Cost Analysis for Large ThermalEnergy Storage Systems

Thermal energy storage (TES) technologies play a key role in decarbonizing heat supplyand integrating renewable energy sources into heating systems. This study examines theinvestment costs of over 50 large-scale TES systems, including aquifer thermal energystorage (ATES), borehole thermal energy storage (BTES), pit thermal energy storage(PTES), and tank thermal energy storage (TTES) systems, based on desk and literatureresearch. The analysis considers inflation and purchasing power parity to enable cost com-parisons between regions and time periods and develops cost functions to enable investmentappraisal. The results highlight significant differences in the cost structures and the scal-ability of TES technologies. PTES systems benefit from economies of scale, making themcost-effective for large storage volumes. Due to higher specific costs, TTES systems aremore suitable for smaller applications. ATES and BTES systems show moderate economiesof scale. However, they remain highly dependent on geological conditions. Furthermore,the study introduces a new framework for calculating the levelized cost of storage, whichenables the comparison of different technologies by considering the cost of providingenergy at the target temperature level. This framework provides a more accurate assess-ment of the relative competitiveness of TES. By providing a transparent basis for evaluatingTES cost, the study's findings reduce uncertainty for decision-makers. Furthermore, thestudy recommends additional research to validate cost models and assess the practicalapplication of TES.