What’s in a name? Two fuels, two processes, two different names, one goal

JEFFERSON CITY, Mo. — Renewable diesel. Biodiesel. Potayto. Potahto?

When it comes to terminology, words matter and when it involves two very separate fuels, Scott Fenwick, technical director for Clean Fuels Alliance America, wants to make sure the public knows the difference.

“In the technical community, biodiesel and renewable diesel are two distinctly different fuels. When I read headlines and when I am reading articles, often the words ‘biodiesel’ and ‘renewable diesel’ get thrown out interchangeably,” he said.

For the people making them, using them and promoting them, the two fuels are very different fuels, made through separate processes.

“Biodiesel is relatively easy to make, through a process called trans esterification. We could make it on a tabletop, it’s really not complicated,” Fenwick said.

“Pretty simple ingredients, you need a fat or oil or grease as a feedstock, an alcohol and a catalyst and you end up with biodiesel, which is an oxygenated fuel.

“That is important because it lends it some of the combustions properties and lower carbon benefits, and you have crude glycerin as a byproduct.”

Renewable diesel is made through a process similar to that used to produce petroleum diesel.

“The process is called hydrotreating. The same process is used in a petroleum refinery to produce diesel fuel, but you are using a renewable biomass fat, oil or grease,” Fenwick said.