Scientists turn CO2 into jet fuel
engadget.com
engadget.com
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.
> 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.
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.
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
The advantages are obvious - a nuclear carrier could make fuel for its aircraft and potentially its escorts too. Wonder how this is getting along.
Wasn't this on HN a few days ago?
They call it 'renewable' yet use Iron as a catalyst. I'm not a chemist - how is that renewable?
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."
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.
Bad link I guess.
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