Energy and economic analysis of natural gas storage methods: insights into liquefied, compressed and solidified forms

The efficient storage of methane is a critical factor in meeting the growing global energy demand and ensuring energy security. LNG and CNG are the most commonly used storage methods for natural gas. Some countries across the world are also practising the underground natural gas storage method (UNGS). SNG (Solidified natural gas) is another promising technology to store the natural gas. This study conducts a comprehensive energy and economic analysis of various methane storage technologies, including underground gas storage (UNGS), compressed natural gas (CNG), liquefied natural gas (LNG), and solidified natural gas (SNG) utilizing hydrates. Specific energy consumption, energy density, and total costs were the key performance metrics evaluated. Results highlight that while CNG and UNGS demonstrate the lowest energy consumption, LNG offers the highest volumetric energy density (up to 17.1 GJ/m3), with SNG presenting a safer alternative with moderate costs. SNG achieves storage through hydrate formation under moderate conditions (35-100 bar, 274-287 K), but energy demands for compression and cooling remain significant. The techno-economic analysis reveals that CNG has the lowest total costs (0.175 $/kg), while LNG exhibits significant cost variability ($0.169-0.434/kg) due to diverse process technologies. SNG's cost-effectiveness is competitive with lower-end LNG and UNGS values (0.184 $/kg), especially considering its safety and environmental advantages. The findings support the tailored application of storage methods based on priorities like safety, geographical feasibility, and energy efficiency.