You may have heard by now that Audi has managed to make a carbon-neutral fuel out of water and carbon dioxide pulled from the air. This is all well and good, but will it work in your car? Nope, but don’t worry, Audi has a solution for that: the A4 G-Tron. The somewhat unfortunately named concept was just unveiled at the Frankfurt Auto Show, and is perhaps most remarkable for being fairly unremarkable. It is basically just a 2016 Audi A4 Avant (wagon) with a dual fuel system, and even this system isn’t too radically different from existing systems that have been in use for years.

It is perhaps not even right to call this a concept, since the G-Tron won’t look any different from other A4s when it hits dealerships in about a year’s time, minus the big decals on the sides, of course. You might be thinking that a year from now is awfully soon for a car that runs on some kind of half-magical new kind of fuel for which there is basically no infrastructure yet. But the G-Tron will also run on natural gas, and regular pump gas as well, giving you more choices for fuel than you ever knew you wanted.

Continue reading to learn more about the Audi A4 g-tron.


2016 Audi A4 G-Tron Exterior AutoShow
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2016 Audi A4 G-Tron Exterior AutoShow
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2016 Audi A4 G-Tron Exterior AutoShow
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The bodywork of the A4 G-Tron is no different from that of the current A4 Avant. Like all of its competitors as well, the A4 is thoroughly mainstream, unoffensive to the point of being somewhat bland. It is an attractive vehicle though, much more so than the vehicles that serve the same purpose but are in lower price brackets. There will actually be a new A4 for the 2017 model year, which the G-Tron will no doubt be based on.


2016 - 2018 Audi A4 High Resolution Interior
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Note: Standard 2016 Audi A4 interior shown.

The interior is again no different from the regular A4, but it is worth discussing because here there is a big change from the current model and the 2017 car. The current interior is nice, but the 2017 car will be greatly improved. Gone are many of the fidgety buttons that cluttered up the center stack, with most of these being integrated into the MMI infotainment system. The cabin is now dominated by horizontal lines that give a far more modern and less claustrophobic feel to the car. The MMI screen is bigger, and the gauge cluster has been replaced with one big screen. Not having to find homes for nearly as many buttons and knobs clearly freed up the designers to make a better interior.


2016 Audi A4 G-Tron Drawings Drivetrain
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This is where the big difference is between the G-Tron and the regular A4. The engine actually remains the same 2.0 TFSI mated to a seven-speed dual-clutch transmission that you’d find in other base A4s. But the fuel system is vastly different. There is still a tank for gasoline, but there are now two additional high pressure tanks for holding either natural gas or Audi’s e-gas.

The engine actually remains the same 2.0 TFSI mated to a seven-speed, dual-clutch transmission that you'd find in other base A4s. But the fuel system is vastly different.

The tanks hold a combined 41.9 pounds of gas at 200 bar of pressure. When these run out, the system automatically switches to gasoline. The natural gas/e-gas being more efficient, it is given priority by the system, with the gasoline acting as a backup, not unlike how a plug-in hybrid uses up its battery charge before switching on the gasoline engine.

This kind of system has been retrofitted to quite a few cars over the years for use with natural gas, and some fleet vehicles even come from the manufacturer already equipped with them. Taxis, for example have used them a long time. Audi’s version has obviously been updated, not only to use e-gas, but also to trim a bit of the weight off of the heavy metal tanks that are currently used.

Audi’s tanks are therefore a mix of fiberglass and carbon fiber, and the 2017 A4 will be 265 pounds lighter than the current model anyway. The tanks are also a bit smaller, but the A4 will still have a 310-mile range on natural gas. The downside of dual fuel, and this is true of Audi’s system as well, is that natural gas doesn’t produce as much power as gasoline in the same engine, and the G-Tron is rated at just 170 horsepower, down from the 190 horsepower rating that the engine gets with gasoline.


The current Audi A4 has been given an excellent crash test rating by the NHTSA, five stars in every category. The 2017 car will have to be tested again, but it uses the same platform and a similar body, so it’s very likely to get the same rating. But adding to this, the 2017 car will have a number of semi-autonomous systems designed for safety.

These include the usual blindspot warning and lane keeping systems, as well as an active cruise control that can handle heavy traffic at speeds below 40mph and will even stop and start the car during stop-and-go conditions. There is a pre-collision system that can jab the brakes at higher speeds if you come up on another car too fast, and will take over braking completely at speed under 52 mph. The navigation system will now give warnings about changing speed limits and upcoming intersections.


