The Renewable Fuel Standard (RFS):
An Overview
Updated January 27, 2022
Congressional Research Service
https://crsreports.congress.gov
R43325

The Renewable Fuel Standard (RFS): An Overview

Summary
The Renewable Fuel Standard (RFS) requires U.S. transportation fuel to contain a minimum
volume of renewable fuel each year. The RFS—established by the Energy Policy Act of 2005
(P.L. 109-58; EPAct05) and expanded in 2007 by the Energy Independence and Security Act (P.L.
110-140; EISA)—began with requiring 4 bil ion gal ons of renewable fuel in 2006 and was
scheduled to ascend to 36 bil ion gal ons in 2022. The Environmental Protection Agency (EPA)
has statutory authority to determine the annual volume requirements after 2022.
The total renewable fuel statutory annual target consists of both conventional biofuel and
advanced biofuel. Since 2014, the total renewable fuel statutory target has not been met with the
advanced biofuel portion fal ing below the statutory target since 2015. In short, EPA set the total
renewable fuel volume below the statutory amount—using its waiver authority—mainly due to
underproduction of advanced biofuels. Should the proposed 2020, 2021, and 2022 renewable fuel
volume requirements be finalized, the United States wil not have met the total renewable fuel
target as outlined in statute for the RFS for 2014 through 2022—the last nine years (i.e., the latter
half) of the program’s statutory annual requirements.
EPA administers the RFS and is responsible for several related tasks. For instance, using the
statutory criteria EPA evaluates which renewable fuels are eligible for the RFS program. Also,
EPA establishes the amount of renewable fuel that refiners and importers must account for in the
coming year based on the statutory targets, fuel supply, and other conditions, and the EPA
Administrator can exercise waiver authorities to reduce volumes if necessary. Further, the statute
requires that the EPA Administrator “reset” the RFS—modifying volumes required for future
years—if certain conditions are met. EPA also monitors compliance for the RFS using a system of
tradable credits referred to as renewable identification numbers (RINs).
Congress has expressed ongoing interest in various facets of the RFS, including smal refinery
exemptions; RFS compliance; EPA approval of fuel pathways (e.g., renewable electricity); EPA’s
proposal to reduce the 2020 through 2022 requirements; how EPA could use its “reset” authority
to determine post-2022 requirements; and how the program performs overal (e.g., environmental
effects), among other things. For years, some in Congress have debated various aspects of the
RFS, including program management, transparency, and certainty. Further, there have been
repeated efforts by some Members to either amend or repeal the RFS, while other Members have
acted to maintain the status quo.
In December 2021, EPA published a proposed rule for the RFS volume requirements for 2020,
2021, and 2022 that contains a number of actions. For example, EPA proposes to reduce the
previously finalized volume requirements for 2020 (for al fuel categories except biomass-based
diesel) and to set 2021 and 2022 volume requirements below the statutory targets. EPA reports
that “significant and unanticipated events” (e.g., the COVID-19 pandemic) led, in part, to the
proposed 2020 volume reduction. This would mark the first time that EPA has proposed to reduce
a volume requirement that was previously finalized. The proposed rule adds a supplemental
volume of 500 mil ion gal ons of total renewable fuel—split between 2022 and 2023—to address
a court remand of the 2016 final volume requirement. Other actions in the proposed rule include
the treatment of biointermediates, the treatment of confidential business information (CBI), and
defining “produced from renewable biomass” in the Code of Federal Regulations for the RFS.
Legislation has been introduced that would prohibit the EPA Administrator from reducing a
volume requirement that was finalized (S. 3380). Conversely, some Members of Congress have
requested that the EPA Administrator waive or significantly reduce the 2020 volume requirement,
and set the 2021 and 2022 volume requirements at “levels that comport with reality.”
Congressional Research Service

