A car can be considered CO2 neutral if the amount of greenhouse gas used in creating the fuel is balanced against the CO2 emitted by the vehicle in operation.

Even as automakers move to increase the number of battery electric vehicles (BEVs), fuel cell vehicles and hybrids, internal combustion technology is not standing still. In fact, Audi believes that the future will see a mix of propulsion technologies and that internal combustion can play a role in producing vehicles that have minimal CO2 impact on the environment. As shown by Toyota's recent announcement to slow-walk EVs, the industry is looking into other alternatives besides pure electrics to meet ever-tightening Corporate Average Fuel Economy (CAFE) standards and zero-emission mandates like those enacted by California.

Rupert Stadler, Audi's chairman, asserts that "the future of mobility will be multi-faceted." And while Audi will offer pure electrics, like the R8 E-Tron, officials from the company insist that the combustion engine still remains an important element in the overall picture. Key elements in this strategy include more fuel efficient gas and diesel engines using such advanced technology as electric forced induction and stop-start technology that includes shutting the engine off when the vehicle is coasting. Audi will also offer a unique dual-fuel A3 that uses both compressed natural gas (CNG) and gasoline power that promises a range of around 750 miles in an A3.

Beyond the approach of upgrading the hardware, Audi is also looking at vehicle fuels themselves as a means to reduce carbon emissions. The company believes that an internal combustion car can be considered CO2 neutral if the amount of greenhouse gas used in creating the fuel is balanced against the CO2 emitted by the vehicle in operation. The argument goes that a BEV is only CO2-free if its electricity comes from nuclear, hydro, wind or solar sources and actually contributes to CO2 emissions if the electricity comes from a coal- or gas-fired generator. Following this line of reasoning to its logical conclusion, Audi is now involved in several projects to make ethanol, diesel and natural gas that uses CO2 in the production process.


Matt DeLorenzo is the former editor-in-chief of Road & Track and has covered the auto industry for 35 years, including stints at Automotive News and AutoWeek. He has authored books including VW's New Beetle, Chrysler's Modern Concept Cars, and Corvette Dynasty.




The most futuristic of these fuels is what Audi calls e-gas, a form of compressed natural gas produced through electrolysis and methanization. In partnership with SolarFuel, Audi has built a plant in northern Germany that uses wind power and electrolysis to create hydrogen from water. The hydrogen itself could be used in fuel cell cars. However, since the necessary infrastructure to deliver hydrogen to the automotive fleet is still being built, a second process has been added to methanize the hydrogen by using CO2 and water to create synthetic gas, a fuel that can be delivered through the existing natural gas lines and fueling stations. The CO2 used would come from organic waste that normally would enter the atmosphere through decomposition. This plant will produce 1,000 tons of methane per year starting in 2013 using 2,800 tons of CO2 in the process, which would, by Audi's calculation, give 1,500 Audi A3 Sportbacks enough fuel to run 15,000 km per year carbon neutral.

The second major fuel front is biofuels, principally ethanol and diesel, both of which can be distributed through the current fossil fuel infrastructure. Audi has teamed with Joule, a Bedford, Mass., based company to build a plant that uses bacteria to produce fuels that can be burned in conventional internal combustion engines. Called e-ethanol and e-diesel by Audi, this process combines waste water (which can be brackish or saline), bacteria, CO2 and photosyntheses to create a form of ethanol. The advantage here is that the ethanol produced is not food or plant based, but rather is created by the bacteria. A slightly more complicated and costly process can be used to create a diesel variant, which is purer than fossil-based diesel. Audi says that both fuels are economically viable in a market that currently commands $100 per barrel oil.

Audi A3 TCNG infographic

According to Heinz Hollerweger, Audi's Head of Development, Total Vehicle, in order for this approach to succeed, it will take new thinking on the part of vehicle producers and more importantly, those writing emission laws. "It means a new broad perspective, an open mind," Hollerweger maintains. "In the past, the focus was entirely on the emissions coming directly from the vehicle. Now we are analyzing the entire product lifecycle and orienting ourselves toward the principle of a closed-loop circuit where the negative environmental impacts are preferably avoided." It appears to be a sound approach, however, the questions remain, will it fly with the EPA and California regulators?


