Sales for the Audi A3 Sportback g-tron started in Germany on February 13. Powered by a 1.4-liter TFSI engine producing 109 hp (110PS), the A3 G-Tron can run on natural gas, e-gas generated by Audi or gasoline.

Audi says the G-Tron is entirely CO2 neutral when running on e-gas. It is a synthetic methane produced at the Audi e-gas facility and the Audi e-gas is currently “the most environmentally friendly form of long-distance mobility”.

Audi’s e-gas is generated using green electricity, which binds as much CO2 as is released when the Audi A3 G-Tron is driven in gas mode. The vehicle consumes between 3.2 and 3.3 kg of gas per 100 km.

Audi e-gas is available at over 650 fuel stations in Germany.