Audi's new e-gas plant that produces CO2-neutral gas from renewable electricity has been working alongside the carmaker to create a gas-powered A3 that will make its public debut at the Geneva Motor Show. The A3 Sportback g-tron's powertrain consists of two gas tanks and a 1.4-liter TFSI unit rated at 108 horsepower and 147 pound-feet of torque. The tanks, stored under floor of the boot, can either store the Audi-produced e-gas or regular Compressed Natural Gas (CNG).

Audi claims fuel consumption on gas alone is 108 mpg (US avg.) with the g-tron offering a 249-mile range. A further 559 miles is provided by the gasoline engine. The tanks can each hold 7kg of gas, at a maximum 200 bar pressure, and when full weigh 27 kg less than a conventional fuel tank. An electronic pressure regulator allows for the combustion of low-pressure gas when driving at low speeds, and allows it to flow at high pressure when more performance is needed. Audi claims the g-tron is bivalent, meaning that performance is identical with either type of fuel. 0-62 is quoted at 11 seconds and top speed at 118.

The e-gas facility in Werlte uses renewable electricity to produce gas via the electrolysis of water, which makes hydrogen and oxygen. The reaction of the hydrogen with CO2 produces synthetic methane - or e-gas - that is chemically identical to natural gas. Audi's e-gas will be used to power 1500 A3 g-trons for trials that will see the cars cover over 9,300 miles in a year. Including the emissions created in the construction of the e-gas plant, Audi claims CO2 emissions are still less than 30 g/km.