy demand are derived from available primary data. Upon this data basis, a self-developed open source-based 3D webGIS prototype is utilized to identify and visualize potential underground spaces for a compressed air energy storage use case scenario at the example of the federal state of Schleswig–Holstein in North Germany. A first basic and a subsequently extended query via the 3D webGIS on the developed data model provide spatial information on search domains for potential energy storage sites in salt rock structures that could be integrated into emerging subsurface spatial planning.