Novel ASU–LAES system with flexible energy release: Analysis of cycle performance, economics, and peak shaving advantages

Abstract

This study uses a cryogenic distillation method air separation unit (ASU) coupled with liquid air energy storage (LAES) to improve the round-trip efficiency and reduce the initial investment of LAES. We propose an integrated system (ASU–LAES–DER) with different ways of energy release. In the novel system, the liquid air can be reheated and expanded to produce additional power, or the liquid air energy stream and part of the material stream can be used for ASU distillation to produce power saving effects. This novel integration allows the ASU to have load regulation capability and facilitates the implementation of demand-side power management. Furthermore, the flexible and efficient energy release methods improve the energy efficiency and economic value of LAES. The comprehensive round-trip efficiency of the system can reach 52.1%–69.2 % with a payback period of 3.25–6.72 years. The peaking index is used to analyze the peak-to-valley load transfer capability of the novel system. Results show that the peaking index ranges from 25.5 MW to 50.1 MW at different scales, indicating that the system can be used as an important grid peaking unit when applied on a large scale.