Electricity Storage With a Solid Bed High Temperature Thermal Energy Storage System (HTTES) - A Methodical Approach to Improve the Pumped Thermal Grid Storage Concept

High Temperature Thermal Energy Storage (HTTES) systems offer a wide range of possible applications. Since electrical batteries such as Li-ion batteries suffer degradation and since complete battery-systems are expected not to fall to low cost levels (IEA-WEO report 2018 [1]) until 2040, it becomes economically more interesting to use thermal energy storage systems as 'Thermal Batteries' to store electrical energy. In this article an improved and optimized Thermal battery based on a closed Brayton-cycle is proposed (Carnotbattery). The improved electricity storage concept applies an efficient low-cost high temperature thermal energy storage technology for both, the hot- and the cold thermal storage. This concept not only allows for a bigger temperature spread and simplified operation, but also reduces CAPEX significantly. It is named enolcon-OPTES-Battery (Optimized Pumped Thermal Energy Storage - Battery).