link to page 12 The Renewable Fuel Standard (RFS): An Overview

Introduction
Established by Congress as an amendment to the Clean Air Act, the Renewable Fuel Standard
(RFS) mandates that U.S. transportation fuels contain a minimum volume of renewable fuel.1 The
mandated minimum volume increases annual y and general y has been met using both
conventional biofuel (e.g., corn starch ethanol) and advanced biofuel (e.g., cel ulosic ethanol).
For a renewable fuel to be applied toward the mandate, it must be used for certain purposes (i.e.,
road transportation fuel, jet fuel, or heating oil) and meet certain environmental and biomass
feedstock criteria.
The statute outlines annual volume requirements—listed in tables—for four fuel categories: total
renewable fuel, total advanced biofuel, cel ulosic biofuel, and biomass-based diesel. The total
renewable fuel statutory volume required for any given year equates to the sum of conventional
biofuel (which is unspecified in statute) and advanced biofuel (which is specified in statute).2
Both cel ulosic biofuel and biomass-based diesel are subcategories of advanced biofuel (both of
which are specified in statute). There is also a third advanced biofuel category—other advanced
biofuels (which is unspecified in statute).3
The statutory volume requirements for both total renewable fuel and total advanced biofuel for
the RFS have not been met since 2013. The Environmental Protection Agency (EPA)
Administrator has the authority to waive the statutory RFS requirements, in whole or in part, if
certain conditions outlined in statute occur.4 EPA has used this waiver authority multiple times to
reduce the volumes obligated parties must blend into transportation fuel. For instance, the 2020
targets set by EPA for total renewable fuel and for total advanced biofuel were approximately
67% and 34% of the statutory targets, respectively.5 A variety of factors, such as infrastructure
limitations, technological development, and limited federal assistance, have contributed to
chal enges in meeting the total volume requirement established by Congress. These chal enges
have included a lack of cel ulosic biofuel production and delays by the EPA in approving fuel
pathways.6 Oil prices, consumer demand for transportation fuel, and circumstances related to the
COVID-19 pandemic from the last few years may also contribute to the chal enges in meeting the
more recent total statutory volume requirements.
However, two fuel categories consistently have met their statutory targets: conventional biofuel
(which has an implied target) and biomass-based diesel (which has an explicit target).7 Also, since
2014, two advanced biofuel pathways—renewable compressed natural gas and renewable

1 42 U.S.C. §7545(o).
2 Conventional biofuel equates to the difference between the total renewable fuel category and the advanced biofuel
category.
3 Other advanced biofuel is computed by subtracting both the cellulosic biofuel category and the biomass-based diesel
category from the total advanced biofuel category.
4 For more information, see CRS Report R44045, The Renewable Fuel Standard (RFS): Waiver Authority and
Modification of Volum es, by Kelsi Bracmort .
5 U.S. Environmental Protection Agency, “Renewable Fuel Standard Program: Standards for 2020 and Biomass-Based
Diesel Volume for 2021 and Other Changes,” 85 Federal Register 7016, February 6, 2020.
6 For an explanation and discussion of fuel pathways, see t he “Administering Agency” section of this report.
7 U.S. Environmental Protection Agency, Public Data for the Renewable Fuel Standard Data, January 5, 2022.
Obligated parties have until March 31 to submit annual compliance reports for the prior year. See 40 C.F.R.
§80.1451(a)(1).
Congressional Research Service

1

The Renewable Fuel Standard (RFS): An Overview

liquefied natural gas—have constituted the majority of the cel ulosic biofuel volume requirements
as finalized by EPA.8
A multitude of factors affect the conditions under which the RFS operates—some external to RFS
policy and some internal. The impact of these factors can be chal enging to quantify. For
example, it is not clear how implementation of the RFS wil have adapted to changes in gasoline
consumption in response to fluctuating crude oil and gasoline prices, rising feedstock prices, and
a global event like the COVID-19 pandemic.9 It is not clear how agricultural trade issues impact
biofuel policies or the commodities used to produce biofuel.10 It is also uncertain how the
program wil fare given EPA’s intent to implement the “reset” provision of the statute, which
al ows the agency to modify the volumes required for future years if certain conditions are met.11
Chal enges to implementing the RFS have led to scrutiny of the program in Congress and to
litigation about EPA’s regulations.12 Largely due to concerns about the implementation and
feasibility of the RFS, some Members of Congress have expressed their perspectives on EPA’s
rulemakings as wel as EPA’s implementation of the program.13 They also have questioned
whether to amend or repeal the RFS or whether to maintain the status quo.14 This report provides
an overview of the RFS, including some of the widely discussed policy issues related to it.15
The Statute
The RFS was established by the Energy Policy Act of 2005 (P.L. 109-58; EPAct05).16 It was
expanded in 2007 by the Energy Independence and Security Act (P.L. 110-140; EISA) (see the

