New parametric performance maps for a novel sizing and selection methodology of a Liquid Air Energy Storage system

Abstract

Liquid Air Energy Storage is one of the most promising novel energy storage concept that guarantees at the same time viable capital cost, high energy density and no geographical/geological constrains. Considering the complexity of the plant, composed by three different phases (charge, discharge and storage), thermodynamic modelling could be a challenging undertaking. Making use of the strong similitude with gas turbine technology, this paper aims to deliver new generalized performance maps for Liquid Air Energy Storage system. The performance maps, validated against the experimental results of Highview Power pilot plant, have been modelled by means of a comprehensive sensitivity analysis carried out considering three macro-scenarios imposing the storage pressures and the turbomachinery performance (design/off-design conditions). By means of the performance maps, the impact of the main LAES operative parameters, as well as the effect of the cold/warm thermal energy storage utilization factor, over the key performance indicators has been assessed and analysed. The analysis shows that at design condition the higher is the value of the high grade cold thermal energy storage utilization factor, the lower is the positive impact of charge pressure over the specific consumption. For off-design condition of the main turbomachinery, the negative effect of lower isentropic efficiency of the main turbomachinery on the round trip efficiency is amplified by the choice of the charge pressure. At high value of the warm energy storage utilization factor, this negative effect can be partially offset by the higher Turbine Inlet Temperature available for the expansion process of the discharge phase.