Mixed-integer linear programming formulation of combined heat and power units for the unit commitment problem

Abstract

The energy system in Europe changes towards a smart energy system with interconnection of heat, power and gas networks, increasing the flexibility and efficiency. Combined heat and power units play an important role in such systems, since they have a high total efficiency and enable the interconnection between the networks. Yet, control concepts are needed to ensure an optimal operation planning of available capacities. The resulting unit commitment problem can be approached with mixed-integer linear programming. This paper presents a generic modelling method of coupled and decoupled combined heat and power units with mixed-integer linear programming. Furthermore, operation data of two steam turbine types are compared with the model performance to demonstrate the feasibility of this modelling approach. Finally, a model of a combined cycle is presented, derived from the presented method.