Science-y Goodness: How Sun and Water Just Turned Carbon Dioxide Into Jet Fuel


Who’s ready for a little science? It’s pretty awesome science, if that helps get you excited. Apparently, scientists in Europe have successfully turned carbon dioxide into jet fuel using water and solar energy. What sort of wizardry is this? Here’s how it works.

Solar Fuel Creation

Basically, what happens is you get a bunch of carbon dioxide from the atmosphere along with a lot of water. Throw them into a contraption that harnesses the sun to provide heat, and then crank it up to over 2000 degrees Celsius. The molecules start to break up, and you’re left with oxygen, hydrogen, and carbon monoxide. Next, you have to get rid of the oxygen (release it into the air) or the whole thing might blow up in the last step. Finally, the hydrogen/carbon monoxide mixture (which is called syngas) can be turned into fuel using the Fischer-Tropsch process. The end result is the same fuel you have today. Science!

This sounds too good to be true. After all, water, carbon dioxide, and the sun are three ingredients which are not going to run out. Well, you know, the sun will run out in billions of years, but whatever. And while water is a scarce resource here in California, that’s probably why you don’t build the plant here. There will always be a supply of water somewhere, and if salt water can be made to work (certainly at a higher cost), then even better. As for carbon dioxide, well, we want to pull that out of the air anyway. So this is excellent in that regard.

With all that being said, it really is too good to be true… for now. The biggest issue is the sheer cost of doing this and the low yield of the process. It is horribly inefficient right now with a process efficiency of only 1.73 percent. That means you need a ton of water and carbon dioxide along with a silly amount of energy to make a little bit of fuel. Scientists think that this process could become economically viable if they can get efficiency into the neighborhood of 15 percent. That’s a long way to go. Even then, it would take a facility of 1 km2 to produce just over 5,000 gallons of fuel. That’s not a lot. So we’d need some serious efficiency gains here to make this really work.

There are also environmental issues to consider. It is a carbon neutral process because you’re pulling carbon dioxide out of the air for this. That means when you burn the fuel, it just goes right back. That’s very different than when you pull something out of the ground and then add carbon dioxide to the air when you burn it, because that is carbon dioxide that wasn’t there before. That being said, there have to be some environmental impacts to this process. They used something called ceria (cerium oxide) to extract the oxygen. I have no idea if that has an environmental impact. And of course, just building the massive facility required for something like this would have an impact. But overall, it would be a tremendous breakthrough if the efficiency can be improved.

It seems to me that the thing that’s really innovative here is the idea that you can use solar energy to power this process. The rest of the concepts aren’t really new, but using a solar reactor means you dramatically improve the long term value here. That’s why it seems to be very green, especially in comparison to the options we use today.

If the challenges can be overcome, this will allow the creation of fuel from a virtually unlimited supply of basic materials. That’s pretty cool. But as with most sustainable alternative fuels, we’re a long way away from being able to actually put it into serious, widespread use.

(Tip of the Hat to Airline Weekly)

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15 comments on “Science-y Goodness: How Sun and Water Just Turned Carbon Dioxide Into Jet Fuel

  1. How different is this from the US Navy announcement that they are working on converting seawater to jet fuel?

    1. I’m sure there are differences in the details but it’s basically the same thing. The Navy setup revolves around using the nuclear reactor on an aircraft carrier instead of the sun probably being the primary difference.

      I’m much more interested in how this applies when coupled with the ITER project going on right now. The goal of ITER is to scale up lab experiments and work out the engineering issues for a full scale commercial fusion reactor.

      Fusion power being much more compact than thermal solar, the efficiency required for viability goes down significantly.

      1. I don’t think you can couple this at all with the ITER project. ITER uses Deuterium and Tritium for the nuclear reaction, at temperatures way higher than the needed 2000 degrees C in this project.

