Battery Energy Storage System Lifetime prediction for Grid-Booster Applications

Grid boosters are an elegant option to reduce the grid expansion needed for the energy transition by optimizing it. This study examines how battery grid boosters can be designed more economically and seeks to predict their lifespan for different design variants. In the context of this work, calendar and cycling aging models for battery degradation are applied to the special application of a battery energy storage system, used as a grid booster. The difference to conventional battery systems is the small number of cycles in its lifetime. So smaller capacity degradation is assumed. The calculations predict a lifetime of 25 years, for a grid booster, compared to 15 to 20 years of a conventional system. So already a longer lifespan, as the needed 23 years for amortization, can be reached. The calculations show that by using a lower state of charge and a lower storage temperature in the idle times, the lifespan can be extended and so an increase of economic efficiency can be realized. To aim for a higher return on invest, a dual-use approach is discussed. Through the trade-off between more cycles and lifetime, economic viability can be achieved after 16 years.