A novel in-situ electric heating high-temperature aquifer thermal energy storage system for renewable energy curtailment accommodation

The volatility and intermittency of renewable energy power generation such as wind and solar energy have led to a severe electricity curtailment problem. As a seasonal thermal storage technology featuring large capacity and low cost, High-Temperature Aquifer Thermal Energy Storage (HT-ATES) provides an effective solution for renewable energy accommodation. However, traditional HT-ATES systems suffer from low thermal recovery efficiency due to buoyancy flow induced by hot water injection, which restricts their large-scale application. To address this issue, this study proposes a novel in-situ electric heating HT-ATES method that directly heats the aquifer matrix by leveraging the uniform heating characteristic of solid electric heating technology. An electro-thermal-fluid multi-physics coupled numerical simulation model was established, and its reliability was verified via scaled-down experiments. Simulation results show that the thermal recovery efficiency of a single module of the novel HT-ATES system is significantly higher than that of the traditional system; after 90 days of operation, the average temperature of recovered hot water reaches 84.65 °C, and the energy storage capacity per unit aquifer volume is increased by approximately 57.1% compared with the ground heat exchanger method. Finally, the system configuration was optimized through parameter sensitivity analysis, and the potential of the novel HT-ATES system to accommodate renewable energy curtailment was verified based on the electricity curtailment data of a wind farm in Northeast China.