Physically 100 % renewable electricity supply through hybrid electricity storage – A top-down modelling study for the case of Austria

Abstract

A top-down model calculation based on real generation and demand data is presented for the hypothetical case of 100 % renewable electricity generation combined with hybrid electricity storage infrastructure in the Austrian control area (9 million inhabitants, electric demand ∼70 TWh per year). To reach 100 % physical coverage by renewables, the actual wind and photovoltaic generation curves in the selected reference year of 2022 were scaled by a factor of 2.8 and 30, respectively. In the scope of the presented system are lithium-ion battery storage (cyclic efficiency 90 %), pumped hydro storage (70 %) and power-to-gas storage with subsequent re-electrification in gas turbine combined cycle plants operated as combined heat and power (CHP) system (30 %). Our core aspect lies in the optimized operation of the hybrid storage system, where the charging and discharging of the storage technology with higher cyclic efficiency is given priority. A straightforward cascading control algorithm is applied with individual elements functioning as simple proportional controllers. The results show how a 100 % renewable electricity system in Austria could be configured, partially building upon existing electricity generation infrastructure (pumped hydro and gas turbine combined cycle plants) and on the implementation of new lithium-ion battery storage with a total capacity of 100 GWh and new electrolysis infrastructure with a power of 5 to 10 GW. To overcome existing limitations of the presented model, an extension to a more complex model with spatial differentiation and consideration of electricity grid characteristics and constraints is recommended.