Flying a Passenger Jet with Solar Power? Yes, We Can Do that Now

Philipp Furler is a scientist working at the ETH university in Zurich. As this article at EurekAlert explains, he and his team have come up with a clever new way to make jet fuel from solar power, water and CO2 extracted from air.

The process requires high temperatures of around 1,500 degrees Celsius. That’s about three times the usual operating temperature for concentrated solar power (CSP) projects. But it can be done. It’s just a question of adding some more mirrors.

It works by using a “reticulated ceramic structure” built of “Ceria”. I don’t exactly understand this, but I trust these experts that they know what they are talking about. My layperson grasp of this is:

Ceria is the equivalent of CO2 with Cerium (Ce) instead of Carbon (C). So the formula is Ce2O.

Turns out that if you heat it up to 1,500 degrees Celsius, some of the oxygen is released (and can be used as a valuable byproduct). Then introduce water (H2O) and CO2 and watch the Ceria suck off oxygen, resulting in a stream of hydrogen and CO (carbon monoxide). That mixture is also called syngas. From there on it is a trivial exercise to refine it into kerosene by a process called Fischer-Tropsch known since 1925.

The article mentions that Furler just founded a startup called “Sunredox”. It still flies under the radar, with zero hits on a Twitter search right now and no homepage for the company found on the first page of a Google search.

The process is more expensive than just using oil. Furler hopes that a high CO2 price will flip that disadvantage. And he wants to get the oil industry involved, since they have the necessary experience with large-scale projects.

Let’s just note that while a CO2 tax helps, the same result (higher oil prices) can be achieved by effectively limiting oil production. Think OPEC with teeth and ambition.

And while a high CO2 tax may be perceived as not in the interest of the oil industry, a high oil price certainly is. I recall having pointed this out occasionally on this blog.

The other part in flipping would come from getting the cost of this process down. There is probably still much potential to do so, since it is still just out of the laboratory.

A third way for cost to come down is to have more CO2 in the air, making it cheaper to extract. The world seems to be on track to help a lot with that over the coming decades.

The article’s headline is “Desert solar to fuel centuries of air travel”. Using desert areas makes sense since you have few cloudy days there and the real estate is extremely cheap. You would also like to have easy access to water, so an ideal location would have excellent solar resources and be close to an ocean.

Turns out that the “Eastern Province” of Saudi Arabia is where most of the oil is. Conveniently it has a big desert area and direct access to the Persian Gulf. People living there are familiar with the merits of selling fossil fuels to the world. They also need to think about what to sell once the oil runs out in a couple of decades. Making jet fuel from ocean water and air should be in their interest.

This is still very early days for this technology. The equivalent of December 2009 for the Bitcoin project.

But this process is certainly more effective and cheaper than waiting another 5 million years until new oil forms in the usual geological process.

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