Because POET operates a large number of corn ethanol plants that utilize a variety of production technologies, ARB staff approved the grouping of POET plants into a series of sub-pathways in its applications. This arrangement allows POET to receive approval for sub-pathways rather than for individual facilities.

POET has included four plants in its Sub-Pathway 7 proposal: Emmetsburg, Gowrie, Jewell, and Lake Crystal. Lake Crystal is located in Minnesota while the other three plants are located in Iowa. All are Midwest, dry mill, natural gas-fired plants that utilize the raw starch hydrolysis (RSH) fermentation process.

RSH is an enzyme-based method that reduces the amount of heat required during fermentation and eliminates the liquefaction and saccharification steps. RSH plants generally consume less energy per BTU of ethanol produced than do conventional facilities. The Sub-Pathway 7 facilities produce both wet and dry distiller’s grains with solubles (DGS).

Because the ratio of dry DGS (DDGS) to wet DGS (WDGS) varies over time at Sub-Pathway 7 plants, POET is seeking separate 100% DDGS and 100% WDGS pathway carbon intensities (CIs). If, in a given production period, 95% of the DGS is dried, 95% of the ethanol produced would receive the DDGS CI and the remaining 5% would receive the WDGS CI. Together, the four Sub-Pathway 7 plants produce approximately 247 million gallons of ethanol annually.

POET is applying for a 100% dry DGS carbon intensity (CI) of 89.76 gCO₂e/MJ and a 100% wet DGS CI of 81.41 gCO₂e/MJ. These values are lower than the corresponding reference pathway CIs from the LCFS Lookup table: two Midwestern, natural-gas-fired, pathways. These pathways differ only in terms of DGS moisture content: the dry DGS reference pathway has a CI of 98.40 gCO₂e/MJ while the wet DGS CI is 90.10 gCO₂e/MJ.

POET’s sub-pathways achieve lower CI values relative to the reference pathways through reductions in energy consumption.

Pursuant to Regulatory Advisory 10-04, upon posting on the LCFS website, this pathway and its associated carbon intensity value may be used for reporting and credit generation purposes prior to adoption and incorporation into the LCFS regulation.