Why is adiabatic compressed air energy storage yet to become a viable energy storage option?

Daniel L Pottie,Philip Eames,Edward R Barbour

doi:10.1016/j.isci.2021.102440

Abstract

SummaryRecent theoretical studies have predicted that adiabatic compressed air energy storage (ACAES) can be an effective energy storage option in the future. However, major experimental projects and commercial ventures have so far failed to yield any viable prototypes. Here we explore the underlying reasons behind this failure. By developing an analytical idealized model of a typical ACAES design, we derive a design-dependent efficiency limit for a system with hypothetical, perfect components. This previously overlooked limit, equal to 93.6% under continuous cycling for a typical design, arises from irreversibility associated with the transient pressure in the system. Although the exact value is design dependent, the methodology we present for finding the limit is applicable for a wide range of designs. Turning to real systems, the limit alone does not fully explain the failure of practical ACAES research. However, reviewing the available evidence alongside our analytical model, we reason that underestimation of the system complexity, difficulty with the integration of off-the-shelf components, and a number of misleading performance claims are the primary reasons hindering ACAES development.

Highlights

Adiabatic compressed air energy storage (ACAES) is a concept for thermo-mechanical energy storage with the potential to offer low-cost, large-scale, and fossil-fuel-free operation
The heat at the compressor outlets is removed from the air via heat exchangers (HEX) and stored in separate thermal energy stores (TES) (Figure 1 point (2)), whereas the cool compressed air is stored in a high-pressure (HP) air store (Figure 1 point (3))
We demonstrate here that the efficiency limit of typical designs is considerably lower than 100%— for the design illustrated in Figure 2 we find a limit of 93.6%

Summary

Introduction

Adiabatic compressed air energy storage (ACAES) is a concept for thermo-mechanical energy storage with the potential to offer low-cost, large-scale, and fossil-fuel-free operation. Work is used to compress atmospheric air in compressors (Figure 1 point (1)), generating heat in the process. The heat at the compressor outlets is removed from the air via heat exchangers (HEX) and stored in separate thermal energy stores (TES) (Figure 1 point (2)), whereas the cool compressed air is stored in a high-pressure (HP) air store (Figure 1 point (3)). The cool compressed air is recombined with the heat from the TES to generate hot, high-pressure air (Figure 1 point (4)), which is expanded through turbines to generate work (Figure 1 point (5)).

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Discussion

Conclusion