Summary	of	Interagency	Working	Comments	on	Draft	Language	under	

EO13563	Interagency	Review.		Subject	to	Further	Policy	Review.

Comments on U.S. Environmental Protection Agency’s final rule titled, “Regulation of Fuels and Fuel 

Additives: RFS Pathways II, and Technical Amendments to the RFS Standards and E15 Misfueling 

Mitigation Requirements,” RIN 2060-AR21. 

EPA RESPONSE TO OMB COMMENTS

Cellulosic content of feedstock greater than 75% 

QUESTION #1

Will EPA clarify whether this threshold also applies to corn kernel fiber or any other feedstock that may 

have some corn starch content? If for example, 25% of corn kernel fiber’s content were corn starch, 

then this would mean that all of the ethanol produced from that starch would qualify as cellulosic 

biofuel? 

EPA Response: Under the cellulosic content threshold approach, fuels made from feedstocks 

that EPA determines meet this minimum 75% cellulosic content threshold will be eligible to 

generate cellulosic biofuel RINs for the entire fuel volume produced, so long as the producer’s 

registration demonstrates their production process has the ability to convert cellulosic 

components. 

This includes crop residues such as corn kernel fiber, which has an average adjusted cellulosic 

content of 87%. Based on available data, the actual amount of starch that adheres to corn 

kernel fiber after separation from the rest of the corn kernel is typically less than 5 percent of 

the total mass of the separated corn kernel, which we believe is a de minimus amount. While 

EPA has determined that corn kernel fiber meets the 75% cellulosic content threshold, only corn 

kernel fiber that has been separated from the starch and is being processed into ethanol 

separately will be eligible to generate cellulosic biofuel RINs for the entire fuel volume 

produced. If corn kernel fiber is processed simultaneously with the corn starch (in situ), 

producers will not be able to allocate cellulosic RINs for any non-cellulosic portion of the 

feedstock. Rather, they will need to determine how much of the fuel is derived from the 

cellulosic components (e.g., through a mass balance calculation) and allocate cellulosic and noncellulosic RINs as required by the existing regulations at 1426(f)(3).

QUESTION #2

EPA’s compiled data on cellulosic feedstock concentrations in Table 2 of the draft memo to the docket 

titled, “Cellulosic Content of Various Feedstocks,” indicates that corn kernel fiber has an average of 87% 

cellulosic material. Does this mean that any corn starch that would be left in the corn kernel fiber that 

would be converted to biofuel could count as cellulosic or as corn ethanol? 

EPA Response: No. As described in Question #1, if corn kernel fiber is processed simultaneously, 

producers will not be able to allocate cellulosic RINs for any non-cellulosic portion of the 

feedstock. Rather, they will need to determine how much of the fuel is derived from the 

cellulosic components (e.g., through a mass balance calculation) and allocate cellulosic and noncellulosic RINs as required by the existing regulations at 1426(f)(3). 
Summary	of	Interagency	Working	Comments	on	Draft	Language	under	

EO13563	Interagency	Review.		Subject	to	Further	Policy	Review.

Where the corn kernel fiber is separated from the starch and converted to biofuel separately, 

there may be some small amount of remaining starch that adheres to the corn kernel fiber. As 

noted below, on average only 3.5% of separated corn kernel fiber is starch. The remaining 

material is protein and lipids. We consider the amount of corn starch adhering to the separated 

corn kernel fiber to be a de minimis amount. If some small amount of starch is converted into 

biofuel it would be eligible to generate RINs. We are adding clarifying language to the preamble 

that if a producer fails to use best efforts to separate adhering corn starch in an attempt to 

boost production of cellulosic biofuel from processing corn kernel fiber, the adhering starch will 

not be considered a de minimis contaminant, and the entire batch of resulting fuel will not be 

considered derived from crop residue and will not qualify as cellulosic biofuel.

Further, while EPA has sought to minimize excessive or burdensome compliance, new 

registration and record keeping requirements for cellulosic fuel producers have been 

established to allow EPA to identify irregularities in cellulosic fuel production. Specifically, EPA is 

requiring cellulosic producers to report the expected overall fuel yield for each of their 

feedstocks at registration, and to calculate and report the overall fuel yield for each batch of fuel 

produced. Taken together with the new ongoing testing and reporting requirements for the 

cellulosic converted fraction (new tests and calculations are to be reported annually or every 

500,000 cellulosic RINs – whichever comes first), this information will allow EPA to identify 

processes that are generating more cellulosic RINs than can be expected given the reported 

process data.

