[jbaumg]

I am involved in this project. The aim is to built a demonstration plant to show the feasibility of the process and to develop a blueprint for larger plants that can produce sustainable jet fuel economically. Producing sustainable fuels is always more expensive than fossil fuels. However, upcoming legislation and taxation (at least in the EU) will change this equation.

Someone mentioned an efficiency of around 50% in a post here and resulting pricing, that's a fairly good estimate of the overall process and what is discussed as achievable cost for renewable synthetic fuels in general. The process is in this demonstration plant is Fischer-Tropsch. Using CO2 from an industrial point source is more efficient; however, it has potential legislative issues when it comes to certification of sustainable fuels, emission certificate trading... it's a fairly complicated topic. In addition, worldwide potential for lowest renewable energy costs does not correlate necessarily with existing CO2 point sources. That's why direct air capture makes a lot of sense.

Whether CCS is a better solution depends on renewable electricity pricing vs. the CCS costs, public acceptance and feasibility at the location of a plant. These vary strongly depending on where you are in the world. In many parts of Europe there is strong opposition to it as it may prolong the exploitation of fossil sources.

[mogadsheu]

Finally, an expert! I’m not, although I’ve been involved in energy for a while now.

I believe the Germans made synfuels towards the end of WWII using Fischer Tropsch when they were running low on conventional fuels. What tech is new about this project, besides the energy source?

[dredmorbius]

Germany, during WWII, and South Africa's SASOL since the 1970s:

https://www.netl.doe.gov/research/Coal/energy-systems/gasifi...

[jsilence]

Two decades and some ago a german company named Choren also produced SunDiesel in a similar process. They shut down this line of work quite some time ago. Not feasible.

[jabl]

They made synfuels from coal, which contains a lot of, uh, coal. So no need to capture it from the air. They didn't worry about CO2 pollution back then.

[dredmorbius]

For fuel synthesis, you have two principle processes: carbon sourcing, and actually sythesizing the fuel.

Once you've got the coal sourced, most of the rest of the WWII process is directly applicable to modern carbon-capture methods.

[happosai]

> Using CO2 from an industrial point source is more efficient; however, it has potential legislative issues when it comes to certification of sustainable fuels, emission certificate trading... it's a fairly complicated topic.

I can imagine! Considering lots of the co2 in air has fossil fuel origin, not putting the co2 capturing at a high volume co2 source seems rather dim. Regulators gonna regulate!

Maybe site the direct air capture in the middle of a german industrial city with coal plants all around...

[madaxe_again]

Or even better, at an airport. Then you have nil transportation cost for delivery too.

[juliangoldsmith]

Something like this could create a large market for CO2. If the market was hot enough, fossil fuel plants might capture and sell their own emissions.

[jjoonathan]

Is the intent to economically compete with biofuel, which also gets its carbon from the atmosphere, or is there a specific niche targeted by direct CO2 capture approaches?

[anovikov]

But efficiency of 50% is great! What's even the problem about it?

Say, an average price of base load electricity of 43.26EUR/MWh in Germany in 2018 (and that is a very pricey market - country which has a shitload of renewable power) - will result, at 50% efficiency, of energy feed costs of 3.07EUR per gallon of fuel. That's only 1.7x the actual cost of jet fuel in EU as per IATA (https://www.iata.org/publications/economics/fuel-monitor/Pag...).

You should add the capital cost of device itself, but if it's used round the clock, it shouldn't add so much. And if it's not, electricity can be almost free because a lot of the time, renewable power is in excess and can be purchased from the high voltage grid for very cheap (if we are speaking of high throughput industrial units which will probably have hundreds of megawatts connected, and will plug into high voltage grid directly).

All in all, it may get fuel 2x more expensive but it's not such a big deal.

[mirimir]

Simplistically, isn't this basically using the carbon from CO2 as a "carrier" for PV hydrogen? There's certainly a substantial efficiency hit. But there are also substantial challenges to displacing aviation fuel with hydrogen.

But then, it's also arguable that PV hydrogen is itself a "carrier" for PV electricity. So then the alternative is batteries. As much as I love electricity, I doubt that battery technology will ever achieve the energy densities of hydrocarbon fuels.

[dredmorbius]

More or less, yes.

Straigh molecular hydrogen is brutally difficult to work with. It is hard to store (high pressures and/or low temperatures), bulky, embrittles metals, and is violently explosive.

Synthetic analogues of fossil fuels (kerosene, petrol) are chemically virtually identical to what we've been using for the past century of powered flight (and should actually be cleaner/purer). There are few unknowns, safety is quite high, and the storage, handling, and combustion properties are well-understood and excellent for the application.

Powering FT fuel synthesis via photovoltaic or other solar processes could certainly work.

[pcl]

The article mentioned that the costs were high, but didn’t actually have any numbers. What do you expect the prototype’s efficiency to look like? What does that mean for the price of a liter of syngas? And how do you expect that to scale for larger plants?

[ourlordcaffeine]

I work in energy. With the rise of renewables, it is becoming more and more common that there are periods of insanely low or even negative spot energy prices.

Is it planned that the plant will be able to take advantage of low spot prices?

[joe_the_user]

What is the potential to do this kind of process intermittently, to take advantage of excess energy produced by solar and wind plants during certain periods.

[tempestn]

It wouldn't be expected to be cost effective, because there's also the capital cost to consider. Once you've built the plant, you basically need to run it as much as possible in order to recoup the investment.

[Stevvo]

Why do you target Jet fuel/aviation specifically?

After all, there isn't so much special about Jet A: I figure a PT-6 could run just fine on automotive diesel.

[jabl]

Land and sea transportation can much more easily shift towards other energy carriers such as batteries. Or using electric trains instead of trucks, etc. For ships even nuclear propulsion might be an option if the CO2 price rises enough.

Aircraft, not so much. Liquid hydrocarbons have amazing energy density, both by weight and volume, and in aircraft that matters a lot.

[macspoofing]

Be honest, isn't carbon capture a big distraction and was only mentioned for the media.