Substitute natural gas

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Substitute natural gas (SNG), or synthetic natural gas, is a fuel gas (predominantly methane, CH₄) that can be produced from fossil fuels such as lignite coal, oil shale, or from biofuels (when it is named bio-SNG) or using electricity with power-to-gas systems.

SNG in the form of LNG or CNG can be used in road, rail, air and marine transport vehicles as a substitute for costly diesel, petrol, etc. The carbon footprint of SNG derived from coal is comparable to petroleum products. Bio-SNG has a much smaller carbon footprint when compared to petroleum products. LPG can also be produced by synthesising SNG with partial reverse hydrogenation at high pressure and low temperature. LPG is more easily transportable than SNG, more suitable as fuel in two-wheeler or smaller HP vehicles/engines, and also fetches higher price in international market due to short supply.

Renewable electrical energy can also be used to create SNG (methane) via for example electrolysis of water or via a PEM fuel cell in reverse to create hydrogen which is then reacted with CO₂ from for example, CSS/U Utilisation in the Sabatier reaction.

CO₂ + 4H₂ → CH₄ + 2H₂O