Enhancing Battery Energy Storage in the Finnish FCR-N Market with Flywheel Technology

Abstract

Abstract The integration of flywheel technology with battery energy storage systems presents a promising strategy to improve both the operational lifetime and economic viability of energy storage solutions for providing ancillary services. In this study, mixed integer linear programming optimisation modeling is employed to investigate the benefits of combining batteries with flywheels in the context of the Finnish FCR-N market. Different flywheel:battery capacity ratios are considered to investigate the optimal ratio. Furthermore, the impact of grid frequency and battery degradation is taken into account. The results reveal that battery degradation has little impact on the optimal dispatch of a hybrid system. Highlighting the robustness of the flywheel-battery combination in mitigating battery degradation during ancillary services provision. The findings demonstrate that integrating flywheels into battery systems can extend the operational lifetime or reduce operational cost of the battery through removing the burden of small cycles from the battery. Specifically, a hybrid system with a flywheel-to-battery capacity ratio of 0.2 is recommended, exhibiting a notable 2.7-fold extension of battery lifetime as well as being less strongly impacted by different grid frequency scenarios than higher capacity ratios. Moreover, the incorporation of flywheels unlocks diverse business opportunities, enhancing the overall economic value of the energy storage assets.