Integration of liquid air energy storage into the spanish power grid

The European energy transition implies a relevant increase of renewable energies in the electric power generation mix. Integrating additional renewables is becoming more challenging due to their variability. Spain's peninsular situation aggravates this problem because it is an electric island. Within this framework, Liquid Air Energy Storage (LAES) is a promising technology for balancing the power grid. This work proposes a transient thermodynamic modelling of a 100 MW LAES plant. The cycle incorporates a packed-bed cold-storage system to enhance the charge/discharge efficiency. The appearance of a thermocline in the cold-storage unit is relevant regarding the round-trip efficiency. An economic study based on the simulation results is performed considering different scenarios of renewables grid penetration (photovoltaic and wind power). Depending on the installed LAES capacity, the levelized cost of delivered energy is evaluated. The results suggest that it is more interesting to store photovoltaic energy in the daytime peak hours and release energy during the night-time valleys to maximize the use of storage plants. This allows the levelized cost of energy and storage to be reduced to values as low as 150 and 50 (sic)/MWh respectively. These prices are competitive with compressed air energy storage and even with pumped-hydro storage. (C) 2019 Elsevier Ltd. All rights reserved.