Progress and prospects of thermo-mechanical energy storage—a critical review

Abstract The share of electricity generated by intermittent renewable energy sources is increasing (now at 26% global generation) and the requirements affordable, reliable secure supply designate grid-scale storage as an imperative component most transition pathways. widely deployed bulk solution pumped-hydro (PHES), however, this technology geographically constrained. Alternatively, flow batteries are location independent have higher densities than PHES, but remain associated with high costs short lifetimes, which highlights importance developing utilizing additional larger-scale, longer-duration long-lifetime alternatives. In paper, we review a class promising technologies based on thermo-mechanical principles, includes: compressed-air storage, liquid-air pumped-thermal storage. thermodynamic principles upon these (TMES) discussed synopsis recent progress in their development presented, assessing ability to provide cost-effective solutions. current performance future prospects TMES systems examined within unified framework thermo-economic analysis conducted explore competitiveness relative each other well when compared PHES battery systems. This includes carefully selected economic methodologies for estimating configuration order detailed fair comparison various system sizes. reveals that technical characteristics such that, especially discharge power ratings longer durations, they can offer (round-trip efficiencies 60%) along long lifetimes (>30 years), low specific (often below 100 $ kWh −1 ), ecological footprints unique sector-coupling features options. significant potential further comparisons paper be used benchmark evolution.