Where to get BioDiesel?

[AMD_IS_THE_BEST]

@Mk4 30R

bio is fine. running grease is where you need heaters and filters, etc.
grease requires you start on diesel, then switch to grease.

but rather than run around to get BioD, you can just use an additive with regular ULSD.

Whats an acceptable additive and where to obtain it?