Thermoeconomic analysis of a novel liquefied biomethane-air energy storage system

Bio-methane demonstrates dual regulatory advantages in smart energy networks. It enhances gas supply flexibility through pipeline pressure balancing while serving as a cold energy carrier for power peaking. However, the current research on bio-methane energy storage and peak shifting remains in the exploratory stage. A novel liquefied biomethane-air combined energy storage (LBAES) system is proposed to overcome the low output coefficient of liquefied air energy storage system and operational inflexibility of liquefied biomethane energy storage system. To evaluate the feasibility of the proposed system, a thermoeconomic analysis considering energy, exergy, and economic evaluations was carried out. Sensitivity analysis and multi-objective optimization were performed to identify optimal operating parameters. Results indicate that the maximum round-trip efficiency achieves 88.04 % after multi-objective optimization, at which point the net present value is $539,351.81. The exergy efficiency of system is 56.30 %. Heat exchangers (HE1, HE2, HE6, and HE8) account for 64.70 % of the total exergy loss. The proposed system improves the flexibility of the power system for peaking, which effectively enables the realization of the dual-peaking function of gas and electricity in the biogas project.