Numerical simulation of cyclic performance of compressed carbon dioxide energy storage system in aquifer

The boom of renewable energy has been overshadowed by two problems: the intermittency and volatility of such energy. Largescale complementary energy storage has been required to solve these problems. This paper proposes a compressed CO2 energy storage system in aquifer (CCES-A), aiming to storage energy efficiently at a low cost. Firstly, the feasibility of compressing CO2 in the aquifer had been proved through numerical simulation, and the CO2 compression in the aquifer had been emulated by a wellbore-reservoir coupling model. The operation of the CCES-A had been divided into the establishment stage of the initial airbag, and the cyclic stage of energy storage and release. The proposed wellbore-reservoir coupling model had been applied to analyze the wellhead pressure, energy flow and energy recovery rate of weekly, monthly, and seasonal cycles, as well as the energy recovery efficiency at different injection temperatures. The simulation results showed that under the three cycles, the wellhead pressure increased with the number of cycles. The energy flow and energy recovery efficiency decreased with the growing the number of cycles. The energy recovery became more efficient with the rise of the injection temperature.