Abstract
This study deals with a future power system with a high share of renewable generation. Volatile sources like wind and solar power require short-term balancing as well as seasonal balancing to meet the electricity demand. The focus of this study is the interaction between short-term storages (like pumped storage hydroelectricity and battery storages) with long-term storages (like seasonal hydro-storage and power-to-gas alternatives). The results of an optimisation system are presented, which show that additional long-term storages are no competitor to existing pumped hydro-storages. Instead the operating hours of short-term storages will increase.