A dynamic solid oxide fuel cell empowered by the built-in iron-bed solid fuel†
Large scale integration of intermittent solar and wind power can result in an imbalance in generation and load creating a stressed grid with increased frequency excursions and large power ramps. To mitigate these instabilities the use of energy storage devices such as batteries or other mechanical devices is under investigation. Solid oxide fuel cells (SOFCs) are a class of efficient and clean power generator that can provide a timely power injection into the grid. However, they have limited ramping capability and overload tolerance due to fuel delivery constraints that can cause fuel starvation, resulting in Ni-oxidation and irreversible degradation in performance. Herein, we demonstrate a new concept of SOFC that incorporates a regenerative Fe-bed inside the anode chamber as a means of boosting SOFC's dynamic response. The testing results show that such Fe-bed SOFC can operate at 195% overloaded power with a doubled power output over the baseload for at least 5 min, whereas the control Fe-bed free SOFC cannot operate even at 27% overload for 1 min. More interestingly, the Fe-SOFC can respond to load demand instantaneously, reaching a ramp rate of ±11 W cm−2 min−1. The demonstrated new functionality is expected to empower SOFCs to play a transformational role in providing fast ramping power to the utility grid and overload-tolerant baseload power to the critical data centres. The challenges of this new technology are also discussed.