        I’ve been fortunate to visit the Joint European Torus (JET) in the UK a couple of years ago, which is the predecessor of ITER. The main issue at the moment is to stabilize the plasma in the Tokamak and therefore preventing it to hit the wall – which will melt directly.

        The fusion-project is of a completely different league and light years away from even thinking of putting it in an airplane. This project, even though still not viable, shows much more near-future possibilities to create jet fuel. I don’t think you’d want a million degrees fusion reactor in any airplane at the moment ;).

        Or do you mean using the energy from ITER (or DEMO, which follows next) to heat things up? I can’t look into the economics of it, but I guess it’s much more expensive than using freely available sunlight.

        1. Of course I don’t mean putting a fusion reactor on an airplane. I know back to the future II was just a movie and Mr fusion probably won’t ever exist. Did somebody write stupid on my head while I was asleep last night or what? :p

          The energy from the sun may be free but the gigantic facilities required to gather solar thermal energy are not. Commercial scale fusion has the potential to provide much more power in a much smaller footprint and overall be much more economical especially in areas where it’s not sunny most of the time. Said power in the form of thermal energy can be used to split water into components and then be utilized in the production of liquid fuels.

  2. I don’t think Cerium will be any problem: it’s used for catalysts in cars to clean up the exhaust fumes.

    It’s a pretty awesome process and indeed, you do want to remove all the oxygen. You don’t want to know the explosive power of oxygen with hydrogen ;)

  3. I love this type of stuff. There is some good research going on with algae — but this is a good pathway also — again if you can get the reaction going. I for one would have no problem if an extra say $1 or $2 went straight into this research and was added on to a tax for flight. Either pay research into this now, or pay more later.

  4. What’s wrong with the age-old chlorophyll assisted conversion of water and carbon dioxide into organic matter. Like growing algae and converting them to fuel?

    1. Agreed. It’s cool that we’re developing a way to make hydrocarbons out of thin air using some giant solar-powered megareactor, but a bowl of algae can do the same thing at a much higher efficiency for a much lower cost.

      Give the scientists a few more years to tweak the genetics of the algae and they’ll be pumping out more kerosene than you can shake a stick at. A generation from now everything will be running off fuels produced in bioreactors (except for the electric cars that is).

      1. The issue as I understand it is those processes consume large quantities of fresh water a resource that isn’t in great abundance in the places where sunlight is intense enough to maximize algae growth. That plus having to separate fuel from what presents a problem.

        1. Algae grow in both fresh and sea water, pick the species that fits your water supply. They are looking (genetically modifying) for species with high fat content. Drain the excess water, mash the stuff and collect the biofuel that’s lighter than the water.

          And it does not need solid ground; it can be produced off-shore.

      2. “A few more years” has been the catchphrase for more than a decade. The problem is not so much creating the fuel but extracting it in a cost-effective manner, and that’s been the main catch for several years now. Currently, it’s done by crushing the algae to break open the cells and then filtering out the fuel, which still has significant water and other impurities. The algae then has to be grown all over again.

        I’m a fan of biofuels and I hope that someone comes up with a way to get around the limitations of algae and other mechanisms under research. But I think the Navy’s method, which basically involves a nuclear reactor to provide the energy, has more potential than anything from algae.

    1. And that should begin to tell you the energy costs of doing it. If you could use the solar energy efficiently and for free, that’d be one thing, but you can’t.

  5. Now if we could figure out how to incorporate salinated sea water into the process then we can use the extra 2.5-6.5 feet (.8-2m) increase in the global mean sea level.

  6. Given the fact that Shell has spent significant time in developing natural gas-to-liquid jet fuel mixture, it is safe to assume it is the only near term choice for an environmental friendlier fuel choice for jets. Using this Fischer-Tropsch Synthetic Paraffinic Kerosene reduces sulfur and particulates released into the environment. BioFuels are being researched as a more viable source of future energy needs since they can be developed in maritime facilities that do not consume the ever decreasing available lands for food production.

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