What is Renewable Diesel?
Renewable diesel (RD) is an emerging replacement fuel for today’s heavy-duty diesel engines. It is chemically identical to conventional (fossil) diesel fuel, but RD is produced from 100 percent renewable feedstock and contains no fossil carbon. This makes RD a potentially low greenhouse gas (GHG) alternative to conventional diesel. Moreover, RD is a “drop-in” diesel substitute. It can be produced in the same facilities as conventional diesel; transported, stored and dispensed in the same existing network; and combusted in the same engines.
It is important to note that RD is not “biodiesel.” While these two biofuels use similar feedstock, they differ in production and use characteristics. RD can be produced through multiple processes; the predominant pathway is to hydrotreat fats, oils and esters. Biodiesel is solely produced through esterification of fats and oils. RD is free of the ester compounds found in biodiesel, and it has a much lower aromatic content. An important advantage of RD is that it has no “blend wall.” Unlike biodiesel, high-level blends of RD (including 100 percent) are approved for use in diesel engines by most heavy-duty engine manufacturers. And, as further described below, the use of RD in diesel engines provides important environmental benefits compared to both conventional diesel and biodiesel.
Production of RD for US Transportation Markets
RD is produced using various renewable feedstock that include palm oil, palm fatty acid distillate (PFAD; a byproduct from the physical refining of palm oil), tallow (ie, rendered animal fat), and used cooking oil. Neste (formerly Neste Oil) is currently the world’s largest RD producer. Neste makes approximately 680 million RD gallons per year at its worldwide facilities (Finland, the Netherlands, and Singapore). Approximately half of this is exported to U.S. markets. Currently, U.S. production of RD is about 200 million gallons per year.