Guidance on Qualifying an Analytical Method for Determining the Cellulosic Converted Fraction of Corn Kernel Fiber

This document provides updated guidance on how to demonstrate that an analytical method for determining the cellulosic converted fraction of corn kernel fiber co-processed with starch to produce cellulosic ethanol at a traditional ethanol facility satisfies the applicable regulatory requirements. Public confidence in the volumes of cellulosic ethanol produced under the Renewable Fuel Standard (RFS) program is important to the integrity of the program. As such, affected stakeholders have sought clarification regarding what methods EPA will accept for determining the cellulosic converted fraction.

This updated 2022 guidance benefits from recent scientific advancements, including work conducted by the Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL), to develop a public method that addresses the analytical concerns identified in the 2019 guidance. The guidance also includes consideration of recently released reference materials by the National Institute of Standards and Technology (NIST). Based on the availability of the NREL method and the NIST reference materials, this updated guidance describes three additional ways companies might satisfy the registration requirements.

2022 Guidance Document (pdf) (September 2022, EPA-420-B-22-041)

2019 Original Guidance Document (PDF) (May 2019, EPA-420-B-19-022)