Energy and economic performance assessment of the novel integration of an advanced configuration of liquid air energy storage plant with an existing large-scale natural gas combined cycle

Abstract

This article proposes the novel integration of an advanced configuration of Liquid Air Energy Storage (LAES) plant and an additional gas turbine cycle with an existing large-scale Natural Gas Combined Cycle (NGCC). A novel mode of exploiting the electric energy stored within the LAES plant and additional gas turbine cycle in combination with the existing NGCC is aimed at increasing its revenues in the electricity market. The energy performance analysis of the integrated plant at off-design conditions is carried out in presence of simultaneous changes of the pressure in the liquid air storage site (p3) and of the pressure at the outlet of the cryogenic pump in the discharging circuit (p25). The maximum storage efficiency is 2.173. The uncertainty economic analysis is performed in three alternative economic scenarios - expected, pessimistic and optimistic - in order to assess the profitability of the installation and operability of the integrated plant compared with the stand-alone NGCC. In the expected scenario, the integrated plant leads to profitability in the whole range of each p3 and p25, with the exception of the minimum value of p25. With varying p3 and p25, the profitability is always absent in the pessimistic scenario, whereas it is always present in the optimistic one. The proposed approach can be extended to the integration of an LAES plant with a generic existing large-scale thermal power plant in order to increase its revenues in the electricity market.