Flexibility improvement and stochastic multi-scenario hybrid optimization for an integrated energy system with high-proportion renewable energy

A strong heat-power coupling limitation, uncontrollable renewable energy, and the grid's limited adjustment capacity deteriorate the operational performance and increase the renewable energy curtailment for the integrated energy system (IES) with high-proportion renewable energy. This paper presents the unavailable operating region problem of the traditional IES and its flexibility improvement mechanism of integrating with the gas boiler, electric boiler, power-to-gas (P2G), electrical energy storage and thermal energy storage. Subsequently, a two-stage optimization method is proposed to minimize the total cost containing the device investment, operation, carbon emission penalty and renewable energy curtailment penalty and further determine the capacity of such five devices. The hybrid model incorporates deterministic capacity optimization and uncertain operating optimization of considering variable condition properties of devices. Herein, the multiple uncertainties are captured by a series of stochastic scenarios generated by a stochastic hierarchy scenario generation model of integrating a Latin hypercube sampling method with a repeatable 0–1 scenario curtailment model based on Wasserstein distance. Eventually, a comparative analysis of the integration of five devices in terms of economic performance and renewable energy accommodation is presented by using an industrial park case. The results show that the integration of the gas boiler possesses the best economic promotion effectiveness and reduces the total cost by 49.56%. The integration of such five devices can reduce the renewable energy curtailment rate. Especially, the electric boiler and P2G can decline this rate to zero. However, the promoted results of P2G's integration are at the expense of sharp growth in the total cost.