18th June 2025
“Shell believes natural gas and LNG have a critical role to play in the energy transition by producing less carbon emissions than coal when used to generate electricity, helping to maintain grid stability as the share of renewable energy grows, increasingly powering transport and shipping, and providing energy security in the coming decades.” (1)
Is LNG really a green fuel?
Liquid natural gas (LNG) is natural gas that has been made into a liquid so that it can be more readily transported. The liquefaction process involves cooling the gas to -161oC (-259F). The process reduces it to 1/600th of its original un-liquified volume and to half the weight of water. This reduction in volume has made the storage, and the shipping over significant distances, an economic option. It does of course have to be kept at the required supercool temperature throughout. It is only when it is going to fed into the domestic gas grid that is returned to its gaseous state by warming.
Before the liquefaction became a practicable option, natural gas was typically used by consumers in the locality – in the UK our gas came from the North Sea. Now gas can be sourced from across the world and can be stored whilst buyers are found. Significant amounts of this gas is shale gas using fracking processes. The United States is the world’s largest producer of LNG, followed by Australia and Qatar. Russia despite the fall in demand from European customers, is the fourth largest producer with large reserves of has in Siberia.
LNG is 85-95% methane and when it is burnt produces water and carbon dioxide. And the proportion of carbon dioxide produced is 40% less carbon dioxide (CO2) than coal and 30% less than oil (1) allowing LNG to be marketed as a green fuel. However methane is a more harmful greenhouse gas as when it is released into the atmosphere it a greater impact than carbon dioxide in increasing global temperatures.
However the extraction process, especially by fracking, and leakage during the liquefaction and transportation process, gives rise to substantial leakage of methane. A report produced for the Society of Chemical Industry concluded that 66% of greenhouse gas emissions from LNG were released during these stages with only 34% released during the end-use combustion.(2)
The Green Tau 