Also, a catalyst only speeds up a reaction. It does not change the thermodynamics of a reaction. An irreversible reaction with the addition of a catalyst is still irreversible.
This is a very poor article. The very first sentence is already wrong: "It could lead to net zero emissions for air travel."
No, it can't. Aviation has a variety of emission sources, which include not only CO2, but also others like nitrous oxides and water vapour, which creates contrains and impacts cloud formation. There's huge uncertainty how large these effects are, but they're significant.
It's not particularly surprising that you can turn CO2 into jet fuel. The issue is: It's not a complete fix for aviation's climate problem and the efficiency is extremely low. The amount of electricity needed is enormous.
Key takeaways: Aviation CO2 emissions are 2%, but overall emissions are somewhere between 3 and 7%. And using E-Fuels to power future aviation (with current growth projections) requires more electricity than all the electricity that is genreated today.
I feel like the article was clear that this was just a step in a potential direction, not a full solution, and they explicitly said this wasn't even a viable for a single flight as of yet.
If anyone comes up with a "complete fix", I'm all for it - in the meantime, looking into partial fixes to at least improve our situation sounds like a good idea to me.
I think the key takeaway from the laws of thermodynamics is that we can pull all the CO2 out of the air once we have fusion power. Before that point, it's not going anywhere.
Tidal power is from the initial formation of the solar system.
Geothermal is a roughly 50-50 mixture of the initial formation heat of the Earth’s creation and the decay of radioisotopes in the core. (I was going to add something about the crystallisation of liquid outer core onto the surface of the solid inner core, but Wikipedia implies that’s not a big source of heat).
Yes, and those energy are very mineral intensive and the current number of new installation per year need to triple to avoid creating new coal or gas plants altogether. Is it sustainable?
And i agree, fusion is at least 50 years away of a working ITER unless a breakthrough in supraconductor is done
Yes. Unlike coal, oil, and natural gas — which are dug out of the ground and burned — the stuff you dig out of the ground to make PV and wind turbines can be recycled into more PV and wind turbines when the products reach end-of-life.
> water vapour, which creates contrains and impacts cloud formation. There's huge uncertainty how large these effects are, but they're significant.
Water vapor emissions aren't cumulative in the same way as CO2. It would be potentially an impact of what ever level of air travel you have, but it wouldn't accumulate over time like carbon emissions, and so could be sustainable if air travel is held at a fixed level.
This headline is fake news. As the nature link says, there is already alot of past work for decades in this technology.
The reasearch paper only studied existing catalysts and measured their efficiency.
> In this investigation, we report the preparation of iron-based catalysts using the Organic Combustion Method (OCM) and determined their catalytic performance
I don't believe carbon emissions will be "solved" by global altruism or even government regulation. This is something that will have a technological solution.
Carbon sequestration from the atmosphere is not a hard problem and turning atmospheric carbon into fuel is not a hard problem. It just makes no sense to burn fossil fuels to do it. This is a net energy loss although there's still a market for turning inconvenient energy sources into convenient ones.
But as soon as the energy source is cheaper than fossil fuels, the equation completely changes.
This, to me, is the ultimate promise of renewables.
It may well be the promise of fusion too but I'm not yet convinced fusion will ever be commercially viable. I'm least convinced about Tokamak reactors. New designs may prevail. Fusion is attractive because of the abundance of the fuel but the problems of containment (eg turbulence), alpha particle embrittlement and neutron embrittlement remain... huge. Stars contain all this with gravity.
To a large extent the equation is already flipping. Solar and wind are getting cheaper every year and will decisively beat fossil fuels on a dollar per watt basis eventually.
I believe we need to go faster than what is economically feasible because according to the IPCC we are on track to a +4C world by 2100 where a +2C change will already lead to catastrophic consequences for civilization.
Government regulation and individual altruism is necessary, but not sufficient, to solve the emissions problem. There are other tools though. Government incentives can change the economics to make necessary changes happen faster. For example California's cap and trade system has enabled new business opportunities, which reduce climate change. There are companies that make money by gathering old refrigerant and incinerate it to sell carbon offsets because of cap and trade. https://gimletmedia.com/shows/howtosaveaplanet/kwhnz8b
Yeah but only using lots of land (more than it would require to run a solar powered electrified transport system) or using lots of energy and money (conservative guesstimate 50% of world GDP where air travel account for ~2% of CO2e emissions).
