Fuel cells hybrid systems for resilient microgrids

Nowadays, resilient grids meet growing interest for their capability of let survive critical load even in case of power fault coming from grid disturbance and disasters. In particular, telecommunications infrastructures (point-to-point and cell infrastructure) have distributed systems (RBS, DCs) equipped with storage devices used to guarantee continuous operation of the supplied equipment. Since high value services are provided to a wide set of customers, unexpected service unavailability is source of economic losses. This embedded UPS function, despite avoiding service interruption and contract penalties to the service providers, requires batteries whose unused capacity could be fruitfully exploited to provide the grid with valuable and paid energy services (frequency regulation - power and/or energy regulation in time slots - peak smoothing). For this reason, the supply systems of such plants, beside the internal energy storage devices, had better to have redundancy of energy sources (e.g. electrical grid and natural gas network) and tailored power flows control strategies to optimize the equipment utilization and costs, even in the case of external energy shortage. In this work, a combined approach with Fuel Cell (FC) and Fuzzy Logic (FL) is investigated to determine a good compromise between equipment installation, control logic, and availability of the service (downtime probability), even accounting for weather forecast, energy price and storage system exploitation (depth of discharge). For the implemented case studies of the simulation, a landline station located in Italy is analyzed by simulating different functions and power equipment to assess the benefits achievable the presented approach.