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    • 1 Second Ago
  • 41 Comments
      Egill Jóhannsson
      • 2 Years Ago
      Regarding Audi e-gas idea then similar, only better, idea is already in place in Iceland. You could call it liquid electricity as electricity is used to turn CO2 into liquid methanol. Electricity comes from a renewable source, geothermal power, and the CO2 comes from the same geothermal borehole. Therefore it is 100% CO2 neutral. The factory is already up and running and the fuel is being tested on flexifuel vehicle (E85) in Iceland running on 50% blend of gasoline and methanl (M50) with one M50 pump in Reykjavik. If the test is successful then bigger fleets will be tested and if successful millions of E85 vehicles will be able to use this fuel without any cost of change. The cost of changing pumps to M50 distribution will probably be minimum. More here: http://www.methanol.org/getattachment/Environment/Renewable-Methanol/Carbon-Recycling-International.pdf.aspx
        GoodCheer
        • 2 Years Ago
        @Egill Jóhannsson
        That's a wonderful setup, but unfortunately is really not scalable. It works in Iceland because clean renewable electricity is almost free. For the rest of us suckers, the costs would be very high.
      AngeloD
      • 2 Years Ago
      Kudos to Audi for their research into alternate fuels. However, claiming a motive based in the religious mythology of anthropogenic "global warming" is a farce. When will the European governments and big corporations stop trying to rip-off the taxpayers and consumers with this faith-based religious belief system?
        AngeloD
        • 2 Years Ago
        @AngeloD
        ""When will the European governments and big corporations stop trying to rip-off the taxpayers and consumers with this faith-based religious belief system?"" I sould add the California State government to that list of green-energy rip-off scams and enviro-religious fundies.
        ksrcm
        • 2 Years Ago
        @AngeloD
        Why are you downvoting him? There is very little to NO doubt that: - Earth climate is changing - Weather patterns are changing - Average temperatures are higher But, to say that humans are responsible for it is akin to a shaman saying that it rained after his dance because he persuaded the Gods to send rain.
      Kris
      • 2 Years Ago
      Now this is the future if you ask me, not the electrics. And the best part about it, we get keep the sweet engine noise.
        k_m94
        • 2 Years Ago
        @Kris
        YES, as a fan of big noisy engines, it would be nice to have internal combustion be a sustainable option in the future without worrying about ever increasing oil prices (and dwindling, harder to reach supplies in the middle east) and all the associated issues. Not to mention, the fact that you could theoretically be driving a 400hp V8 and still be just as carbon neutral as your neighbor's electronic appliance.
      paulwesterberg
      • 2 Years Ago
      Synthetic natural gas sounds expensive - I doubt that industry will invest in the technology when they have access to cheap gas produced by fracking. Audi likes to appear to be investigating alternative fuels(hydrogen) while doing very little to actually provide solutions that are efficient and reduce fossil fuel use. The additional energy conversion steps required make this type of biofuel less efficient than pure electric vehicles.
        k_m94
        • 2 Years Ago
        @paulwesterberg
        I'm a bit skeptic about the whole synthetic natural gas, but the bacterial ethanol/diesel (or from algae, the process is similar) is something I always envision as capable of replacing fossil fuels with the right motivation.
          paulwesterberg
          • 2 Years Ago
          @k_m94
          Biofuels could be a useful source of energy, but their expense will make them impractical from a cost/efficiency standpoint if the fuel is burned with most of the energy ending up as waste heat. Methanol fuel cells or some other efficient chemical/electrical process would be needed to make the system viable.
      • 2 Years Ago
      [blocked]
        Ryan
        • 2 Years Ago
        Nuclear isn't carbon neutral since the mining and enrichment process takes a lot of energy. Energy that probably comes from dirty sources.
          AngeloD
          • 2 Years Ago
          @Ryan
          No, we have perfectly safe breeder-reactor technology that substantially removes the nuclear power cycle from the carbon cycle. However, it violates the tenets of the new age enviro-religions and therefore must be quashed. And the lefties accuse the conservative Christians of trying to impose THIER religion on everyone, LOL.
          • 2 Years Ago
          @Ryan
          [blocked]
        shigllgetcha
        • 2 Years Ago
        Nuclear waste has nothing to do with carbon neutrality.
          • 2 Years Ago
          @shigllgetcha
          [blocked]
          GoodCheer
          • 2 Years Ago
          @shigllgetcha
          Well, it can certainly be dirty even while being carbon-neutral. We'll have stopped using fossil fuels long before we no longer need to manage and protect ourselves from the spent fuel. "Carbon" has just come to be the term for "external cost".
        k_m94
        • 2 Years Ago