2016 Audi A4 G-Tron Exterior AutoShow
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Audi hasn’t released any pricing information for the G-Tron, and with a new A4 on the way, the pricing for the entire line is theoretically in flux. But it’s unlikely that it will change much from the current starting price of $36,000. The G-Tron will definitely be more, but the question is by how much? Audi will also be bringing out a plug-in hybrid version of the car (not at all confusingly called the “A4 E-Tron”) and the big question will be whether or not the G-Tron is priced the same as the hybrid or if the G-Tron will slot in between the regular 2.0 TFSI A4 and the hybrid. Carbon-fiber tanks can’t be cheap, but batteries certainly aren’t either. A fully loaded A4 will currently set you back in the neighborhood of $45,000. A hybrid will easily push past $50,000, but it’s difficult to imagine the G-Tron going any higher than that.


2016 Lexus ES Hybrid

2016 Lexus ES High Resolution Exterior
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Since the only cars using e-gas will be other Audis, the G-Tron’s big competition comes from the luxury hybrids that are already available. Lexus makes hybrid versions of several of its cars, but the pricing on the G-Tron is probably going to be most in line with that of the ES. Like the A4, the ES has quite a nice interior, but the Audi has it beat when it comes to handling, and Audi’s infotainment system is far less confusing than what you’ll find in a Lexus.

You can read more about the 2016 Lexus ES here.

2014 Infiniti Q50 Hybrid

2014 Infiniti Q50 High Resolution Exterior
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The Q50 is a very attractive car and the hybrid version of the car also gets admirable fuel economy. But this economy seems to come more from its lackluster power than from any kind of engineering brilliance. The steering is also numb and the handling is unlikely to impress any enthusiasts. It seems that so long as the G-Tron is as engaging to drive as other A4s, the car will win big with those who like both alternative and spirited driving.

Read our full review of the Infiniti Q50 here.


2016 Audi A4 G-Tron Exterior AutoShow
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A natural gas Audi is a weird idea, there is no way around that. But Audi’s push to make e-gas and then supply vehicles that can use it is a serious coup in the area of environmentally friendly vehicles. Conventional wisdom in the green car community says that cars need to use electricity in order to be environmentally friendly, either from a plug or from hydrogen. And while electric cars are generally better for the environment than gasoline, they aren’t truly carbon neutral. So if Audi can make e-gas carbon neutral on a large scale, it will be the clear winner. Also, the 2017 A4 looks really nice, not a bad choice no matter what is making it go.

  • Leave it
    • extra weight and less power is hardly ideal
    • no e-gas infrastructure, not much for natural gas
    • your electric car-owning friends won’t get it

Press Release

The Audi A4 Avant g-tron is the second model after the A3 Sportback g-tron that customers can run on compressed natural gas (CNG) or Audi e-gas. Its 2.0 TFSI engines has an output of 125 kW (170 hp) and torque of 270 Nm(199.1 lb-ft). The tanks for the Avant g-tron, which will become available in late 2016, are located under the rear of the car. They can hold 19 kilograms (41.9 lb) of gas at a pressure of 200 bar and are particularly light thanks to their novel layout.

2016 Audi A4 G-Tron Exterior AutoShow
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The inner layer consists of a matrix of gas-proof polyamide, while a second layer of mixed carbon-fiber-reinforced plastic (CFRP) and glass-fiber-reinforced plastic
(GFRP) ensures extremely high strength. The third layer made of glass fiber helps visualize any external influences. Epoxy resin is used to bind the fiber materials.
Gas consumption of less than four kilograms per 100 kilometers (8.8 lb per 62.1 miles) in a normal driving cycle means extremely low fuel costs for the customer.

With NEDC fuel consumption, the bivalent g-tron model drives over 500 kilometers (310.7 mi) on natural gas. When the gas left in the tank is less than about 0.6
of a kilogram (1.3 lb), gas pressure, falls below ten bar and the engine management automatically switches over to gasoline operation. This allows an additional range of 450 kilometers (279.6 mi). The A4 Avant g-tron is particularly ecofriendly when it runs on Audi e-gas.

2016 Audi A4 G-Tron Exterior AutoShow
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With this fuel, the company presents the first form of completely CO2-neutral long-distance mobility. Audi produces this fuel with the help of renewable energy, water
and CO2 in several power-to-gas plants. Using this method, the brand with the Four Rings makes surpluses of renewable energy storable. The e-gas can be bought with a
special filling-station card, which acts as a compensation instrument.

In parallel, Audi is continuing its research in the area of e-fuels. Together with its partners, the company has now developed a new method of producing e-gas. This secures the future supply for the rising number of g-tron models on the roads. Thanks to the new method, Audi e-gas is produced with the help of microorganisms by means of biological methanation. Compared with the previous used chemical process, the gas is produced at significantly lower ambient pressures and lower temperatures.

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