8 Ibid. EPA defines renewable compressed natural gas as biogas or biogas-derived pipeline quality gas that is
compressed for use as transportation fuel and meets the definition of renewable fuel. EPA defines renewable liquefied
natural gas as biogas or biogas-derived pipeline quality gas that goes through the process of liquefaction in which it is
cooled below its boiling point, and which meets the definition of renewable fuel. See 40 C.F.R. §80.1401.
9 For more information, see Energy Information Administration, Crude Oil Demand Returns Faster Than Supply,
Increasing Prices and Reducing Inventories, November 9, 2021; Energy Information Administration, Agricultural
Feedstock Costs Drive RIN Prices to All-Tim e Highs, June 2, 2021; and Energy Information Administration, COVID-
19 Mitigation Efforts Result in the Lowest U.S. Petroleum Consum ption in Decades, December 30, 2020.
10 For more information on agricultural trade issues, see CRS Report R46653, Major Agricultural Trade Issues in the
117th Congress, coordinated by Anita Regmi.
11 T he statute granted EPA the authority to “reset” the RFS given certain conditions starting in 2016. EPA proposes to
“reduce the applicable statutory volumes for 2020, 2021 and 2022 utilizing both the cellulosic waiver and reset
authorities.” U.S. Environmental Protection Agency, “Renewable Fuel Standard (RFS) Program: RFS Annual Rules,”
86 Federal Register 72445, December 21, 2021.
12 Since 2010, there have been numerous congressional hearings about the RFS. Additionally, there have been multiple
legal challenges regarding EPA’s administration of the RFS. In some cases, courts have found against EPA’s rules for
various reasons; in others, courts have affirmed EPA’s authority.
13 See, for example, Sen. Joni Ernst, “Ernst Slams Biden’s Move to Slash Demand for Biofuel, Break Campaign
Promises,” press release, December 7, 2021; and Sen. Shelley Moore Capito, “Capito: EPA Intends to Inflict More
Harm on Small Refiners,” press release, December 7, 2021.
14 Legislation has been introduced in the 117th Congress that would repeal, amend, or further support the RFS (see, for
example, H.R. 5701, S. 2385, H.R. 5376). For a brief discussion about potential legislative reform for the RFS, see
CRS In Focus IF10842, The Renewable Fuel Standard: Is Legislative Reform Needed?, by Kelsi Bracmort .
15 For additional discussion, see CRS Report R40155, Renewable Fuel Standard (RFS): Overview and Issues, by Kelsi
Bracmort .
16 More specifically, Section 1501 (Renewable Content of Gasoline) of EPAct05 amended Section 211 of the Clean Air
Act (CAA) by adding a Renewable Fuel Program. Section 1501 directed the EPA Administrator to ensure that gasoline
sold or introduced into commerce in the United States contained a minimum volume of renewable fuel. T his “ original”
2005 RFS required 4.0 billion gallons of renewable fuel for 2006, ascending to 7.5 billion gallons by 2012. T he amount
Congressional Research Service

2

The Renewable Fuel Standard (RFS): An Overview

text box in this section for a discussion of the differences between the 2005 RFS and the 2007
RFS). The RFS mandate requires that transportation fuels sold or introduced into commerce in
the United States contain an increasing volume of a predetermined suite of renewable fuels. The
statute required 4.0 bil ion gal ons of renewable fuel in 2006, ascending to 36.0 bil ion gal ons
required in 2022, with EPA determining the volume amounts after 2022 in future rulemakings.
The statute centers on four renewable fuel categories—total renewable fuel, advanced biofuel,
cel ulosic biofuel, and biomass-based diesel—each with its own target volume.17 A key part of the
statutory definition of each fuel category is whether the fuel achieves certain greenhouse gas
(GHG) reductions relative to gasoline and diesel fuel. Each fuel is assigned a lifecycle GHG
emission threshold (in proportion to baseline lifecycle GHG emissions for gasoline and diesel).18
The total renewable fuel requirement under the RFS is met with the combination of fuels from
two renewable fuel categories: conventional biofuel and advanced biofuel. The requirement for
advanced biofuel, in general, can be met with the combination of three types of advanced biofuel:
cel ulosic biofuel, biomass-based diesel, and other advanced biofuels. To date, the total annual
volumes required have been met mostly with conventional biofuel (e.g., corn starch ethanol).
Beginning in 2015, the mandate implicitly capped the conventional biofuel volume amounts
while increasing the requirement for advanced biofuels.19 For instance, the statutory RFS total
advanced biofuel requirement increases over time from approximately 7% of the total renewable
fuel requirement in 2010 to 58% of the total renewable fuel target in 2022.20
Differences Between the 2005 (“RFS 1”) and the 2007 (“RFS 2”) Laws
There are at least five major changes in the RFS as expanded in 2007 by EISA:

larger annual volume targets specified in statute for an extended period of time (i.e., through 2022),

the establishment of separate requirements for different classes of biofuels (e.g., cel ulosic, advanced),

the addition of greenhouse gas accounting requirements,

a different renewable biomass definition (as explained below), and

an expansion of EPA’s waiver authority to lower RFS volumes.

