Aviation fuel has a trivial replacement in renewable biofuels, and three nontrivial replacements in liquid hydrogen combustion, liquid hydrogen fuel cells, and for short flights in battery power.
Biofuels as in from farming? Modern farming just turns oil into crops, so turning the crops back into oil is a non-solution. The only viable current biofuels work by turn leftover waste matter into fuel - in other words, recycling.
Also, any farming done for primary energy is farming not done for food.
Farming does not need to be that way. It's very amenable to electrification.
Long haul aviation needs high energy density.
You have heard critiques about farming that focus on very specific uses of corn and soybean under conventional American agribusiness, and while these are by no means the best biofuel feed stocks or the best harvesting methods, the low ROE is irrelevant if you are willing to feed in arbitrary quantities of cheap solar power to get precious liquid hydrocarbons out.
Flying contributes only 2.5% to global carbon emissions and it is one of the applications where hydrocarbons are least replaceable - bar hydrogen. It is dramatically easier to shift over anything that doesn't have to fight gravity, so flying will likely decarbonize last.
Maybe I'm just stupid but if all the planes in the world used biofuels, wouldn't that mean that flying is net-zero carbon (at least as it comes to fuel consumption)?
Like you do your flying, release CO2, but that CO2 gets captured again... I mean that doesn't sound bad, right?
It's not going to reduce the level of CO2 in the air right now, but it would stop further increases... which, mathematically, seems to be the same thing as if we kept the status quo and did something else to reduce CO2 output? What am I missing?
