Biodiesel, old technology, older than refining oilYes, biodiesel is a thing, has been for decades. I have gotten it for heating oil-but it really doesn't like the cold.
I have no idea what sort of witch's brew they concocted to keep it liquid at -40 (the usual method to keep biodiesel from gelling it to add regular diesel and/or K1 to it), but I'm sure it's nothing close to actual cooking oil.