of renewable fuel was prescribed in EPAct05 for the years 2006 through 201 2. Beginning in 2013, the annual volume
of renewable fuel was to be determined by the EPA Administrator and the Secretaries of Agriculture and Energy.
Additionally, the RFS established in EPAct05 would have required that at least 250 million gallons of the renewa ble
fuel be derived from cellulosic biomass starting in 2013.
17 T he statute defines the four renewable fuels. Conventional biofuel is corn starch ethanol. Advanced biofuel is
renewable fuel, other than corn starch ethanol, with lifecycle greenhouse gas emissions of at least 50% less than
lifecycle greenhouse gas emissions from its gasoline or diesel counterpart. Cellulosic biofuel is renewable fuel derived
from cellulose, hemicellulose, or lignin that is derived from renewable biomass, with lifecycle greenh ouse gas
emissions of at least 60% less than lifecycle greenhouse gas emissions from its gasoline or diesel counterpart. Biom ass-
based diesel is biodiesel or other renewable diesel with lifecycle greenhouse gas emissions of at least 50% less than
lifecycle greenhouse gas emissions from its diesel counterpart. Additionally, biofuel from new facilities—those built
after enactment of the 2007 law—must achieve at least a 20% GHG reduction to qualify as a conventional renewable
fuel. New facilities are facilities that commence construction after December 19, 2007. 42 U.S.C. §7545 (o)(2)(A)(i).
18 For more discussion, see CRS Report R40460, Calculation of Lifecycle Greenhouse Gas Emissions for the
Renewable Fuel Standard (RFS), by Brent D. Yacobucci and Kelsi Bracmort .
19 Starting in 2015, the statute caps conventional biofuel at 15 billion gallons. From 2015 onward, the increase in the
total renewable fuel statutory target stems from the increase in the advanced biofuel statutory target.
20 Calculations include the annual mandate required by statute in 2007 and do not take into account EPA’s revision of
the biofuel mandates for 2010 through 2018.
Congressional Research Service

3

The Renewable Fuel Standard (RFS): An Overview

The renewable biomass definition for the RFS under EISA does not make the majority of woody biomass on
federal lands available for use as a renewable feedstock. Further, the 2007 RFS waiver authority directs the EPA
Administrator to set the annual standard for cel ulosic biofuels under the RFS for the fol owing year by November
30 of each year, and to lower the cel ulosic biofuel standard if projected U.S. production is less than the volume in
the statute. The 2007 RFS waiver authority also al ows the EPA Administrator to reduce the renewab le fuel and
advanced biofuel requirements of the standard, if the cel ulosic biofuel requirement is lowered.
Statutory Compliance
EPA regulates compliance with the RFS using a tradable credit system.21 Obligated parties
(general y, refiners and importers) submit credits—cal ed renewable identification numbers
(RINs)—to EPA for each gal on in their annual obligation.22 (Thus, general y, each gal on of fuel
produced to meet the obligation generates its own unique RIN.)23 In short, the annual obligation
for an individual refiner or importer, referred to as the renewable volume obligation (RVO), is the
obligated party’s total gasoline and diesel sales multiplied by the annual renewable fuel
percentage standards announced by EPA.24 The RVO is used by an obligated party to determine
how many RINs they are to submit to EPA at the end of a given year to be in compliance with the
mandate.
In short, the RIN lifecycle can be described in three steps:
1. a RIN is attached to a gal on of qualifying renewable fuel once that fuel is
produced,
2. the RIN is separated once the renewable fuel is blended with gasoline or diesel
fuel or used unblended, and
3. the separated RIN may be submitted for compliance, traded, or banked for future
use.
RINs are valid for use to demonstrate compliance in the year they are generated and the following
year.25 RINs may be used by the party that generates them or they may be traded with other
parties. The EPA Moderated Transaction System (EMTS) is used to register RIN transactions.

