The California Air Resources Board (ARB) Low Carbon Fuel Standard (LCFS) staff has released for public comment four new Tier 2 renewable diesel (RD) pathways using soy oil, used cooking oil, tallow, and corn oil at the Diamond Green facility in St. Charles, Louisiana.
Diamond Green Diesel (DGD) uses the UOP Ecofining Process to produce RD from Used Cooking Oil (UCO), tallow, corn oil, and soybean oil. The Ecofining Process hydrogenates triglycerides and free fatty acid feedstocks which are then isomerized to create a high-quality hydrocarbon fuel. DGD has integrated operations with an adjacent oil refinery (Valero) to reduce the energy consumption and maximize the use of co-products and surplus energy.
(DGD is a joint venture between Diamond Alternative Energy LLC, a subsidiary of Valero Energy Corporation and Darling Ingredients to process recycled animal fat, used cooking oil, and other feedstocks into renewable diesel fuel.)
In addition to the renewable diesel (green diesel) the process produces a liquid petroleum gas vapor stream (LPG vapor); a liquid petroleum liquid stream (naphtha LPG); a purge gas stream; and a waste steam stream. All of these co-product streams go to the adjacent Valero refinery.
DGD purchases electric power, natural gas, and hydrogen from the refinery; the natural gas is used to produce steam and in direct heaters. The DGD plant receives two hydrogen streams from the refinery: a pure hydrogen stream and an H2S rich stream.
|Proposed Pathway Carbon Intensity (CI)|
|Fuel||Description||Carbon Intensity (gCO2e/MJ)|
|Direct Emissions||Indirect Land Use||Total (gCO2e/MJ)|
|Soy oil||Renewable Diesel produced from US Soybean, Fuel produced in Louisiana and transported to California||53.86||0||53.86|
|Used Cooking Oil||Renewable Diesel produced from US Used Cooking Oil, Fuel produced in Louisiana and transported to California||20.28||0||20.28|
|Animal Fat (Tallow)||Renewable Diesel produced from US Tallow, Fuel produced in Louisiana and transported to California||30.00||0||30.00|
|Corn Oil||Renewable Diesel produced from US Corn Oil, Fuel produced in Louisiana and transported to California||31.27||0||31.27|
DGD distributes their RD by various modes from the plant to various facilities in Central and Southern California. The three modes are ship, rail direct, and rail indirect (barge, rail, and truck). DGD uses the most conservative mode—rail indirect—to calculate the CI values of the RD.
Background. In 2009, the ARB approved the LCFS regulation to reduce the carbon intensity (CI) of transportation fuel used in California by at least 10% by 2020 from a 2010 baseline. The LCFS sets annual carbon intensity (CI) standards, which reduce over time, for gasoline, diesel, and the fuels that replace them. Under the current LCFS regulation, the 2020 standard of a 10% CI decline will also be imposed for all years post-2020.
Carbon intensity is expressed in grams of carbon dioxide equivalent per megajoule of energy provided by that fuel. CI takes into account the full lifecycle GHG emissions associated with a fuel: all of the steps of producing, transporting, and consuming a fuel.
For 2017, the average carbon intensity required for diesel is 98.44 gCO2e/MJ; the 2020 target is 91.81 g/MJ.