QUESTION #3

Did EPA specify any mass balance or other verification provisions in the regulatory text that would 

differentiate any biofuel produced from corn starch contained in corn kernel fiber or any other corn 

based feedstock?

EPA Response: As described in our response to question #1 above, there are provisions in the 

regulatory text requiring producers processing corn kernel fiber in situ to use reasonable 

analytical methods (e.g., a system specific material balance) to quantify the portion of the 

finished fuel attributable to the starch and cellulose respectively (§ 80.1451 (b)(1)(ii)(U). The 

regulatory framework requires the cellulosic converted fraction (cellulosic CF) to be obtained 

using a reasonable analytical method approved during registration, and further requires the CF 

to be recalculated at prescribed intervals or fuel volume based trigger points using the same 

calculation method approved at registration. Specifically, § 80.1451 (b)(1)(ii)(U) requires 

producers processing corn kernel fiber in situ to calculate the cellulosic converted fraction on an 

annual basis or upon generating every 500,000 gallons of cellulosic fuel. If the cellulosic 

converted fraction is different than previously calculated, the formula used to generate RINs 

must be updated. Under § 80.1451 (b)(1)(ii)(U) producers processing corn kernel fiber in situ

must also notify EPA within 5 business days and adjust the formula used to generate RINs if the 

cellulosic Converted Fraction deviates from the previously calculated value by 10% or more. 

EPA also prepared and included in the docket, a memo outlining various analytical methods for 

calculating the cellulosic CF, and provided an example RIN attribution calculation for a 

hypothetical in situ process producing ethanol from both corn starch (non-cellulosic) and corn 

kernel fiber (cellulosic) simultaneously.
Summary	of	Interagency	Working	Comments	on	Draft	Language	under	

EO13563	Interagency	Review.		Subject	to	Further	Policy	Review.

QUESTION #4

EPA states in Table 5 of the “Cellulosic Content of Various Feedstocks” draft memo that the average 

cellulosic content ranged from 75% to 92%. What is the reason for choosing 75% over some other 

percentage up to 92%?

EPA Response: This approach minimizes burdens and streamlines program implementation for 

both cellulosic biofuel producers and EPA. This simplified implementation provides incentives 

for production of fuels that are 75% or greater in cellulosic content. EPA believes this 

percentage, which is well over a 50% or “majority” value, is sufficiently significant to allow full 

qualification. A higher percentage would require accounting for a progressively small noncellulosic portion of the feedstock and therefore result in regulatory and administrative burdens 

on the use of feedstocks which are predominantly cellulosic. This figure is within EPA’s exercise 

of discretion to reasonably interpret the Clean Air Act and consistent with the objective that fuel 

made from feedstocks that are predominantly cellulosic are able to generate cellulosic biofuel 

RINs for their entire fuel volume. Based on interagency feedback, EPA has added additional 

language to sections IV.A.2, IV.A.3, and IV.A.4.c further supporting this rationale and clarifying 

how the threshold will be implemented. 

 Renewable electricity for electric vehicles from landfill biogas

QUESTION #5

For the 636 landfill biogas projects that are currently operating, how will EPA verify that the biogas that 

is currently being converted to electricity is being used by vehicles? Where in the preamble and 

regulatory text is this described?

EPA Response: EPA outlined new provisions related to registration, reporting and recordkeeping 

for the electricity and CNG/LNG pathways in the preamble (section IV.C of the preamble and §

80.1426 and § 80.1454 in the regulations). These provisions allow for the use of signed affidavits 

to prove the use or sale of renewable electricity and renewable CNG/LNG for transportation 

purposes. It is assumed that these affidavits would be signed by fleet managers or vehicle 

operators, verifying the use of the renewable transportation fuel. These affidavits would then 

be matched, by the registered fuel producer, to the delivery or sale of an equivalent amount of 

qualifying renewable electricity or renewable CNG/LNG. While it is impossible to track the 

specific molecules or electrons, producers must show that it is theoretically feasible that the fuel 

produced can reach the vehicle using it. 

QUESTION #6

If the landfill biogas is already being converted to electricity for use in the transportation sector, how 

would this meet the 50% GHG reduction requirements?

EPA Response: We do not think it is appropriate to differentiate between new plants and plants 

that converted to flaring after enactment of these regulations. Since landfills that currently have 

gas-to-energy projects in place at one point either replaced flaring with a gas-to-energy project 

or installed a gas-to-energy project as an alternative to the minimal compliance route of flaring, 
Summary	of	Interagency	Working	Comments	on	Draft	Language	under	

EO13563	Interagency	Review.		Subject	to	Further	Policy	Review.

we proposed and are finalizing treating the emissions from these landfills compared to the same 

flaring baseline.

