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Transportation Science

Audi Creates "Fuel of the Future" Using Just Carbon Dioxide and Water 486

EwanPalmer writes: German car manufacturer Audi says it has created the "fuel of the future" made solely from water, carbon dioxide and renewable sources. The synthetic "e-diesel" was made following a commissioning phase of just four months at a plant in Dresden, Germany. Germany's federal minister of education and research, Dr Johanna Wanka, said she has already used the fuel in her Audi A8, and the company hopes to produce at least 160 liters of the crystal clear fuel every day in the coming months. "This synthetic diesel, made using CO2, is a huge success for our sustainability research," Wanka said. "If we can make widespread use of CO2 as a raw material, we will make a crucial contribution to climate protection and the efficient use of resources, and put the fundamentals of the 'green economy' in place."
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Audi Creates "Fuel of the Future" Using Just Carbon Dioxide and Water

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  • by Viol8 ( 599362 ) on Monday April 27, 2015 @10:20AM (#49559909) Homepage

    ...renewables are going to have their work cut out for themselves just supplying a majority percentage of the power for national electricty grids. I'm not sure where they think the extra renewable power to do this will come from.

    Now if they plugged the process into a nuclear power plant OTOH...

    Of course the big question is how efficient is the process? Is it more efficient than just using the electricity to charge up batteries in an electric car for example?

    • by goodmanj ( 234846 ) on Monday April 27, 2015 @10:26AM (#49559987)

      You're right that we don't have enough renewable energy yet to make this a useful technology. But hopefully that day is coming.

      Re synthetic diesel, it's like I've always said: screw the "hydrogen economy", hydrogen is cryogenic, low-density, and difficult to work with. You'd be better off joining those hydrogens to some nice stable carbon atoms to create a storable, pumpable, relatively safe room-temperature liquid fuel.

      Is it more efficient than just using the electricity to charge up batteries in an electric car for example?

      Maybe, maybe not, but I guarantee you it has a higher energy density than batteries, which is super important for vehicle applications.

      • by monkeyzoo ( 3985097 ) on Monday April 27, 2015 @11:03AM (#49560457)

        What is the chemical composition of the output I wonder? Looks like the steps are:

        1) 2x H2O --> 2 H2 + 1x O2
        2) 2x H2 + 1x CO2 --> 1x H2O & ?? (C, O, & H2 are left over)

      • by LWATCDR ( 28044 ) on Monday April 27, 2015 @11:56AM (#49560927) Homepage Journal

        "Is it more efficient than just using the electricity to charge up batteries in an electric car for example"
        Think of ships, planes, and remote locations where you must transport fuel like Alaska.

        "You're right that we don't have enough renewable energy yet to make this a useful technology. But hopefully that day is coming."
        No it will not.
        Nuclear is the key to low carbon power. Wind and Solar will help but they do not work well as baseload. Thorium based nuclear and possibly Fusion aka Lockheeds High Beta reactor is what is needed.

        • Definitely thorium, and it would be even more eficient as you can use the high heat to split water efficiently, but other high temp reactors would work great as well.

          Recent navy research has shown it may be easier to concentrate oceanic C02 than atmospheric, meaning we could eventually retrofit old oil platforms with a nuclear core and fill up tankers with synthetic fuels.
      • by mlts ( 1038732 )

        I feel the same way. Hydrogen takes a lot of effort to store compared to a compound like diesel or even gasoline which can be stored in a (mostly) unpressurized tank.

        TFA has me wondering a number of points:

        1: What is the energy density of this fuel compared to diesel or gasoline. Is it as dense as diesel, or is it about half to 3/4 as much, like ethanol?

        2: How easy is it to have a fuel cell use it, as opposed to direct combustion?

        3: How toxic is it? Ethanol is arguably the least toxic, but one atom aw

      • by Rei ( 128717 ) on Monday April 27, 2015 @12:13PM (#49561073) Homepage

        "Maybe, maybe not"? Please, you know that the answer is "not even remotely close". Even when you start with petroleum as your feedstock and only waste 10-15% of the energy it contains in refining and distribution, you've still got the car only turning 20% of the energy therein into useful kinetic energy (25% in the case of diesels), versus an average of about 85% of the electricty into kinetic energy (minus about 8% transmission losses), plus automatically gaining hybrid-style regen. Even if the process was 100% efficient - which it won't be anywhere even close to that - just the difference in propulsion technolgies would put the EV at 4 times the efficiency. Based on related processes, I'd wager that this tech is probably along the order of 30% efficient, so you're looking at about 13 times more range per kWh on an EV than a ICE car fuelled by this fuel. Which means 1/13th as many square kilometers of wind turbines, 1/13th as many solar panel factories, 1/13th as many dammed rivers, etc. Yes, it really matters.

