University of Birmingham Researchers discover how to enhance the round trip efficiency of Liquid Air Energy Storage

A team of researchers at the Birmingham Energy Institute have developed a new technique which will improve the efficiency and commercial competitiveness of Liquid Air Energy Storage (LAES).

The team, led by Professor Yulong Ding, Director of the Birmingham Centre for Energy Storage, found a way to increase the round trip efficiency of LAES by 9-12 % compared to current LAES systems.

Significant efficiency gains were achieved by utilising the excess heat generated when air is converted to liquefied gas to generate additional electricity whilst the energy efficiency of the discharge process was also improved, in which liquefied air is converted back into a gas to power an electricity-producing turbine. 

An economic analysis calculated on a project lifespan of 15 years suggested that the combination of the two techniques will provide a payback period of less than ~ 3 years. 

When asked about his thoughts on this new discovery, Professor Yulong Ding explained: "I am extremely pleased with the findings. This represents a significant step in improving the commercial competitiveness of liquid air energy storage - a technology invented by my team some 12 years ago."

LAES, otherwise known as Cryogenic Energy Storage (CES), helps improve how we generate, deliver and consume electricity. It allows us excess electricity available at off-peak times to be used to create and store liquefied air. This air can then be released in the future to generate electricity at times of peak demand. As the proportion of electricity generated by renewable energy sources increases, energy storage technologies will have an ever more important role to play in regulating power supplies.

LAES was first developed by  the University of Birmingham's first Chamberlain Chair, Professor Yulong Ding, and his team 12 years ago. The technology draws ambient air from the environment before cleansing, compressing and liquefying it to sub-zero temperatures. The liquid air is then stored for extended periods of time. When more electricity is required, the liquid air is drawn from the tanks, pumped to a high pressure and heated to produce a high-pressure gas. This high-pressure gas is then used to spin a turbine which drives a generator to produce electricity. 

 The team's work is published in the Applied Energy journal.