Further, the calculated lifecycle GHG emissions are attributed to the energy equivalent 

electricity that displaces a corresponding energy equivalent volume fossil derived transportation 

fuel. The emissions from the energy equivalent electricity generated via the biogas-to-electricity 

pathway are more than 60% less than the energy equivalent emissions attributed to the 

baseline fossil fuel (2005 gasoline baseline). The lifecycle GHG emissions analysis performed by 

EPA applies broadly to electricity produced from waste derived biogas, and can be applied to 

landfill biogas that is already being converted to electricity for use in the transportation sector 

as well. The assumptions and boundary conditions used for this analysis are presented in a 

memo to the docket. 

 

 Treatment of corn starch that adheres to corn kernel fiber after separate from DDG

QUESTION #7

In the memo to the docket titled, “Cellulosic Content of Various Feedstocks,” EPA indicates that on 

average 87 percent of corn kernel fiber is cellulosic material and that 13 percent is other organics. EPA 

defines other organics as including starch. Does EPA know what portion of the 13 percent was identified 

as being starch? 

EPA Response: On average the other organic material consists of 3.5% starch, 5% protein, and 

5% lipids.

QUESTION #8

In the preamble section titled, “Treatment of Corn Starch that Adheres to Corn Kernel Fiber...,” EPA 

states that more recent and refined data better represents the current methods of starch-fiber 

separation. What does the new data indicate concerning the percentage of starch that still adheres to 

the corn kernel after separation from DDG?

EPA Response: In the preamble of the NPRM for this rulemaking, EPA stated that starch might 

compose up to 20 percent of the separated mass used to produce corn kernel fiber ethanol via a 

separate stream, based on data from 1998. Through the public comment process, we received 

more recent and fine-grained data that better represents current methods of starch-fiber 

separation. Based on this newer data, we believe the actual amount of starch that adheres to 

the fiber after separation from the rest of the corn kernel is on average 3.5% of the total mass of 

the separated corn kernel fiber feedstock. Based on interagency feedback, EPA has added 

additional clarifying language to the preamble.

QUESTION #9

Will all biofuel produced from corn kernel fiber feedstock be qualified cellulosic material based on the 

provisions in the rule regarding the minimum threshold of 75 percent cellulosic material? For corn 

kernel fiber feedstock, is there anything in the regulatory text that would prohibit biofuel producers 

from producing cellulosic biofuel even if 25 percent of the corn kernel fiber consists of corn starch? 
Summary	of	Interagency	Working	Comments	on	Draft	Language	under	

EO13563	Interagency	Review.		Subject	to	Further	Policy	Review.

EPA Response: See responses to questions 1 and 2. 

QUESTION #10

For the corn kernel fiber feedstock pathway, is there any periodic mass-balance or other requirements 

in the rule that would require the biofuel producer to verify that the starch content of corn kernel fiber 

is de minimis? 

EPA Response: See responses to questions 2 and 3. 

 Small Refinery 

QUESTION #11

How many small refineries/refiners qualified for the exemption in 2006 based on the 75,000 bpd 

threshold? 

EPA Response: 57

QUESTION #12

If the provision were evaluated for each year in isolation and not for all years back to 2006, how many 

refiners would qualify for the exemption in 2013 (or the most recent year that production data is 

available) based on the 75,000 bpd threshold?

EPA Response: EPA does not collect data on the actual crude capacity of refineries nor is this 

information publically available. We are aware of one facility that has exceeded the 75,000 bpd 

threshold since 2006, from the company’s 10k financial report. We anticipate that two 

additional refineries will exceed the threshold (one this year and one next year) due to recently 

completed expansion projects at the respective facilities.

 

QUESTION #13

If the provisions as written were to go into effect, how many more gallons of ethanol would need to be 

blended into transportation fuel? Would the change in this exemption require the blending of ethanol 

in biofuel that was previously E0 and how would this effect the blend wall? 

EPA Response: Granting or denying RFS hardships has no impact on EPA’s assessment of the 

capacity of the industry to produce and blend renewable fuels. Where we grant relief for an 

individual refinery from the cost of RFS compliance, we still conclude that overall the volumes 

they produce will be part of the fuel pool including the ability to blend gasoline to the E10 level.

The key difference between granting or not granting relief is not whether or not renewable fuels 

will be produced, blended and RINs separated, but rather which parties will need to retire those 

RINs in order to demonstrate compliance with the RFS program.