3 ms·

The Air Force has proven a system that uses renewable energy to power a system that combines water and carbon dioxide extracted from the air to produce E-Jet sy

by mike_d 5y ago

The Air Force has proven a system that uses renewable energy to power a system that combines water and carbon dioxide extracted from the air to produce E-Jet synthetic fuel. Currently a chemically similar but less environmentally sound synthetic fuel is approved to be mixed 50/50 with regular JP8 in military aircraft and they are doing acceptance testing for full synthetic. This effectively takes every high efficiency jet engine and makes it carbon neutral, with the added benefit that you don't need to ship the fuel anymore. At that point electric planes are dead. https://www.afmc.af.mil/News/Article-Display/Article/2820003/air-force-partners-with-twelve-proves-its-possible-to-make-jet-fuel-out-of-thin/ https://www.afmc.af.mil/News/Article-Display/Article/2820003...

jillesvangurp 5y ago
That's one of several possible fuels. What all of those have in common is that they are more expensive than kerosine, which in turn is more expensive than electric. The big advantage of battery electric is cost. Wherever you can fly them, it will be the cheapest way to do it, by far.
- ncmncm 5y ago
  Costs change. Cost of synfuels will only come down, as solar electric continues to do.
genewitch 5y ago
How do you get the CO2 out of the air, other than the obvious "grow corn"?
- ncmncm 5y ago
  Seriously? Adsorb it. You have to move a lot of air through your system, but that just costs energy. With solar cost still in free fall, it will soon be cheaper to get CO2 out of the air, add hydrogen extracted from water, and deliver CH4 or larger molecules, than to get them out of the ground.
  - genewitch 5y ago
    is adsorbing something i can do at home or does it require something on the scale of a refinery?
    - thereisnospork 5y ago
      To do so practically requires scale, but a science fair-worthy demo can probably be done at home, perhaps using distilled water as the sorbent.
- toomanybeersies 5y ago
  There's a few options out there, the most common method is solvent absorption [1]. There's also a YC backed startup, Prometheus Fuels, that's trying to commercialise a process using carbon nanotube membranes for CO2 separation [2]. [1] https://web.archive.org/web/20130508220516/http://www.uk-shec.org.uk/uk-shec/news/IEEE_Paper_6_3_5_finalx1x.pdf https://web.archive.org/web/20130508220516/http://www.uk-she... [2] https://prometheusfuels.com/ https://prometheusfuels.com/
- thereisnospork 5y ago
  Using a sorbent, to absorb the CO2 in preference to N2/O2/Ar (etc.). The 'sorbed CO2 is then de-sorbed in a closed container (for compression, storage, etc.). Selexol is a common commercial solvent for CO2 removal, though for atmospheric removal other tech may be preferable.

by mike_d 5y ago

jillesvangurp 5y ago

That's one of several possible fuels. What all of those have in common is that they are more expensive than kerosine, which in turn is more expensive than electric. The big advantage of battery electric is cost. Wherever you can fly them, it will be the cheapest way to do it, by far.

ncmncm 5y ago
Costs change. Cost of synfuels will only come down, as solar electric continues to do.

genewitch 5y ago

How do you get the CO2 out of the air, other than the obvious "grow corn"?

ncmncm 5y ago
Seriously? Adsorb it. You have to move a lot of air through your system, but that just costs energy. With solar cost still in free fall, it will soon be cheaper to get CO2 out of the air, add hydrogen extracted from water, and deliver CH4 or larger molecules, than to get them out of the ground.
- genewitch 5y ago
  is adsorbing something i can do at home or does it require something on the scale of a refinery?
  - thereisnospork 5y ago
    To do so practically requires scale, but a science fair-worthy demo can probably be done at home, perhaps using distilled water as the sorbent.
toomanybeersies 5y ago
There's a few options out there, the most common method is solvent absorption [1]. There's also a YC backed startup, Prometheus Fuels, that's trying to commercialise a process using carbon nanotube membranes for CO2 separation [2]. [1] https://web.archive.org/web/20130508220516/http://www.uk-shec.org.uk/uk-shec/news/IEEE_Paper_6_3_5_finalx1x.pdf https://web.archive.org/web/20130508220516/http://www.uk-she... [2] https://prometheusfuels.com/ https://prometheusfuels.com/
thereisnospork 5y ago
Using a sorbent, to absorb the CO2 in preference to N2/O2/Ar (etc.). The 'sorbed CO2 is then de-sorbed in a closed container (for compression, storage, etc.). Selexol is a common commercial solvent for CO2 removal, though for atmospheric removal other tech may be preferable.