A renewable sources-based smart grid using hydrogen as backup. Optimization criteria for the energy management

This paper presents a real smart grid for distributed generation based on renewable energy sources and with hydrogen as backup element. The smart grid can operate in isolation or connected to another grid. The hybrid smart grid consists on solar panels (PV) and wind turbine (WT) as primary energy sources. Apart from the own load to supply, an electrolyzer (ELEC) will act as secondary load to ensure the energy balance in situations of excess production. Additionally, there are backup elements like a batteries bank (BAT) that is used as primary backup energy, and a fuel cell system (FC) as secondary backup energy. Then, it is necessary the use of hydrogen backup technologies like metal hybrid (MH) tanks. The main characteristic of the smart grid is that it incorporates an energy management system (EMS) which takes into account technical and economic criteria to optimize the operation of each of the systems involved at time that it ensures the power balance within the entire system. The EMS is based on the hysteresis concept around the state of charge (SOC) of the BAT, and at the optimum operating points of the FC and ELEC. In addition, a hydrogen management strategy will be included to maximize the yield in its production, storage and consumption. This smart grid has been implemented physically, so its performance is tested and experimental results can demonstrate its feasibility.