Multi-energy liquid air energy storage: A novel solution for flexible operation of districts with thermal networks

Highlights: • Technical and district integration study of multi-energy liquid air energy storage. • Plant multi-energy capability maps are presented and discussed. • Multi-energy operation degrades electric efficiency but improves energy efficiency. • District operation is supported by reshaping electricity, heating and cooling load. • Multi-energy operation yields up to 12.6% cost saving. Liquid Air Energy Storage (LAES) stores electricity in the form of a liquid cryogen while making hot and cold streams available during charging and discharging processes. The combination of electricity, hot and cold makes LAES a promising asset for the management of multi-energy streams in various energy systems; however, such opportunity has not received attention so far. To overcome the traditional view of LAES as electricity storage only, this study investigates the techno-economic value of using LAES as a smart multi-energy asset for the provision of heat and cold, alongside power, in districts with heating and cooling networks. A reduced thermodynamic model of LAES was developed, validated and used to i) quantify the thermodynamic efficiency for a multi-energy LAES, ii) generalise the multi-energy capability of LAES over the three energy vectors considered iii) link different plant designs and integration conditions – in terms of loads and temperatures – with the associated multi-energy LAES performance and iv) describe multi-energy LAES operation as part of two district sizes, for provision of peak and base load. It is found that, by leveraging the vector-coupling capability of LAES, more flexible district operation can be achieved, with increased LAES energy efficiency from 47% to 72.8% and up to 8–12% reduction of operational costs, in the considered integration case studies. Results demonstrate the technical feasibility of multi-energy LAES operation and illustrate the associated trade-offs and potential: new perspectives for smart management of multi-energy systems are opened up.