        But come on, don't play dumb and pretend that you actually think that the efficiency of taking electricity, extracting gases from the air, converting them into a mixture of complex hydrocarbons, then burning them in an ICE and facing Carnot losses, is somehow "maybe, maybe not" more efficient than using the electricity directly.

        it has a higher energy density than batteries, which is super important for vehicle applications.

        It really, really isn't. Almost everyone on the planet would be driving an EV at today's energy densities if one factor was significantly improved, but that factor isn't energy density. It's cost per kilowatt hour.

        A 250Wh/mi EV that can go 400 miles (8 hours driving without a stop at an average speed of 60mph) needs 100kWh. At a reasonably good but not spectacular 200Wh/kg, that's 500kg. Due to electric drivetrains' superior power density, switching a low power gasoline drivetrain to an equivalent electric one saves about 100kg. Switching a high power gasoline drivetrain to electric can save a couple hundred kilograms. So you're increasing the weight of a car by a few hundred kilograms. You really think your average consumer would give a rat's arse if their car is a couple hundred kilometers heavier if it lets them drive on fuel that costs a third as much?

        Of course, these are only a couple of the issues (I'll ignore environmental ones for now because I know a lot of people here don't give a rat's arse about them). Added weight hurts handling on cornering. But EVs make better power to weight ratios easier, and especially improve performance on low end torque. They also give designers a lot more flexibility on placement of components, which can translates into things like more spacious interiors for a given vehicle footprint, and almost always means a lower CG. One has to charge, but one never has to go to a gas station, and most people would find plugging in in their garage much more convenient than a special trip to a gas station and standing outside in whatever weather. This leaves open the question of charge times, of course. But if you can drive hundreds of miles on a single charge and charge up on a fast charger during lunch and then take off again, it's pretty irrelevant. Gasoline cars need big tanks to minimize the inconvenience of having to stop for gasoline regularly in your daily life. Using fast chargers of course means having a fast charger infrastructure, but that's an eminently addressable chicken and egg problem. Modern li-ion batteries deal quite well with fast charges.

        The short of it is, if today's batteries were cheap enough - no better density or anything else - electric cars would very quickly take over the market place. Other improvements in technology will improve the sales proposition, but they're not essential.

        • by Solandri ( 704621 ) on Monday April 27, 2015 @02:32PM (#49562593)

          Even when you start with petroleum as your feedstock and only waste 10-15% of the energy it contains in refining and distribution, you've still got the car only turning 20% of the energy therein into useful kinetic energy (25% in the case of diesels), versus an average of about 85% of the electricty into kinetic energy (minus about 8% transmission losses), plus automatically gaining hybrid-style regen. Even if the process was 100% efficient - which it won't be anywhere even close to that - just the difference in propulsion technolgies would put the EV at 4 times the efficiency.

          Slow down there. You're comparing the complete-cycle efficiency for petroleum to just the end-stage efficiency for electric. That electricity needs to be made somehow. Toss in 40% efficiency for coal plants (we'll leave out pumping/mining and fuel transport costs for now, assuming they're similar for oil and coal), battery charging efficiency of about 75% [futurepundit.com] (discharge efficiency is unspecified, but since the EPA mileage estimates are based on battery capacity it's safe to ignore it), and the 85% motor efficiency you've specified, and suddenly your EV is .4*.75*.85 = 25.5% efficient. Same as a diesel.

          This is the big thing a lot of EV proponents miss. Their EV is cheaper to operate not because the EV is more energy-efficient, but because coal is so much cheaper than gasoline. Coal costs about $50 per ton. A ton of coal has approximately 24 GJ of energy. That's about 0.21 cents/MJ. Gasoline costs about $3/gallon, and has about 120 MJ/gallon, or 2.5 cents/MJ. For the same amount of energy, coal is an order of magnitude cheaper than gasoline, which gives the EV a huge advantage in terms of operating costs. This is not a bad thing - being able to transfer a cheaper but traditionally static energy source into use in a mobile application is an economic win. But don't confuse it for better efficiency.

          Yes you could argue that we can make electricity from renewables. But the vast majority of the cost of renewables is in the initial production of the turbine or PV panels. Operating costs are nearly nil (limited to maintenance). So for a fair comparison you then need to incorporate production and transport costs. At which point renewables lose because on a per Joule delivered basis, even with coal plants being only 40% efficient, coal is still cheaper than wind and solar power. (Wind is only about twice the costs of coal, so cheaper than gasoline, but I suspect solar would be about the same cost as gasoline.)

    • Re: (Score:2, Insightful)

      by Eunuchswear ( 210685 )

      .renewables are going to have their work cut out for themselves just supplying a majority percentage of the power for national electricty grids. I'm not sure where they think the extra renewable power to do this will come from.

      No, the biggest problem with wind in particular is that to get reasonable amounts of energy you have to install large overcapacity.