That approach requires lots of land, water, and time. Nothing wrong with that, but much of the funding for CO2->jet fuel research comes from the military, which wants to be able to create liquid fuel quickly from CO2 in the atmosphere and they don't care how inefficient it is. Military customers are typically not very interested in processes that require running a farm.
The military also spends a lot of time turning jet fuel into electricity, because the former is energy-dense, easy to store, easy to transport. And they need electricity in lots of places without a grid.
Where would the reverse be useful? Somehow you have unlimited electricity but no fuel, and you have time and space to run a chemical refinery? (And isn't carbon capture from the atmosphere likely to require farm-scale infrastructure anyway?)
You cannot run aircraft on electricity; liquid fuel is the only option. The military is keenly interested in being able to refuel aircraft in situations where liquid fuel shipments might be denied or unavailable for some reason.
You can't in any practical sense. Locomotives don't have a problem carrying the weight of a diesel engine plus a generator; in fact the extra weight works in their favor.
If you tried that trick with an airplane it would never get off the ground. Locomotives use this system not for efficiency but because they need the low-end torque electric motors provide. (If they only needed efficiency they'd just drive the wheels with the diesel engine directly.) Airplanes don't need torque; they need power.
You can run an airplane on batteries but only for a few minutes with modern battery technology. Practical battery-powered aircraft for military applications are not going to happen any time soon. We might see battery-powered air taxis soon but those are not even close to meeting military requirements for fighters, transports, etc.
> [For] large passenger aircraft, an improvement of the energy density by a factor 20 compared to li-ion batteries would be required
The time it takes to surpass this energy density threshold is affected by battery tech investments; which had been comparatively paltry in terms of defense spending. Trillions on batteries would've been a much better investment; with ROI.
Sadly, some folks in defense still can't understand why non-oil investments in battery tech are best for all.
There are multiple electric trainer aircraft with flight times over an hour and quite a few more in development.
Jet engines are terribly inefficient (30-50% efficient) compared to electric motors.
The team heated a mix of citric acid, hydrogen and an iron-manganese-potassium catalyst to turn CO2 into a liquid fuel capable of powering jet aircraft. ... The lab method only produced a few grams of fuel
I like how 5 days ago we had ; " Could Carbon Dioxide Be Turned into Jet Fuel? " [0] and after some HN users decided to investigate for 120 hours we have this ^
>"Wired reports that Oxford University scientists have successfully turned CO2 into jet fuel, raising the possibility of conventionally-powered aircraft with net zero emissions.
The technique effectively
reverses the process of burning fuel
by relying on the organic combustion method. The team heated a mix of citric acid, hydrogen and an iron-manganese-potassium catalyst to turn CO2 into a liquid fuel capable of powering jet aircraft.
The approach is inexpensive, uncomplicated and uses commonplace materials. It’s cheaper than processes used to turn hydrogen and water into fuel."
36 comments
[ 2.1 ms ] story [ 104 ms ] threadThey call it 'renewable' yet use Iron as a catalyst. I'm not a chemist - how is that renewable?
No, it can't. Aviation has a variety of emission sources, which include not only CO2, but also others like nitrous oxides and water vapour, which creates contrains and impacts cloud formation. There's huge uncertainty how large these effects are, but they're significant.
It's not particularly surprising that you can turn CO2 into jet fuel. The issue is: It's not a complete fix for aviation's climate problem and the efficiency is extremely low. The amount of electricity needed is enormous.
Worthy read (title is about hydrogen, but it also covers e-fuels quite a bit): https://www.cleansky.eu/news/hydrogen-powered-aviation-prepa...
Key takeaways: Aviation CO2 emissions are 2%, but overall emissions are somewhere between 3 and 7%. And using E-Fuels to power future aviation (with current growth projections) requires more electricity than all the electricity that is genreated today.
If anyone comes up with a "complete fix", I'm all for it - in the meantime, looking into partial fixes to at least improve our situation sounds like a good idea to me.
Solar and wind are the result of the solar radiation which comes from fusion.
Tidal power is from the initial formation of the solar system.
Geothermal is a roughly 50-50 mixture of the initial formation heat of the Earth’s creation and the decay of radioisotopes in the core. (I was going to add something about the crystallisation of liquid outer core onto the surface of the solid inner core, but Wikipedia implies that’s not a big source of heat).
