Substitute natural gas, or SNG, can be produced from fossil fuels such as lignite coal or from biofuels, when it is named Bio-SNG.
In the Great Plains, USA, approximately 15 TWh/year of SNG from lignite coal is injected into the national gas grid. The production process of SNG at the Great Plains plant involves gasification, gas cleaning, shift and methanation.
It is advantageous to distribute SNG and bio-SNG together with natural gas in a gas grid. In this way, the production of renewable gas can be phased in at the same rate as the production capacity is increased. The gas market and infrastructure the natural gas has contributed with is a condition for large scale introduction of renewable biomethane produced through anaerobic digestion (biogas) or gasification and methanation Bio-SNG.