HPR is animal rendering based biodiesel. It doesn't have the high pressure polymerization issues vegetable based biodiesel does.

The issue with Bio isn't that is 20%, its there is no standardization for what makes up biodiesel. Soy, cellulose, algae, fat, etc and they all perform differently. My 617 for example, runs like a dog turd on cellulose bio (with even as little as B5), indeterminable from diesel other than smell on soy, and far better than diesel on HPR.