Modelling and optimization of a flexible hydrogen-fueled pressurized PEMFC power plant for grid balancing purposes

In a scenario characterized by an increasing penetration of non-dispatchable renewable energy sources and the need of fast-ramping grid-balancing power plants, the EU project GRASSHOPPER aims to setup and demonstrate a highly flexible PEMFC Power Plant, hydrogen fueled and scalable to MW-size, designed to provide grid support. In this work, different layouts proposed for the innovative MW-scale plant are simulated to optimize design and off-design operation. The simulation model details the main BoP components performances and includes a customized PEMFC model, validated through dedicated experiments. The system may operate at atmospheric or mild pressurized conditions: pressurization to 0.7 barg allows significantly higher net system efficiency, despite the increasing BoP consumptions. The additional energy recovery from the cathode exhaust with an expander gives higher net power and net efficiency, adding up to 2%pt and reaching values between 47%LHV and 55%LHV for currents between 100% and 20% of the nominal value.