CycleFlorida

FedEx announced their operations will be carbon neutral by 2040.
I thought this was an impossible goal. I can see all ground equipment complying, but am dubious about the aircraft.
Could this be part of their plans?

FedEx Commits to Carbon-Neutral Operations by 2040
https://newsroom.fedex.com/newsroom/sustainability2021/

rickair7777

Airlines really mean they are going to buy carbon offsets (ie pay somebody to plant trees, etc), not that they are going to actually stop burning jet A. In theory that should work, but the eco-freaks don't really care for the idea.

123494

I’m so tired of all this environmental bull crap. I enjoy increasing my carbon footprint.

rickair7777

There's that.

Excargodog

Why not? They’ve bough in to stupider ideas than that...

https://www.politico.com/news/magazi...olitics-477620

rickair7777

Carbon offsets, if they worked, might dilute the narrative of tearing down the establishment and society in the interest of a great reset and social justice for all (except of course the winners from the old paradigm, who will be severely punished).

Excargodog

Don’t know that THAT would be a realistic concern. If anything it might increase the albedo a little, reflecting solar energy back up and decreasing global warming. But in any event, it’s difficult to see where a combustion product of water would be worse than a combustion product of water, CO2, oxides of Sulfur, Oxides of Nitrogen, unburned fuel, and soot, which are the products of combustion of Jet A.

rickair7777

Water and CO2 have different absorption spectra... water vapor lets some light through, and absorbs some light which becomes heat. Then the light that got through reaches the ground and heats it. The ground then radiates IR back up, and water vapor absorbs IR pretty well, so that stays in the biosphere as heat.

There's a graph in this article:

https://jpenhall.wordpress.com/2012/...-water-vapour/

Carbon-neutral SAF might actually be better for global warming than H2.

Also considering the stoichiometric process Jet A combustion produces only C02 and water vapor. The other pollutants are the results of impurities or catalytic processes involving atmospheric N2.

An H2 combustion of an equivalent amount of O2 would produce more H2O than Jet A and zero carbon... so while you're reducing the carbon you emit more H2O than before so now that's significant for greenhouse purposes. The other pollutants need to be considered too of course, but there's no equation to compare/contrast C02 vs. smog pollution... that's in the eye of the beholder.

rower

"What is the Disadvantage of Hydrogen Fuel Cells?

Hydrogen Extraction
Despite being the most abundant element in the Universe, hydrogen does not exist on its own so needs to be extracted from water via electrolysis or separated from carbon fossil fuels. Both of these processes require a significant amount of energy to achieve. This energy can be more than that gained from the hydrogen itself as well as being expensive. In addition, this extraction typically requires the use of fossil fuels, which undermines the green credentials of hydrogen."

Source: https://www.twi-global.com/technical...gen-fuel-cells

Those who claim that hydrogen is the future of fuels for: "trains, planes and automobiles" do not know physics and chemistry.

rickair7777

I've done some homework on this, since it seemed pretty far-out for airbus...

I was right. The genesis of this "project" is that it was actually a condition imposed on airbus by some euro-politicians (who are probably not physicists or engineers).

The fine print is that airbus expects longer-range aircraft will still require conventional liquid fuel of some sort (presumably SAF) due to the energy density limitations of H2.