Development of High Grade Heat Storage for integration with Liquid Air Energy Storage

"Energy storage is a vital aspect of electricity supply, balancing variation in energy demand and energy generation. A novel approach to energy storage uses refrigerated air to store energy until it is needed. Liquid Air Energy Storage (LAES) uses electricity to cool air to -196degC, the temperature at which it liquefies. The liquid is then stored in an insulated tank until there is a demand for the stored energy. Exposure to ambient air or waste heat from an industrial process causes rapid re-gasification of the refrigerated air and a 700-fold expansion in volume; this expansion is used to drive a turbine and generate electricity.

LAES brings considerable benefits to the grid in terms of security of supply. Its large scale, long duration storage capability helps balance the grid against variation in generation and demand, with intermittency linked to the increasing contribution of renewable energy, such as wind power, in the energy generation mix. A major advantage over conventional energy storage options is that LAES systems can be placed within industrial estates or next to existing power generators in order to capture waste heat which can be used to create the gas; thus increasing the efficiency of the system.

UK SME Highview Power Storage are world leaders in large scale, long duration LAES energy storage. Highview's LAES system, currently being commissioned in a demonstration plant in Pilsworth, Greater Manchester, has been designed to use off the shelf components, proven in other applications and with long lifespans (30 years), minimising technology risk. It also uses widely available and environmentally benign materials, such as gravel in the cold store. The demonstration plant uses a water based heat store; whilst this represents the current state-of-the-art, water has significant limitations and Highview, in partnership with the University of Brighton, are seeking Innovate UK support to develop an alternative, innovative HGHS that makes a significant contribution to LAES process efficiency. This project will optimise LAES technology and accelerate commercialisation.

Specifically, the project will develop a High Grade Heat Store Solution (HGHS) that allows Highview's LAES system to recover higher temperature waste heat from the process itself or from contributory sources that are co-located. An innovative approach is proposed, entailing the development of an alternative heat transfer fluid (HTF) that correlates with the pressure, heat transfer, viscosity, flammability and toxicity parameters of LAES, and operates at temperatures that deliver optimized RTE within a practical, cost-effective HGHS solution."