In the decade before the current and planned proliferation of renewable diesel, the incumbent industry’s use of waste fats, oils and greases (FOG), along with distillers corn oil (DCO), had been trending steeply upward. Pre-RD, more than half of all U.S. biodiesel production facilities had gained the ability to process FOG inputs and, quite readily, DCO, as a majority of the fleet was multi-feedstock capable well before blueprints for renewable diesel were drawn up in earnest.

For better or worse, however, our industry does not abide by a first come, first serve feedstock policy, especially for inputs traditionally defined as low-cost and low-quality. So, as renewable diesel production opens its seemingly limitless budget to the procurement of FOG—and specifically used cooking oil (UCO)—as well as DCO and other low-carbon intensity (CI) byproducts, vast quantities of it will no doubt be drawn into the orbit of our industry’s new branch, with its mega refineries buying big, paying like clockwork and never sleeping. 

The feedstock at the center of renewable diesel’s precipitous rise—not by volume, but CI desirability—is UCO, which makes up just a tenth of the nation’s biomass-based diesel production but 90% of the hype around it. The excitement around UCO, though, is not without merit. The byproduct of restaurant fryer grease is in ultra-high demand this summer, and its price has jumped dramatically during the past year, not just because of renewable diesel production, but mostly. Our cover story, “Renewable Diesel Backs Into UCO,” explains why UCO is one of renewable diesel’s most wanted feedstocks; it also explains where UCO is collected, and how its aggregated, authenticated and sold. The story lends perspective on why UCO collectors and traders, while appreciative of biodiesel, enjoy doing business with the industry’s voracious, deep-pocketed takers.

Despite the intense new demand for UCO and DCO, renewable diesel producers are not exclusively using these inputs for production, of course. Doing so would be desirable from a CI perspective (i.e., attaining optimum California LCFS value per gallon), but it would be impractical logistically for a 500-million-gallon per year plant. Rather, most big renewable diesel facilities are simply supplementing fresh soybean oil with other feedstocks like DCO and UCO—which is quite inconsistent in quality. Meanwhile, the draw of renewable diesel production, and the higher prices its creating for waste oils, is pulling an array of marginal feedstocks into the production pool. Just characterizing poor-quality inputs is challenging enough, never mind preparing the product for a renewable diesel plant’s hydrotreater. In “Getting It Renewable Ready,” we talk to a few of the leading pretreatment technology providers about what it takes to identify, prep and purify these tough-to-process feedstocks for renewable diesel.     

Finally, be sure to check out our Spotlight stories on Sam Carbis Solutions Group LLC and BDI-BioEnergy International GmbH—companies in different lines of work in different places, but both uniquely engaged in the industry’s newest phase of growth.