Optimal design of multi-energy grid systems Finance a by: Hikmet Eliyev Optimal design of multi-energy systems with seasonal storage

System description and formulation of the optimization problem

The multi-energy system discussed in this study has the primary goal of providing the energy required by a specific user. MES is connected to gas and electric networks and includes a set of conversion technologies, both traditional and based on renewable energy sources, as well as storage units. In fig. 1 schematically shows such a system. Weather conditions, electricity and gas prices, as well as energy demand profiles are three sets of input data for the optimization problem. The model returns the optimal design of the system in terms of the choice of technology and size, as well as the optimal operation of the installed units. The problem is mathematically formulated as MILP, where binary variables are introduced to simulate the performance of conversion units and the capital costs of the technologies being studied. MILP can be written in a general way so that c and d represent the cost vectors associated with continuous and binary decision variables, x and y, respectively; A and B are the corresponding constraint matrices, and b is the well-known term of constraint; and indicate the dimensions x and y, respectively. Further, the optimization problem is described in detail in terms of input data, solution variables, constraints, and objective function.