The carbon dioxide removal potential of Liquid Air Energy Storage: A high-level technical and economic appraisal

Liquid Air Energy Storage (LAES) is at pilot scale. Air cooling and liquefaction stores energy; reheating revaporises the air at pressure, powering a turbine or engine (Ameel et al., 2013). Liquefaction requires water & CO2 removal, preventing ice fouling. This paper proposes subsequent geological storage of this CO2 - offering a novel Carbon Dioxide Removal (CDR) by-product, for the energy storage industry. It additionally assesses the scale constraint and economic opportunity offered by imple- menting this CDR approach. Similarly, established Com- pressed Air Energy Storage (CAES) uses air compression and subsequent expansion. CAES could also add CO2scrubbing and subsequent storage, at extra cost. CAES stores fewer joules per kilogram of air than LAES - potentially scrubbing more CO2 per joule stored. Opera- tional LAES/CAES technologies cannot offer full-scale CDR this century (Stocker et al., 2014), yet they could offer around 4% of projected CO2 disposals for LAES and < 25% for current-technology CAES. LAES CDR could reach trillion-dollar scale this century (20 billion USD/year, to first order). A larger, less certain commercial CDR opportunity exists for modified conventional CAES, due to additional equipment requirements. CDR may be commercially critical for LAES/CAES usage growth, and the necessary infrastructure may influence plant scaling and placement. A suggested design for low-pressure CAES theoretically offers global-scale CDR potential within a century (ignoring siting constraints) - but this must be costed against competing CDR and energy storage technologies