Liquefied natural gas (LNG) is regarded as one of the cleanest fossil fuel and has experienced significant developments in recent years. The liquefaction process of natural gas is energy-intensive

while the regasification of LNG gives out a huge amount of waste energy since plenty of high grade cold energy (-160℃) from LNG is released to sea water directly in most cases

and also sometimes LNG is burned for regasification. On the other hand

liquid air energy storage (LAES) is an emerging energy storage technology for applications such as peak load shifting of power grids

which generates 30%-40% of compression heat (~200℃). Such heat could lead to energy waste if not recovered and used. The recovery of the compression heat is technically feasible but requires additional capital investment

which may not always be economically attractive. Therefore

we propose a power plant for recovering the waste cryogenic energy from LNG regasification and compression heat from the LAES. The challenge for such a power plant is the wide working temperature range between the low-temperature exergy source (-160℃) and heat source (~200℃). Nitrogen and argon are proposed as the working fluids to address the challenge. Thermodynamic analyses are carried out and the results show that the power plant could achieve a thermal efficiency of 27% and 19% and an exergy efficiency of 40% and 28% for nitrogen and argon

respectively. Here

with the nitrogen as working fluid undergoes a complete Brayton Cycle

while the argon based power plant goes through a combined Brayton and Rankine Cycle. Besides

the economic analysis shows that the payback period of this proposed system is only 2.2 years

utilizing the excess heat from a 5 MW/40MWh LAES system. The findings suggest that the waste energy based power plant could be co-located with the LNG terminal and LAES plant

providing additional power output and reducing energy waste.