Audi's g-trons hit the market

© AudiThe g-trons won't allow you to switch to petrol as long as you have CNG onboard

Different as they may seem, both cars are underpinned by the same technology, including the 2-litre TFSI engine, good for 170 PS of power and 270 Nm of torque. It can run on petrol, fossil natural gas or Audi's synthetic methane, called e-gas. In fact, it's not that you can buy pure e-gas and refill your tanks with it – instead Audi will pump an appropriate amount into the grid for you when you refuel at a regular CNG station. This way a g-tron emits some CO₂ from the tailpipe, but the amount is offset by the carbon-negative e-gas fuel.

According to Audi, both cars can cover up to 500 km in methane mode without refueling, plus an additional 450 km on petrol. CNG tanks are lightweight, made of CFRP and GFRP (carbon and glass fibre reinforced plastic) and can store up to 19 kg of fuel compressed to 200 bar. Boot capacity is somewhat compromised (the tanks are mounted underneath the trunks, in the underbody), but stands at 415 l in the A4 and 390 l in the A5, which is still decent enough. Top speeds in excess of 220 km/h for either of the cars seem satisfactory, too.

What about the prices, then? In their home market of Germany, where approx. 900 CNG refueling stations are in operation, the A4 Avant g-tron and the A5 Sportback g-tron are available for 40300 and 40800 euros, respectively. Other markets are scheduled to follow soon, after Audi showcases the g-tron technology in detail during the Frankfurt Motor Show in September 2017. Stay tuned!