21 42 U.S.C. §7547(o)(5).
22 EPA defines an obligated party as any refiner that produces gasoline or diesel fuel within the 48 contiguous states or
Hawaii, or any importer of gasoline or diesel fuel into the 48 contiguous states or Hawaii during a compliance period.
A renewable identification number (RIN) is a unique 38-character number that is issued (in accordance with EPA
guidelines) by the biofuel producer or importer at the point of biofuel production or the port of importation. There are
five different RIN types which are assigned based on a fuel’s “ D-code” depending upon the specific type of fuel. For
more information, see CRS T estimony T E10026, Background on Renewable Identification Num bers under the
Renewable Fuel Standard, by Brent D. Yacobucci.
23 As will be discussed later in this section, some renewable fuels can generate more RINs per gallon of fuel.
24 T he statute requires the EPA Administrator to express the annual renewable fuel obligation in percentages. 42 U.S.C.
7545(o)(3). For the 2020, 2021, and 2022 proposed rule, EPA proposes a percentage standard range as EPA reports it
needs “to consider the impact of these [court] decisions on our SRE [small refinery exemptions] policy, and it is still
unclear at this time whether we will be granting SREs for 2020, 2021, or 2022, and if so, to what degree.” For 2022,
EPA reports the overall renewable fuel percentage standard range is 11.76 %-12.33%, the advanced biofuel percentage
standard range is 3.27 - 3.42%, t he biomass-based diesel percentage standard range is 2.42%-2.54%, and the cellulosic
biofuel percentage standard range is 0.44%-0.46%. U.S. Environmental Protection Agency, “ Renewable Fuel Standard
(RFS) Program: RFS Annual Rules,” 86 Federal Register 72439, December 21, 2021.
25 40 C.F.R. §80.1427(6)(i) in the EPA RFS regulations.
Congressional Research Service

4

link to page 11 The Renewable Fuel Standard (RFS): An Overview

An obligated party incurs a deficit if they are unable to submit enough RINs to meet their RVO
for that compliance period. An obligated party may carry a deficit due to a variety of reasons.
Obligated parties may carry a deficit from one year to the next, but in the year following the
deficit, the obligated party must meet compliance for that year’s renewable fuel volume
requirement and purchase or generate enough credits to satisfy the deficit from the previous
year.26
Different biofuels are not treated equal y within the RFS. The categories are nested within each
other, such that some fuels qualify for multiple categories (e.g., cel ulosic ethanol), while others
(mainly corn starch ethanol) may only be used to meet the overal RFS but not the advanced
category or its nested subcategories.27 For example, a gal on of cel ulosic biofuel may be used to
meet the cel ulosic biofuel mandate, the advanced biofuel mandate, or the total renewable fuel
mandate, possibly making it a more highly valued fuel.28
In addition, some biofuels generate more RINs per volume than others because of the difference
in the fuel’s energy content. This difference is accounted for by a metric referred to as the
equivalence value (EV) of the biofuel.29 The EV of a renewable fuel represents the number of
gal ons that can be claimed for compliance purposes for every physical gal on of renewable fuel
used, and it is general y the ratio of the energy content of a gal on of the fuel to a gal on of
ethanol. For example, because biodiesel has an EV of 1.5 when being used as an advanced
biofuel, 1,000 physical gal ons of biodiesel would equal 1,500 RIN gal ons of advanced
biofuels.30
The 2020, 2021, and 2022 Proposed Rule
EPA released the proposed rule for the 2020, 2021, and 2022 RFS volume requirements on
December 7, 2021, and published the proposed rule in the Federal Register on December 21,
2021.31 EPA proposes to reduce the volume requirements from what is required by statute for
2020, 2021, and 2022 (see Table 1). More specifical y, EPA proposes to retroactively reduce the
previously finalized 2020 volume requirements for al fuel categories except biomass-based
diesel (a final rule was released for 2020),32 and to reduce the volume requirements for 2021 and
2022 to levels less than what is cal ed for in the statute (a final rule was not released for 2021 and
2022). EPA reports it is “proposing to reduce the applicable statutory volumes for 2020, 2021 and
2022 utilizing both the cel ulosic waiver and reset authorities.”33 EPA reports it is using different

