Aquifer Thermal Energy Storage (ATES) systems - current global practical experiences

As most of the industrial nations are located in the moderate climate zone with distinct summer and winter, global heating and cooling supply is less a matter of energy shortage than an issue of seasonal storage. Aquifer Thermal Energy Storage (ATES ) is capable of storing large energy volumes to bridge the seasonal mismatch between demand and supply of heating and cooling systems. However, there is a discrepancy in global ATES development, since more than 80 % of all ATES system are currently operating in the Netherlands and Scandinavia, which is mainly attributed to techno-economic barriers. Thus, this work analyses the technical performance of ATES based on monitoring data from 73 low temperature Dutch ATES systems. The analysis reveals total abstraction of 30 GWh of heat and 32 GWh of cold per year with average abstraction temperatures of 10 °C and 15 °C in summer and winter, respectively. However, while the temperature difference between abstraction and injection is 3-4 K smaller compared to the optimal design, the stored and abstracted amount of thermal energy is 50 % lower than the licensed capacities. This suggests inadequate interaction between the energy system and the aquifer as a result of the insufficient charging process of the subsurface. Nevertheless, the data showed only small thermal imbalances and small temperature losses during the storage period. Based on the comprehensive analysis, valuable conclusions can be drawn on the optimizations needs of current and future ATES projects.