CloudHound wrote:I see the initials SAF being used a lot recently.
Sustainable Aviation Fuel which appears to offer a level of improvement in environmental emissions.
Maybe not a long term solution which I think involves hydrogen, electricity and Flubber.
Now that is an interesting topic (and declaring an interest, I'm on one of the sub-committees of the Prime Minister's JetZero Council, which is pursuing this).
SAF is both an excellent idea, and a really bad one, depending upon the way in which you look at it.
The principle being applied (and I'm not a total convert to this) is that we should be able to produce from a multiplicity of sources, drop-in Jet-A1 replacements, that will allow air transport to carry on as previously with minimal change to their operations. That might just work too, and HMG is investing 8-figure sums in developing that capability over the next year or two alone.
My problems with it are several:-
(1) The science is pretty much telling us now that about 2/3rds of air transport's contribution to radiative forcing (the mechanism behind climate change) isn't CO2 it's contrails. Now SAF *may* also reduce that, and statements to that effect are being made, but the evidence to prove those statements is very weak.
(2) Noise, surface pollution, other emissions won't change.
(3) Agriculture is very far from carbon neutral itself.
There's a holy grail, being seriously pursued now, of e-Fuels, which is basically the use of renewable electricity to scrub CO2 from the atmosphere, and reconstitute it as burnable jet fuel. This has actually been done, but at laboratory scales, and costs ~10-20 times per volume of fossil fuels. But, it's a really interesting trajectory.
None of which solves the contrail problem, the real solutions to that come primarily from better meteorology, linked into air traffic management.
I really do like the direction of green hydrogen, then hydrogen burning or fuel cell aircraft. People like ZeroAvia are definitely creating a significant part of the future, if not all of it.
@johnm firstly I'm deeply jealous of your ten acres of trees, secondly I can absolutely see how that might make you carbon negative. My understanding incidentally is that it's not trees themselves that do most of the heavy lifting of carbon capture and storage, it's the build up of soil beneath them, made up of organic matter, and trapped in place by the presence of the trees.
G
I am Spartacus, and so is my co-pilot.