Fuel Cells Hybrid Systems For Resilient Microgrids

Nowadays, resilient grids meet growing interest for their capability of supplying critical load even in case of power fault coming from grid disturbance and disasters. To do this, such grids involve redundant apparatus and predictive control schemes. For high value services, unexpected system unavailability is source of economic losses to the providers. Hence, beside the internal energy storage devices, such plants had better to have redundancy of energy sources (e.g. electrical grid and natural gas network) and tailored power flows control strategies still valid even in the case of external energy shortage. In this work, a supply system was developed both matching the requirements (both DC and AC) of the served ICT equipment, and capable of offering grid services as an experimental prosumer site. As fundamental design targets, energy conversion efficiency and cost reduction were addressed by developing a hybrid fuel cell/battery (SOFC/SNC) based prototype, and optimizing the size of each used device. Starting from field tests measurements, the hybrid generator was analyzed in a resilient grid scenario. Then, digital simulations compared different battery management algorithms and assessed the trade-off between battery exploitation and system resiliency against grid or gas network fault. The prototype showed satisfactory performance both for resilient microgrids and applications in which the continuous availability is a critical point (e.g. ICT equipment and data centers).