First Assessment of Potential Geological Reservoirs for Compressed Air Energy Storage in Portugal

Abstract

The increasing use of intermittent renewable energies bring challenges in their integration into the electrical grid. One of the solutions that may solve those challenges is energy storage. Compressed air energy storage (CAES) is a large-scale energy storage technology which may be a viable alternative to store energy in the form of pressurized air in times of excess of renewable energies power production. In this paper, we assess the geological resource potential as possible underground reservoirs for compressed air energy storage in Portugal. The suitable geological formations studied are host rocks, salt formations and saline aquifers. Their main geological characteristics, location and GIS spatial representation are done, as well as their suitability for CAES. Geological possible reservoirs were identified, mapped and are cross-checked with surface constraints and criteria such as renewable energy facilities. This work contributes to determine the potential sites which may hold reservoirs for the possible development of a CAES project in Portugal as a large-scale energy storage system. in order to achieve a future global integration of renewables and help to solve the challenges they bring to the grid.