Research advances use of liquid air for energy storage

Developed by University of Birmingham academics, liquid air energy storage could play a part in helping to crack the global challenge faced by electricity providers of balancing power supply and demand – thanks to a major research project.

Led by energy experts at the University of Birmingham, MANIFEST (Multi-Scale Analysis for Facilities for Energy Storage) is a £5 million project that taps into Birmingham’s long-standing expertise in cryogenic and thermal energy storage.

The programme investigates how we can further improve energy storage technologies through integration and explore potential application scenarios with an aim to accelerate the deployment of the storage technologies.

MANIFEST addresses a number of research questions about how materials are better used in energy storage devices, how storage technologies can be better integrated and how integrated energy storage devices can be best optimised in the energy system.

The project, led by Dr Jonathan Radcliffe, brings together Birmingham’s expertise in liquid air and thermal energy storage with scientists from across the country working on thermo-mechanical and electrochemical storage technologies and their integration and optimisation.

Professor Yulong Ding, from the University of Birmingham and one of the originators of liquid air energy storage, is leading on multiscale modelling of energy storage systems in MANIFEST.

Professor Ding commented: “Modelling energy storage systems is extremely complex and challenging, the MANIFEST programme provided cross-university and cross-discipline collaborations for addressing the challenge. Equally important and also of our particular interest is experimental validation of multiscale modelling through this research programme.

“Technologies such as liquid air and thermal energy storage have a great potential to help crack the energy conundrum: how can variable generation from renewables meet the needs of energy users. We have one of the world’s first experimental cryogenic energy storage facilities on campus and also achieved success with the first commercially available shipping container constructed from cold storage materials that can be charged with cold energy.”

Additionally, the University of Birmingham is leading on establishing UKESTO (UK Energy Storage Observatory) as part of the MANIFEST project – creating a national ‘observatory’ for energy storage that will give scientists online access to data from experimental facilities at the partner universities within the consortium.

MANIFEST and UKESTO lead Dr. Jonathan Radcliffe, Reader in Energy Systems and Innovation, commented: “MANIFEST is allowing the detailed study of a range of energy storage technologies and their potential impact across the energy system. There is a focus on batteries now, but that is just part of what will be required to integrate renewables at the scale needed to be on track for net-zero.  And whilst there is a growing number of energy storage demonstrator sites in the UK and globally, there is little data available on their operations.

“UKESTO will connect energy storage pilot plants on university campuses to create a network of national facilities that establish the UK as an innovation hub - allowing systematic study of energy storage technologies to an extent that is not possible with industrial demonstrators.”

The observatory makes use of the UK Energy Research Centre’s Energy Data Centre, a well-established national data repository.

Professor Ding and Professor Toby Peters, Professor of Cold Economy at the University of Birmingham, are widely recognised as the ‘founding fathers’ of liquid air energy storage, having identified both the need for large-scale energy, long duration storage back in 2004 and the potential to integrate mature components from existing industries in a new system able to scale to hundreds of MWs.

Working together Professor Ding led the team which invented and proved the idea of cold recycle, key to achieving high-levels of efficiency and Professor Peters mainstreamed the concept of liquid air as an energy storage solution vector for both electricity grids and clean cold and power.

Air’s main component gases liquefy at ~-196°C and the result occupies a 700th of the volume of those gases at room temperature. When liquid air is warmed and allowed to expand, its forceful expansion can spin turbines - operating generators and recovering part of the electricity used for liquefication.

Professor Peters said: “Liquid air energy storage is a unique solution to provide low-cost, large-scale long duration energy storage with no geographical constraints.  It also can harness waste heat or waste cold in the system to further increase the overall efficiency.

“With the demand now for large-scale, long duration energy storage, liquid air can emerge as the serious competitor to lithium-ion in grid-scale-storage.”