Optimal economic and low-carbon scheduling in integrated energy system considering multi-level thermal energy coupling and integrated demand response

In integrated energy systems (IESs), thermal energies with different characteristics and efficiencies are typically regarded as having the same thermal energy level, which leads to unreasonable assumptions regarding the thermal energy structure of the system. Moreover, the traditional optimal operation method does not consider the impact of expanding a single thermal energy flow into a multi-level thermal energy flow on the optimal operation results of the system. These problems pose challenges to the complexity of multi-level thermal energy flow mechanisms and optimal operation results of the IES. To tackle this challenge, first, this study establishes a multi-level thermal energy coupling (MTEC) model, which divides the thermal energy flow into three levels according to temperature, and re-models the production and conversion equipment based on thermal energy levels. Second, the energy hub matrix for MTEC-IDR joint operation is proposed, and the integrated demand response (IDR) is introduced to replace energy storage devices to solve the problem of rising costs caused by insufficient load flexibility. Finally, the system constraints and objective function are improved, and an optimal IES scheduling strategy under the MTEC-IDR mechanism is proposed. The effectiveness of the proposed strategy is proved from the perspectives of low-carbon implementation and economy.