Deductive assessment of a hybrid electricity storage system depending on varying renewable generation designs for Austria

Abstract

Carrying out a joint assessment of electricity storage and renewable generation expansion, the authors provide insights into synergies and interrelations following a holistic approach. Based upon actual generation and load profiles for the case of Austria, a 100 % renewable electricity system is analysed in tandem with a hybrid electricity storage system. The straightforward top-down simulation incorporates a lithium-ion battery, pumped hydro storage and power-to-gas storage, some of which were selected on the premise of leveraging existing infrastructure. An integral aspect of the chosen approach lies in the efficient operation of the hybrid storage system, where charging and discharging of the technology with highest cyclical efficiency is given preference. This approach minimizes energy losses and consequently increases the overall performance of the system. Five different scenarios with varying shares of wind and photovoltaic generation are presented, to provide a deeper understanding on the changing requirements on the hybrid electricity storage system. Additionally, the effect on the required renewable generation, due to the altered structure of the hybrid electricity storage system, is examined. Under the assumed system boundaries, the analysis reveals the highest system performance and most cost-efficient scenario characterized by a mixed share of 20 % photovoltaic, 44 % wind, 33 % run-of-river and 3 % biomass-based generation on the total annual generation (73.41 TWh). This scenario results in the lowest requirement of total annual generation as well as total charging (29.88 TWh) and discharging requirements ((-) 17.89 TWh) per year which are 43 % and 41 % lower compared to the least favourable scenario.