        Nuclear radiation and radioactive waste taking millions of years to decompose is nasty stuff. But technically, it is carbon neutral in that the plant doesn't produce or use carbon based products. Nuclear is cleaner than most people think, but unless we plan on re-reacting the spent fuel rods and heavy water to the point they are inherently stable and inert, it isn't really a true "green" solution, in fact, it can be pretty dangerous in the event of failiure or improper operation.
          • 2 Years Ago
          @k_m94
          [blocked]
        Sj027
        • 2 Years Ago
        Half life of many radioactive waste types is over 5 million years. Depleted Uranium will virtually never stop contaminating the Middle East, in Baghdad something like 1 in 3 babies are born with a severe birth defect due to Depleted Uranium being used as a weapon of war. I really don't think nuclear is the 'cleaner' and 'safer' energy alternative that it's hyped up to be.
          • 2 Years Ago
          @Sj027
          [blocked]
        Jeff R
        • 2 Years Ago
        There is a difference between carbon emissions and radioactive waste. If a technology does not increase atmospheric CO2 levels, it is said to be "carbon neutral". A nuclear power plant uses nuclear fission to heat water, it doesn't burn anything that emits CO2, so it is said to be "carbon neutral".
          • 2 Years Ago
          @Jeff R
          [blocked]
        SloopJohnB
        • 2 Years Ago
        Nuclear isn't carbon neutral considering the CO2 released during uranium mining and enrichment. The actual fission process doesn't release CO2.
      protovici
      • 2 Years Ago
      EPA and California regulations = major technology set backs in energy. Awesome state, but open the door to new ideas and maybe your finances will straighten out. Just a thought.
        icemilkcoffee
        • 2 Years Ago
        @protovici
        The article said that Audi is doing this research in order to meet the CA standards. So it sounds like CA\'s carbon emission standards is spurring new innovations.
          paulwesterberg
          • 2 Years Ago
          @icemilkcoffee
          California currently gets 35% of its electricity from renewable sources, if they could transition their transportation system to locally produced clean energy the states economic problems would be solved.
        Ryan
        • 2 Years Ago
        @protovici
        They don't want to open the door because the people who live there now like one another because they share a similar set of beliefs.
          protovici
          • 2 Years Ago
          @Ryan
          Have you ever been to Cali???
          MONTEGOD7SS
          • 2 Years Ago
          @Ryan
          Only about half. A good portion of the state is as conservative as they come, but they are drowned out by the liberals in the two big cities. NorCal, the whole central valley, parts of SoCal are all very conservative.
      joeboarder108
      • 2 Years Ago
      Does autoblog actually employ copyeditors? "...an A3 that uses... in an A3." - Redundant much? "Audi is now involved in several projects... that uses CO2..." - Subject verb agreement "...organic waste that normally would enter the atmosphere..." - Spraying poop into the air? "called e-ethanol and e-diesel..., this process..." - Dangling modifier "... photosyntheses..." - Not a word This man seriously used to be an editor-in-chief? He writes like a college freshman. Even his "correct" sentences are unwieldy at best.
      shigllgetcha
      • 2 Years Ago
      "technology that includes shutting the engine off when the vehicle is coasting." Do modern cars not do this already? I didnt think any fuel was drawn through the cylinders while you coasted in gear
        SloopJohnB
        • 2 Years Ago
        @shigllgetcha
        Only at closed throttle and certain rpm ranges. The ignition system still runs, only the injectors go to zero pulsewidth.
      RC
      • 2 Years Ago
      This is all about parts and service. How the hell are they going to make $$$ out of an EV which has a minimal amount of moving parts? They must keep the engine alive.
      Marcopolo
      • 2 Years Ago
      It's good to see lot's of R&D into different methods of providing superior, less pollutant automotive fuel. All these efforts should be applauded, but most lack any realistic, economic ability to become viable without massive government subsidies. Meanwhile, while all this R&D goes into the relatively tiny amount of atmospheric pollution created by the spider-monkeys of the automotive industry, an army of 1000 lb Gorrila's continue to pollute on a colossal scale ! The world total automotive fleet, doesn't equal 2% of the toxic pollution spewed into the bio-sphere by shipping every year ! In many ways, the pollution by the use of No.6 Marine Fuel (bunker oil) is far more damaging to human health, with hundreds of thousands of attributed deaths each year. The irony is that while everyone talks about passionately about the pollution created by cars and trucks, this far more serious source of pollution, remains relatively unknown ! Even more ironic is that the means to eliminate this toxic practice, already exists .
        skierpage
        • 2 Years Ago
        @Marcopolo
        Stop being obtuse. CO2 emission is *different* from toxic airborne pollution. Global warming is the far more serious problem. Both need fixing. There is no irony.
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