Day-ahead optimal scheduling of a standalone solar-wind-gas based integrated energy system with and without considering thermal inertia and user comfort

Integrated energy system is an effective way to utilize renewable energy in a high proportion and reduce carbon emissions. However, renewable energy and load uncertainties bring great challenges to the optimal operation of the integrated energy system. The standalone integrated energy system shows the characteristics of excessive dependence on energy storage for the lack of large power grid support. To reduce the energy storage dependency and improve the scheduling optimization performance of the system, a standalone solar-wind-gas based integrated energy system (SWG-IES) is used to explore the relationship between uncertainties, thermal inertia and user comfort. Based on the characteristics of SWG-IES, day-ahead scheduling models with and without considering thermal inertia and user comfort are proposed. The optimization calculation and comparative analysis of four cases are carried out. Simulation results show thermal inertia and user comfort have significant impacts on day-ahead optimization strategy. After considering thermal inertia and user comfort, the utilization ratio of the battery and heat storage tank decreased by about 75 % and 30 % respectively, and abandoned heat occurred in certainty case. The function of thermal inertia and user comfort is equivalent to increasing the capacity of energy storage in the system, which has a positive impact on the large-scale and high-proportion use of renewable energy.