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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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