Optimal Operation of a Residential Microgrid: The Role of Demand Side Management

In this paper demand side management (DSM), characterized by shifting techniques, is applied to a residential microgrid. It is supposed that the microgrid is managed by a prosumer, a decision maker who manages distributed energy sources, storage units, ICT elements, and loads involved in the grid. DSM is considered as an integral part of the optimal economic short-term management problem such that the allocation of shiftable loads is treated as a variable must be determined simultaneously with all the others variables (i.e. energy exchange with the main grid, internal production, charge/discharge of electrical storage units). This paper focuses on the formulation of an economic model including functional links between shiftable and shifted loads properly linked. The objective function is the minimization of the operation energy costs. The model is implemented using IBM ILOG CPLEX an optimization programming language solver. The analysis shows how the variable allocation of shiftable loads is related to the other variables and how all the variables are linked (directly or indirectly) to the energy price and to the other parameters typical of shiftable energy devices. Moreover, the model allows to easily perform sensitivity analyses by varying the parameters considered. For instance, transitioning from the pre-shift to post-shift state, an improvement of the economic objective corresponds to an enhancement in the utility load profile. A sensitivity analysis is carried out by varying the maximum amount of power exchanged with the main grid. Results provide useful information to find a compromise between connecting interests. Numerical results are presented and discussed.