What are the downsides of Aviation SAF? In Brazil we have cars that work with ethanol. Ethanol increases the engine power, but the car has just 70% of autonomy.
Yeah, "autonomia" (autonomy) is used to describe a cars range in Portuguese where we would normally use "range".
My car has zero autonomy. It's fine.
ethanol fuel, by itself, doesn't increase engine power. Ethanol allows the use of higher compression-ratios/increased ignition-timing/higher air-density than typical petroleum tunes due to lessened chance of detonation.
Only one: a lack of availability/scale and consequent cost.