Optimal energy management of nanogrid using battery storage system

Abstract

This paper presents the optimal energy management approach with optimum sizing of the battery storage system (BSS) for the minimal possible total operating cost of the considered nanogrid. The five various operating modes are tested to achieve the optimal operating mode on an hourly basis. Linear programming (LP) is used to get optimal solutions for objective functions having non-integer variables whereas mixed-integer linear programming (MILP) is used to optimize the objective function having an integer variable. The proposed hourly-based optimal operating mode produces 17.8–94.5 % savings in the day operating cost compared to the best individual operating mode. The optimal capacity of the battery storage system is also derived by using the proposed operating modes. The achieved optimal capacity of BSS based on the day operating cost is further modified with the help of investment cost and its interest paid during the life span which suggests that the optimal capacity range will be 4–19 kWh for this nanogrid.