EPA accepting comments on preliminary biomass sorghum analysis

By Erin Voegele | January 05, 2015

The U.S. EPA is accepting public comments on its preliminary analysis of the lifecycle greenhouse gas (GHG) emissions associated with the growth and transport of biomass sorghum for use as biofuel feedstock through Jan. 30.

On Dec. 31, the EPA published a notice in the Federal Register inviting the public to comment on its preliminary analysis of GHG emissions attributable to the growth and transport of biomass sorghum for use as biofuel feedstock. According to the EPA, the notice explains the agency’s analysis of the growth and transport components of the lifecycle GHG emissions from biomass sorghum and describes how the EPA may apply the analysis in the future to determine whether biofuels produced from biomass sorghum meet necessary GHG reductions required for qualification under the renewable fuel standard (RFS) program.

In the notice, the EPA indicates that the agency anticipates biofuels produced from biomass sorghum could qualify as cellulosic biofuel under the RFS if certain process technology conditions are met.

According to the EPA, it received a petition from the National Sorghum Producers requesting the agency evaluate the lifecycle GHG emissions of biofuels produced using biomass sorghum feedstock and provide a determination of which renewable fuel categories the resulting biofuels may be eligible for under the RFS. Within the notice, the EPA said that as an initial step in that process, it has conducted a preliminary evaluation of the GHG emissions associated with the growth and transport of biomass sorghum when used as a biofuels feedstock. The agency is seeking public comment on the methodology it used and the results of its preliminary evaluation. The EPA also specified it expects to revise its assessment as appropriate. The revised assessment would then be used to evaluate RFS fuel pathway petitions that propose to use biomass feedstock. In those pathway assessments, the EPA will consider GHG emissions associated with the use and transport of biomass sorghum, along with GHG emissions associated with the petitioner’s biofuel production process and GHG emissions associated with the transport and use of the finished biofuel.

Within the notice, the EPA indicates its analysis shows that on a per-dry-ton-of-feedstock basis, GHG emissions associated with biomass sorghum and use are similar those associated with the production and use of switchgrass. The EPA also addresses the wide variety of sorghum types, noting that for the purposes of this notice it considers biomass sorghum to be Sorghum bicolor that has been selected or bred to maximize cellulosic content and has at least 75 percent cellulosic content. Hybrids that are crosses of Sorghum bicolor and sudangrass are also considered to be biomass sorghum if they have 75 percent cellulosic content. Hybrids that are crosses of Sorghum bicolor and Johnsongrass (Sorghum halepense), however, are not considered to be biomass sorghum even if such hybrids have 75 percent or higher cellulosic content. Cultivars with an adjusted cellulosic content of less than 75 percent would be considered forage sorghum and would not be addressed by this notice.

While EPA’s analysis of switchgrass under the RFS assumed national average yields of approximately 4.5 to 5 dry tons per acre, with an expected increase to 6.6 dry tons per acre by 2022, the agency expects biomass sorghum yields to be much higher. According to the notice, based on field trials in nine states, the average yield of biomass sorghum was about 11 dry tons per acre in 2012. Yields are expected to increase to approximately 13 dry tons per acre in the southern U.S. by 2022.

Comments can be submitted online at Regulations.gov under Docket ID No. EPA-HQ-OAR-2014-0537. In addition, comments can be submitted via email, mail or hand delivery. Additional information on how to submit comments is available in the notice published on the Federal Register website.