The most modern technical systems are an integration of various energy converters and sources of various physical nature. Mechanical, thermal, electromagnetic, as well as computer (information) monitoring and control system. Multi-energy systems (MES) also belong to the class of such technical devices. The main task in creating mathematical models is a methodological approach that allows joint modelling of 6 energy objects of various nature on a single methodological basis. The article considers the main approaches to the mathematical description of MES, as well as the assumptions and stages of formation for modelling this class of technical systems. The main advantages and disadvantages of the proposed methods for creating mathematical models are considered taking into account the possibility of using optimization methods and using the above models as digital twins for control systems. In addition, the article will present a methodological approach to the formation of mathematical models of an integrated energy system based on the concept of an energy hub using MATLAB.