A study of different loss of life based calculations on batteries operating in enhanced frequency response

National Grid are investigating battery energy storage as a solution to help with energy balancing for frequency control. They are currently looking at Enhanced Frequency Response (EFR) as a solution, but, are unlikely to adapt this directly as they investigate new, more open, market strategies. Battery Energy Storage is still an expensive asset and the opportunity to use a hybrid scheme (with new and second life batteries) offers a potential lower cost solution. Determining the life cycle of a battery energy storage system is complex, as this is a combination of several processes including cyclic and calendric aging. Determining life cycles of a hybrid system is even more complex. This paper discusses different ways of determining life span published in literature and uses a model based case study approach using National Grid published data on frequency and EFR envelopes to investigate the different range of theoretical loss of life within different battery system.