And i agree, fusion is at least 50 years away of a working ITER unless a breakthrough in supraconductor is done
Yes. Unlike coal, oil, and natural gas — which are dug out of the ground and burned — the stuff you dig out of the ground to make PV and wind turbines can be recycled into more PV and wind turbines when the products reach end-of-life.
> water vapour, which creates contrains and impacts cloud formation. There's huge uncertainty how large these effects are, but they're significant.
Water vapor emissions aren't cumulative in the same way as CO2. It would be potentially an impact of what ever level of air travel you have, but it wouldn't accumulate over time like carbon emissions, and so could be sustainable if air travel is held at a fixed level.
The reasearch paper only studied existing catalysts and measured their efficiency.
> In this investigation, we report the preparation of iron-based catalysts using the Organic Combustion Method (OCM) and determined their catalytic performance
Bad link I guess.
Carbon sequestration from the atmosphere is not a hard problem and turning atmospheric carbon into fuel is not a hard problem. It just makes no sense to burn fossil fuels to do it. This is a net energy loss although there's still a market for turning inconvenient energy sources into convenient ones.
But as soon as the energy source is cheaper than fossil fuels, the equation completely changes.
This, to me, is the ultimate promise of renewables.
It may well be the promise of fusion too but I'm not yet convinced fusion will ever be commercially viable. I'm least convinced about Tokamak reactors. New designs may prevail. Fusion is attractive because of the abundance of the fuel but the problems of containment (eg turbulence), alpha particle embrittlement and neutron embrittlement remain... huge. Stars contain all this with gravity.
I believe we need to go faster than what is economically feasible because according to the IPCC we are on track to a +4C world by 2100 where a +2C change will already lead to catastrophic consequences for civilization.
Government regulation and individual altruism is necessary, but not sufficient, to solve the emissions problem. There are other tools though. Government incentives can change the economics to make necessary changes happen faster. For example California's cap and trade system has enabled new business opportunities, which reduce climate change. There are companies that make money by gathering old refrigerant and incinerate it to sell carbon offsets because of cap and trade. https://gimletmedia.com/shows/howtosaveaplanet/kwhnz8b
https://archive.today/h0bYu
https://www.total.com/media/news/press-releases/total-and-am...
Still not commercially viable, but much closer to it than the linked process.
Where would the reverse be useful? Somehow you have unlimited electricity but no fuel, and you have time and space to run a chemical refinery? (And isn't carbon capture from the atmosphere likely to require farm-scale infrastructure anyway?)
Locomotives run on electrical energy produced by diesel generators (because electric motors are more energy efficient), for example.
The limits are the cost and weight of the batteries and the charge time.
If you tried that trick with an airplane it would never get off the ground. Locomotives use this system not for efficiency but because they need the low-end torque electric motors provide. (If they only needed efficiency they'd just drive the wheels with the diesel engine directly.) Airplanes don't need torque; they need power.
You can run an airplane on batteries but only for a few minutes with modern battery technology. Practical battery-powered aircraft for military applications are not going to happen any time soon. We might see battery-powered air taxis soon but those are not even close to meeting military requirements for fighters, transports, etc.
> [For] large passenger aircraft, an improvement of the energy density by a factor 20 compared to li-ion batteries would be required
The time it takes to surpass this energy density threshold is affected by battery tech investments; which had been comparatively paltry in terms of defense spending. Trillions on batteries would've been a much better investment; with ROI.
Sadly, some folks in defense still can't understand why non-oil investments in battery tech are best for all.
There are multiple electric trainer aircraft with flight times over an hour and quite a few more in development.
Jet engines are terribly inefficient (30-50% efficient) compared to electric motors.
Wasn't this on HN a few days ago?
https://news.ycombinator.com/item?id=25517512
The advantages are obvious - a nuclear carrier could make fuel for its aircraft and potentially its escorts too. Wonder how this is getting along.
[0] ; https://news.ycombinator.com/item?id=25517512
The technique effectively
reverses the process of burning fuel
by relying on the organic combustion method. The team heated a mix of citric acid, hydrogen and an iron-manganese-potassium catalyst to turn CO2 into a liquid fuel capable of powering jet aircraft.
The approach is inexpensive, uncomplicated and uses commonplace materials. It’s cheaper than processes used to turn hydrogen and water into fuel."