      Which leads to the problem of what you do with that energy on a windy day.

      Up till now Germany has been selling it to (among others) France, for almost nothing. This is bad for Germany (they get very little money) and bad for France (it makes the nuclear fleet less profitable).

      Making synthetic fuel when you have energy to spare could be a pretty smart storage mechanism.

      Wonder w

      • Up till now Germany has been selling it to (among others) France, for almost nothing.

        For example they're currently exporting about 2.5GW to France.

        http://gridwatch.templar.co.uk/france/ [templar.co.uk]

      • by afidel ( 530433 )

        Wonder what the efficiency is like though.

        I'd assume it will end up somewhat close to Fischer–Tropsch, about 50-60% max efficiency.

        • by itzly ( 3699663 )

          I'd assume it will end up somewhat close to Fischer–Tropsch, about 50-60% max efficiency.

          With added losses due to having to extract CO2 from the air, hydrogen from water, and the conversion from CO2 to CO.

    • by radl33t ( 900691 )
      10% Atacama desert in Chile could produce enough fossil fuels from solar input to displace petrol and diesel.
    • by nonsequitor ( 893813 ) on Monday April 27, 2015 @11:12AM (#49560535)

      Regardless of the efficiency of the process, overgeneration of renewable power is still a huge problem. Germany actually pays its neighbors to take it when the wind is blowing and the sun is shining as the price of electricity between utility companies goes negative.

      There are a few things we currently do with excess power, the ideal option is to store it until we need it, such as with compressed air in salt caverns.

      In many cases, they dump it as heat into rivers as the storage infrastructure simply doesn't exist. This new option seems to be a great way to sequester carbon and deal with excess power generated through renewables. It also reduces our dependency on oil without having to sell new vehicles to utilize it, which is a very good thing.

    • is the inability of storing the energy when demand is low, but supply is high. using this energy to make fuel would be a good use.
  • It's called a plant. It takes water, C02 and light, makes hydrocarbons - whose root words are water + carbon.

    The real question is how much ENERGY does it take to take water, CO2 and make a hydrocarbon.

    • by radl33t ( 900691 )
      Its more efficient than a plant derived fossil fuel, if that's the comparison your itching to make.
  • by NEDHead ( 1651195 ) on Monday April 27, 2015 @10:27AM (#49559993)

    If they could capture the water from the tailpipe, gather the CO2 from the air, and use a windmill on the roof of the car to generate the power to make the fuel, they could DRIVE FOREVER!!!

    • In a sufficiently strong crosswind, yes.

      (Why do you think we have a grid road system, if not for tacking?)

    • In b4 kickstartign campaign asking for 10 thousand to implement just this idea.
  • There isn't enough CO2 in the atmosphere to make this work. We would risk starvation by reducing CO2 levels below the level plants need. People forget that CO2 is plant food.
    • by Amigan ( 25469 ) on Monday April 27, 2015 @10:36AM (#49560095) Homepage
      Ethanol was going to save us. Then farmers / growers sold all their corn to ethanol producers, and the food chain suffered as feed for animals got more expensive, exports to 3rd world fell, and food riots started...
    • by Ihlosi ( 895663 )
      There isn't enough CO2 in the atmosphere to make this work.

      There was plenty of CO2 for plants to go around even before humans started burning coal at industrial scales.

      This is basically just un-burning coal. And oil. And natural gas.

      • And then burning it again. We're not just making barrels of diesel to look at like art - it's going back into a cylinder to be compressed with air until it explodes and blows out the tailpipe again.

    • by Jeremi ( 14640 ) on Monday April 27, 2015 @10:50AM (#49560283) Homepage

      There isn't enough CO2 in the atmosphere to make this work.

      That's okay, because they are unlikely to be taking the CO2 out of the atmosphere anyway. It would be much cheaper and easier to capture and reuse the outputs of an existing CO2 source (e.g. a coal plant) than it would be to suck CO2 out of the ambient air.

    • And you're forgetting that once someone uses the diesel, it's CO2 in the atmosphere again.

      What, did you figure that Audi was just making diesel to pump back into the ground and forget about?

  • But does this stuff require clean, fresh, potable water? Lots of people are bent out of shape about fresh water shortages.

  • by aaarrrgggh ( 9205 ) on Monday April 27, 2015 @10:33AM (#49560065)

    All well and good, but doesn't exactly solve the problem of greenhouse gas emissions.

    The most interesting application of things like this is if they can take advantage of spikes of excess energy availability-- essentially making them a battery.

    • All well and good, but doesn't exactly solve the problem of greenhouse gas emissions.

      Sure it does; you'd be extracting this carbon out of the air, or from a process stream that would otherwise dump to the atmosphere. Best case you have a net zero carbon emission, worst case you're using the same carbon twice (industrial waste stream to vehicle fuel to emissions) which is still a significant reduction.

