Field Experience from Li-Ion BESS Delivering Primary Frequency Regulation in the Danish Energy Market

In this paper it is presented the practical experience from operating a 1.6 MW/ 0.4 MWh lithium ion battery energy storage system, which is providing primary frequency regulation service on the Danish energy market. Aspects of the battery system requirements and the used control strategy for primary frequency regulation service are discussed. Moreover, the estimation of the battery storage system lifetime is discussed based on the results from 1.5 years periodic inspections and measured performance degradation of the both BESSs.