2.2.4. Methodology Limitation

The main limitations of the methodology are that we considered (1) homogeneous and isotropic porous media and (2) pumping–discharge cycles defined randomly. However, these limitations do not interfere with the main objectives of this work that consist in providing general criteria regarding the impact of hydrogeological features on the efficiency and potential environmental impacts of UPSH. Clearly, during the design stage of future UPSH plants, we will need to develop more complex numerical models considering the heterogeneity of the porous medium and defining the pumping–discharge periods based on actual electricity price evolution.
