Renewable natural gas Renewable natural gas Renewable Natural Gas (RNG), also known as Sustainable Natural Gas (SNG) or biomethane, is a biogas which has been upgraded to a quality similar to fossil natural gas and having a methane concentration of 90% or greater. A biogas is a gaseous form of methane obtained from biomass. By upgrading the quality to that of natural gas, it becomes possible to distribute the gas to customers via the existing gas grid within existing appliances. Renewable natural gas is a subset of synthetic natural gas or substitute natural gas (SNG). Renewable natural gas can be produced and distributed
Liquefied natural gas Twomey received patents for a process for large scale liquefaction of natural gas. The intention was to store natural gas as a liquid so it could be used for shaving peak energy loads during cold snaps. Because of large volumes it is not practical to store natural gas, as a gas, near atmospheric pressure. However, if it can be liquefied it can be stored in a volume 600 times smaller. This is a practical way to store it but the gas must be stored at −260 °F (−162 °C). There are two processes for liquefying natural gas in large quantities.