With the explosion in production of renewable diesel, yellow grease and corn oil are cutting into soybean oil’s position as the dominant feedstock for biomass-based diesel fuel, said three agricultural economists.
“The recent shift toward tallow and the longer-term shift towards yellow grease and corn oil make sense given the relatively low carbon intensity (CI) scores given to renewable diesel made from these feedstocks in the California LCFS (low carbon fuel standard) program.”
The lower CI scores translate into higher dollar credit values per gallon, wrote the economists at the farmdoc daily blog. More than 80 percent of renewable diesel produced in the country is consumed in California.
“Turning to the future, it is important that projections of total biomass-based diesel feedstock usage consider the very different composition of feedstock usage for … biodiesel versus renewable diesel,” wrote Maria Gerveni and Scott Irwin of the University of Illinois and Todd Hubbs of the USDA. “Renewable diesel feedstock usage is more skewed towards low CI feedstocks, such as yellow grease, and as renewable diesel production increases in the future, this will continue to skew the overall growth of biomass-based diesel feedstock volume towards feedstocks with lower CI scores.”
Soybean oil accounts for 42 percent of all feedstocks for biodiesel and renewable diesel, the two fuels that make up the larger category of biomass-based diesel. Soy oil’s share was nearly 48 percent at the start of this decade, when the renewable diesel boom began. Yellow grease’s share is now 20 percent, up 4 points. Yellow grease encompasses vegetable and animal fats and oils, including used cooking oil.
For renewable diesel, yellow grease is the largest feedstock at nearly 29 percent, while soy oil is 27 percent, and corn oil is 15 percent.
Soy oil is undisputed among feedstocks for biodiesel, accounting for 57 percent of usage. However, production of biodiesel has fallen in recent years while renewable diesel as skyrocketed.