Chemical looping electricity storage

Abstract

Developing grid-scale energy storage technologies is the key element for broader deployment of renewable sources of energy. This paper examines a simple cycle which makes use of a thermo-chemical store, with a view to achieving high storage capacity by using the chemical looping concept. Results show that a Chemical Looping Electricity Storage (CLES) system can achieve a very high capacity, in the range of 250–350 kWh/m3, second only to hydrogen electricity storage systems. Its round-trip efficiency (40–55%) is potentially higher than that of the hydrogen electricity storage systems. By achieving a higher capacity than pumped thermal energy storage and higher round-trip efficiency than that of hydrogen systems, CLES has the potential to fill out the gap between these two grid-scale storage technologies. Thus, this system may play an important role in our future energy mix because, unlike hydrogen storage, it can achieve a high storage capacity without a huge penalty on its round-trip efficiency.