Application of Liquid-Air and Pumped-Thermal Electricity Storage Systems in Low-Carbon Electricity Systems

Abstract

In this study, we consider two medium- to large-scale electricity storage systems currently under development, namely ‘Liquid-Air Energy Storage’ (LAES) and ‘Pumped-Thermal Electricity Storage’ (PTES). Consistent thermodynamic models and costing methodologies for the two systems are presented, with the objective of integrating the characteristics of these technologies into a whole-electricity system assessment model, and assessing their system-level value in different scenarios for power system decarbonisation. It is found that the value of storage varies greatly depending on the cumulative installed capacity of storage in the electrical system, with the storage technologies providing greater marginal benefits at low penetrations. Two carbon target scenarios showed similar results, with a limited effect of the carbon target on the system value of storage (although it is noted that this may change for even more ambitious carbon targets). On the other hand, the location and installed capacity of storage plants is found to have a significant impact on the system value and acceptable cost of these technologies. The whole-system value of PTES was found to be slightly higher than that of LAES, driven by a higher storage duration and efficiency, however, due to the higher power capital cost of PTES, this becomes less attractive for implementation at lower volumes than LAES.