Waste to energy, landfill methane, waste to jet fuel

[lostnfound]

I’ve been reading about multiple uses of municipal solid waste (trash OR MSW.)
And about RIN credits for capturing methane.
And about feedstock options for jet fuel

What I’ve read is that MSW collectors make a lot of money from RIN credits they earn by capturing methane from their landfills, to incentivize them to collect the methane.

And I’ve learned that there is no feedstock to make carbon-neutral aviation fuel that is close to being available in large enough quantities to support current aviation demand, except maybe MSW. In technical reports (like a study produced by the NYNJPA) it shows MSW or cooking oil as being a source that is economically viable and carbon-reducing or far better than petroleum. Fulcrum in Reno is the first such MSW to SAF producer.

I am not sure if these reports show it as carbon-neutral solely because of avoided methane from landfills, and if so, are they recognizing that 50% or so is being captured, at least from large municipal landfills?

My logic.
1. Unless global aviation essentially ceases, it will keep burning jet fuel. Electric planes are not viable for commercial large aircraft because of an energy density problem.
2. The most viable feedstock seems to be MSW. To my uninformed eyes, it looks inevitable.
3. RIN credits earned by the capture of methane from landfills incentivize the reduction of harm from a particular landfill —but thus may also be DIS-incentivizing other options, like recycling or using MSW to generate SAF.
4. The more methane captured, the more RIN credits they earn. But this may incentivize an MSW mix that produces higher concentrations of methane for the sake of capture. (I read an article than describes carbon retention in MSW mix based on whether it includes or does not include food waste or yard scraps.)
5. It should be better to NOT have landfills than to have them, if only 50% of the methane is captured.

Anybody with some knowledge on these topics who can comment?

[Warpy]

1. Harvesting methane from landfills and sanitation facilities

is already happening in some places in the developing world, it's just not widespread, not yet. The systems being used are ridiculously cheap, piping methan into homes for cooking, saving people money they'd have spent on more expensive kerosene.

Here is one gram that is up and running, fueling an electrical plant plus large kitchen:

[eppur_se_muova]

2. Interesting thoughts, but perhaps better posted in Environment & Energy:

https://democraticunderground.com/?com=forum&id=1127

You'll find more appropriate expertise there.

[lostnfound]

3. Thank you, cross-posted at your suggestion.

https://www.democraticunderground.com/1127170235

I was also interested in the chemistry behind these questions — the Fischer Tropsch conversion that produces liquid fuels from bio stock; the energy derived from WtE plants — thinking there might be a theoretical chemical equation answer that would cut to the chase.

My post wandered off topic a lot!

[NNadir]

4. Fischer Tropsch is of course a topic worthy IMO of discussion by scientists.

The topic is, however, very broad.

The point you raise is a thermodynamic question. In general, under most conditions, practically all conditions, waste to energy wastes energy, but under certain circumstances this is justifiable.

Waste to energy programs using what might be "waste" heat, can actually recover some exergy from that heat, at least under conditions where high temperatures are involved.

As for E&E, thermodynamics is not a popular topic over at E&E; much of what is written there either deliberately ignores the topic or pretends it doesn't exist. In my view, after much experience with that forum, science is definitely not a "thing" there.