Economic optimisation for a building with an integrated micro-grid connected to the national grid

This paper proposes a novel operating cost optimisation method for a building with an integrated micro-grid (MG) connected to the National Power Grid (NPG). The MG consists of a photovoltaic system (PVS) and a lead-acid battery bank (BB). The optimisation utilised a twenty-four hour forecast of building energy consumption and the corresponding electrical prices from the NPG. A piecemeal decision algorithm (PDA) and a particle swarm optimisation (PSO) algorithm were used to generate a charge/discharge rates schedule for the BB. The building energy consumption model was developed using empirical data and employee work schedules. Electricity prices were predicted using a real time pricing (RTP) model based on data from the single electricity market operator (SEM-O)[1]. The PVS and BB were modelled based on specifications from manufacturers, and weather data from the Cork Institute of Technology (CIT). The simulation results demonstrate that the building operating costs can be reduced by up to 23 % per day for a single charge/discharge rates schedule, or by up to 30 % per day for a multiple charge/discharge rates schedule.