So it does exist, requires no retrofit up to 20% biodiesel, and with minor retrofit can go to pure BD, but it congeals around 45°f so some amount of petroleum as a stabilizer is required for winter heating. Apparently ethanol from corn does not produce more energy than is required to create it, but biodiesel already being partly made for another purpose and otherwise wasted brings its creation energy down a lot.
I’m back from the Internet with knowledge to share!
https://www.northeastbiodiesel.com/heating-with-biodiesel
So it does exist, requires no retrofit up to 20% biodiesel, and with minor retrofit can go to pure BD, but it congeals around 45°f so some amount of petroleum as a stabilizer is required for winter heating. Apparently ethanol from corn does not produce more energy than is required to create it, but biodiesel already being partly made for another purpose and otherwise wasted brings its creation energy down a lot.
Even ethanol critics don’t claim ethanol needs more energy to make than it produces. However the most optimistic supports only give in around 1.7x.