If you're confused when someone says "Audi e-tron," and you're not sure which electric car it means, don't feel bad--we're confused too.

Audi may have more branded electric car concepts, prototypes, test vehicles, limited-production cars, and planned volume-production plug-in electric models than any other maker in the world.

The company has chopped and changed its plug-in lineup several times over the past few years, making it difficult to keep track. Some models have been postponed, others dropped, and others introduced.

Below is our full guide to all the e-tron models--plus the natural gas A3 g-tron--so you can keep track of Audi's increasing low-emission range.


Production e-tron models


2014 Audi A3 e-tron plug-in hybrid presentation, Berlin

2014 Audi A3 e-tron plug-in hybrid presentation, Berlin

Audi A3 Sportback e-tron

Unlike the all-electric A3 originally unveiled under the e-tron banner, the production Audi A3 e-tron will be a plug-in hybrid, part of a range of plug-ins planned for the new Audi A3, sharing its chassis with the upcoming Volkswagen Golf.

The 2015 Audi A3 e-tron made its official debut at the 2013 Geneva Motor Show, and then appeared again at the New York Auto Show.

It uses a turbocharged 1.4-liter engine, paired to a six-speed dual-clutch gearbox, with a 75 kilowatt electric motor sandwiched between the engine and transmission. Together, there's a full 204 horsepower and 258 pounds-feet of torque available--62 mph comes up in just 7.6 seconds, says Audi. Click on the links below for further details.


Audi A3 g-tron first drive, Berlin

Audi A3 g-tron first drive, Berlin

Audi A3 g-tron

The A3 g-tron is the odd one out in this list, for it is neither hybrid nor electric.

Instead, it's an A3 running on natural gas--a much cleaner fuel than typical oil-based fossil fuels. Audi wants to make it even cleaner than that, by setting up a process that allows g-tron drivers to fill up on "e-gas", a clean natural gas derived from the methanation of hydrogen, powered by electricity from wind farms.

It sounds complicated, but reduces the net emissions of the vehicle to negligible amounts. Find out about the car and Audi's green natural gas plans below.


2012 Audi A6 L e-tron concept

2012 Audi A6 L e-tron concept

Audi A6 e-tron

The concept A6 e-tron, unveiled at the 2012 Beijing Auto Show, paired a long-wheelbase version of Audi's A6 sedan with a 2.0-liter direct-injected gasoline engine and an electric motor rated at 70 kW (94 hp) peak output, for a total powertrain output of 306 hp.

Now, Audi has confirmed a production version of the model--though the plug-in hybrid luxury sedan will only be sold in China. It's being built with FAW, Audi's Chinese joint-venture partner. We're still awaiting details of the A6 e-tron's production powertrain.


Audi R8 e-tron track drive, Berlin Tempelhof Airport

Audi R8 e-tron track drive, Berlin Tempelhof Airport

Audi R8 e-tron

We're tentatively placing the R8 e-tron supercar in the "production" column right not, because at last count, Audi said it planned to build a limited run.

That may be subject to change, though, as the R8 e-tron has been slated for production then cancelled more times than we can count.

An electric R8 was first unveiled at the Frankfurt Motor Show all the way back in September 2009, and since then Audi has gradually developed it into the car we see today. Click on any of the links below to follow the car's progress so far.

Volkswagen e-Up test drive, Berlin, March 2014

Volkswagen e-Up test drive, Berlin, March 2014

Audi e-tron concepts and future models


Audi e-tron city car

Previously, the A1 e-tron was Audi's smallest e-tron model--but another looks to be on the way.

Inside EVs reports Audi is considering a model based on the recently-launched Volkswagen e-Up--an electric version of the minicar sold in Europe.

It could actually be more powerful and offer more range too--while the regular e-Up gets 93 miles of range, Audi is said to be aiming for 124 miles with its own variant. With 116 horsepower, it will even offer sub-10 second 0-62 mph times.

Unfortunately it's unlikely such a thing will reach the U.S, since the Up hasn't been "federalized" to meet U.S. safety standards.


Audi A1 e-tron Dual-Mode Hybrid

Audi A1 e-tron Dual-Mode Hybrid

Audi A1 e-tron

The A1 e-tron Concept, first shown as a concept at the 2010 Geneva Motor Show, is in many ways our favorite of all the e-trons, mostly for its ultra-cool range extender.

The battery electric subcompact uses a fist-sized Wankel rotary engine under the rear deck to generate electricity that powers the electric motor driving the front wheels, once the battery pack has been depleted.

A test fleet of 20 Audi A1 e-trons has been operating in Munich and elsewhere, gathering data on travel times, battery use, charging behavior, and how often the range extenders comes into use.

At last count, there were no plans to put the A1 e-tron into production. That's a shame--we drove the prototype in 2013, and it had a lot of potential.


2011 Audi A2 Concept

2011 Audi A2 Concept

Audi A2

The Audi A2 Concept was unveiled in 2011 at the Frankfurt Motor Show, and it's the only dedicated body and chassis among all the e-trons. The rest are derived--though in some cases with quite major adaptations--from production gasoline cars.

The A2, intended to be a direct competitor for the all-electric BMW i3 (which offers an optional range extender as well), is not as adventurous a design as the i3, which has a carbon-fiber reinforced plastic body atop an aluminum platform with the battery pack in the floorpan.

Like the A1 e-tron though, the all-electric A2 may be put on ice. In fact, we've heard very little about the Audi A2 at all since Frankfurt 2011--if the company is working on something, it isn't giving much away.

2013 Audi A4

2013 Audi A4

Audi A4 e-tron

Audi hinted a few years back that it will offer a plug-in hybrid variant of its next-generation A4 sedan, in 2015 or thereabouts.

The Audi A4 is the brand's highest-volume vehicle in the U.S., and the next A4--to be launched by 2015--is likely to offer a breathtaking variety of powerplants: gasoline, diesel, hybrid, and plug-in hybrid.

It could use the same 1.4-liter gasoline plug-in powertrain as the A3 Sportback e-tron. There are rumors of a regular hybrid variant too--though Audi and parent Volkswagen are likely to make best use of the plug-in hybrid technology over the next few years.


2013 Audi Q7 TDI S Line

2013 Audi Q7 TDI S Line

Audi Q7 e-tron Plug-In Hybrid

An all-new version of the Audi Q7 large sport-utility vehicle will be introduced within a couple of years.

It will share a plug-in hybrid powertrain, based on the 3.0-liter supercharged V-6 now used in the Porsche Cayenne S Hybrid and the Volkswagen Touareg Hybrid.

But the plug-in hybrid variation will have a much larger lithium-ion battery pack.

The Q7 e-tron Plug-In Hybrid will share its basic body structure and electrification components with the upcoming Bentley sport-utility vehicle, previewed as the EXP 9 F Concept at the Geneva Motor Show a few years back.

The production version of the Bentley SUV (we shudder just writing those words) has been confirmed to offer a plug-in hybrid model using the 3.0-liter V-6 hybrid system.


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