      Plus it cuts down on other pollutants, eliminates the environmental damage from oil extraction itself, eliminates emissions from the refining process and possibly reduces transport energy costs

    • All well and good, but doesn't exactly solve the problem of greenhouse gas emissions.

      That depends entirely on the source of CO2

    • All well and good, but doesn't exactly solve the problem of greenhouse gas emissions.

      Yes it does. The problem with CO2 as a greenhouse gas is that we're taking carbon that was part of the long-term carbon cycle (i.e., fossil fuels) and making it part of the short-term carbon cycle. In contrast, this process takes carbon that was already part of the short-term carbon cycle and keeping it as part of the short-term carbon cycle. It's "carbon-neutral."

      Using synthetic fuels like this (as well as biofuels) won't

    • It doesn't completely solve the problem, but it allows for some recycling where there is no solution today.

      Pull burned carbon from air > make diesel > burn diesel > go to step 1.

      How is this not preferable to:
      Drill miles into the ground > inject god-knows-what fracking liquids > extract oil > flare off natural gas found with oil > ship oil to refinery > refine oil > burn diesel > go to step 1.

      I don't understand the mentality of "It doesn't solve every aspect of every problem nea

    • All well and good, but doesn't exactly solve the problem of greenhouse gas emissions.

      Sure it does. (Not that one small pilot project solves the problem, I mean if the tech is scaled up.) It's carbon-neutral just like biofuels are, it does not add any net CO2 to the atmosphere: it only puts in what it took out to make the fuel in the first place. (I suppose your could even use it to remove CO2, to get us back to 350ppm via carbon sequestration -- make up a bunch of "blue crude" and then stick it underground

  • And Al Gore's great-great-great grandson will be selling holodiscs that talk about the impending ice age due to our excessive use of CO2.
    • by itzly ( 3699663 )

      This process is CO2 neutral. As the fuel is burned, the carbon is released back into the atmosphere.

  • TFA's infographic shows the plant being powered by "ecological power generation," but this thing requires, say, a 40 acre wind farm to produce 200 liters a day then there wouldn't be much benefit. The figure to beat is whether it costs less energy to generate this synthetic diesel as it would cost to charge a battery-powered (e.g. Tesla) car.
    • by itzly ( 3699663 )

      Very unlikely that this is a practical solution in the given form. Just the electrolysis step alone wastes more energy than the entire windmill to Tesla pathway.

    • It is pretty much guaranteed that charging an electric car takes less energy than this. Internal combustion engines are only ~35% efficient, so even if the process of creating the fuel is 100% efficient (which it is not, it is probably in the ideal case about 50% efficient), you would still need 3x the energy to create the fuel.
  • Hopefully, the exports will be off the charts. California needs the economic growth.

  • So, the have re-discovered syngas: brilliant!
    http://en.wikipedia.org/wiki/S... [wikipedia.org]

    Apart from the amusing name of the minister, no much to see here

  • Is the production process automated, or is it a hand job? [urbandictionary.com].

  • From the article:

    The clear fuel is made form juts water, air and renewable energy

    I wonder what "form juts water" is and how much does it cost. It's probably quite uncommon.

  • I assumed based on the /. headline that this article was just a delayed April 1 joke. Breaking the two double bonds in a CO2 molecule (depending how you count) and one or two HO bonds in water to produce a single carbon atom oxygenated hydrocarbon like formaldehyde [H(CO)H] or methanol [H3COH], both of which have low energy densities, is going to take a lot of external energy. Doesn't seem practical to me. Maybe I'll read the article.
    • by itzly ( 3699663 )

      Since burning the fuel returns it back into CO2 and H2O, the amount of energy in the various bonds is irrelevant. All the energy you put in will come out again.

    • by radl33t ( 900691 )
      It seems entirely practical given that plants have done it for billions of years at lower inefficiencies. There are many high temperature based solar to fuel schemes using various redox cycles being researched by labs all over the world. Breaking the cycle up makes it easier to run at high temperatures and 20-40% solar to fuel net efficiency. Given that the major expense in these schemes are the fields of heliostats necessary to concentrate the solar radiation, the cost is likely to be similar to ivanpah. N
  • Soda (Score:5, Funny)

    by unixcorn ( 120825 ) on Monday April 27, 2015 @10:59AM (#49560405)

    Shoot, now there will be a CO2 shortage and my soda will be flat.

  • And how much energy does it take to create this fuel? How much does it cost?

    Would a tank full of it allow the car to travel a comparable distance and speed as a similar-sized tank full of gasoline or diesel fuel?

    Unless it is or can be economically comparable to CURRENT costs, its useless.

  • I recall reading the USN had also created fuel using seawater by extracting H2 and CO2 from seawater and turning it into fuel via a catalyst, is this the same thing?

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