In the building heating/cooling sector, utilizing renewable energy sources is often challenging due to a significant seasonal mismatch between peak energy demand periods and peak thermal energy supply periods. To effectively address this misalignment, one possible solution is to use seasonal energy storage systems. In this context, underground thermal storage systems, known as Aquifer Thermal Energy Storage (ATES), present significant potential.

This report presents the technology, potential, and various types of ATES systems, as well as their distribution on a global, European, and national scale. Globally, there are over 2,800 systems, with a total amount of energy extracted for heating and cooling exceeding 2.5 TWh/year. None of these systems are located in Italy; currently, there are no ATES projects in our country, despite favorable geological conditions due to the presence of extensive alluvial basins.

A preliminary site, termed “Areale Ravenna,” located in Emilia Romagna, was identified based on data availability and geo-hydrogeological characteristics. Initial 3D numerical simulations have been conducted for this area. The aim of these simulations is to investigate whether the GeoSIAM – Integrated System for Geo-Modeling Analysis, developed by RSE in previous years of System Research, is suitable for ATES applications. For this area, a detailed 3D static geological model was created, and two numerical simulations were performed: the first assuming the seasonal use of the shallow aquifer (consistent with an LT-ATES system), and the second simulating the storage of excess hot water, such as that produced by a Renewable Energy Source (RES) system, at a significantly higher temperature than that of the aquifer (HT-ATES). These simulations were conducted using information and parameters from literature but do not currently refer to any actual industrial projects. The results of these initial simulations were evaluated against available literature data for real-world applications to assess the suitability of the GeoSIAM code for simulations of this type.