26 42 U.S.C. §7547(o)(5)(D).
27 Although a gallon of a biofuel may be used to fulfill individual sub-requirements or the overall requirement, each
gallon counts once against the overall renewable fuel use obligation.
28 T he value of any biofuel within the RFS depends on the RIN price at a given time. As different categories of RINs
are used to meet the various standards, there is often a price difference between RINs (e.g., advanced biofuel RINs are
generally more expensive than conventional biofuel RINs). However, there is no public market for RINs, so real -time
price data are difficult to obtain. EPA does provide historical weekly RIN price data. Environmental Protection
Agency, RIN Trades and Price Inform ation, January 5, 2022.
29 40 C.F.R. §80.1415.
30 All EVs are in relation to the energy content of ethanol. T he EV for ethanol is 1.0. One gallon of biodiesel contains
roughly 1.5 times the energy of one gallon of ethanol, and thus h as an EV of 1.5.
31 U.S. Environmental Protection Agency, “ Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal
Register 72436, December 21, 2021.
32 U.S. Environmental Protection Agency, “Renewable Fuel Standard Program: Standards for 2020 and Biomass-Based
Diesel Volume for 2021 and Other Changes,” 85 Federal Register 7016, February 6, 2020.
33 U.S. Environmental Protection Agency, “ Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal
Congressional Research Service

5

The Renewable Fuel Standard (RFS): An Overview

waiver authorities for different years and different fuel categories.34 EPA reports that, for 2020
and 2021, it is proposing to set the volumes equal to the actual volumes of advanced biofuel and
total renewable fuel consumed during those years.35 EPA reports that, for 2022, it is proposing to
set volumes of advanced biofuel and total renewable fuel that “represent growth compared to
historical volumes and compared to the volumes proposed for 2020 and 2021.”36 EPA reports the
retroactive reduction of the 2020 volume requirements is necessary because “several significant
and unanticipated events” occurred fol owing the release of the 2020 final rule.37 These events
include the COVID-19 pandemic—which led to a drop in transportation fuel demand—and lower
than expected gasoline and diesel volume exemptions from the 2020 RFS obligations stemming
from smal refinery exemptions (SREs).38 Some Members of Congress have expressed interest in
the volumes for 2020 through 2022.39
EPA addresses other implementation duties in the proposed rule. For instance, EPA proposes to
address the court remand of the 2014-2016 final rule by adding a supplemental volume obligation
of 500 mil ion gal ons—250 mil ion gal ons each for 2022 and 2023.40 EPA reports that by
“applying the supplemental standard to 2022 instead of 2016, RINs generated in 2021 and 2022
could be used to comply with the 2022 supplemental standard” and that obligated parties “subject
to the 2022 standards would also be subject to the supplemental standard.”41 Additional y, EPA
resumes an effort it first proposed in 2016: to al ow the use of biointermediates to produce
qualifying renewable fuels under the RFS program.42 EPA reports it is re-proposing “many
aspects of the biointermediate provisions in the proposed [Renewables Enhancement and Growth

Register 72445, December 21, 2021. For more information on waiver authority for the RFS, see CRS Report R44045,
The Renewable Fuel Standard (RFS): Waiver Authority and Modification of Volum es, by Kelsi Bracmort .
34 Ibid. For example, EPA reports it is using solely the reset authority to set the total renewable fuel volume
requirement for 2021. EPA reports it is proposing to use both the cellulosic waiver authority and the rest authority to
set the total renewable fuel volume requirement for 2022.
35 For the 2021 volumes, EPA used actual consumption for months when such data were available and projected
consumption for the remaining months in the year. U.S. Environmental Protection Agency, “ Renewable Fuel Standard
(RFS) Program: RFS Annual Rules,” 86 Federal Register 72438-72439, 72445, 72448, and 72450, December 21, 2021.
36 U.S. Environmental Protection Agency, “ Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal
Register 72450, December 21, 2021.
37 U.S. Environmental Protection Agency, “ Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal
Register 72438, December 21, 2021.
38 For more information on small refinery exemptions, see CRS Report R46244, The Renewable Fuel Standard (RFS):
Frequently Asked Questions About Sm all Refinery Exem ptions (SREs) , by Kelsi Bracmort . T his report does not discuss
EPA’s proposal to deny over 60 petitions for small refinery exemptions. For more information , see U.S. Environmental
Protection Agency, Proposal to Deny Petitions for Sm all Refinery Exem ptions Proposal to Deny Petitions for Sm all
Refinery Exem ptions, EPA-420-D-21-001, December 7, 2021.
39 For example, legislation has been introduced that would prohibit the EPA Administrator from reducing the
renewable volume obligations once an annual rule is finalized ( S. 3380). Sen. Amy Klobuchar, “ Klobuchar, Grassley
Introduce Bipartisan Legislation to Provide Certainty to Biofuel Producers,” press release, December 14, 2021. In
contrast, some Members of Congress have requested that the EPA Administrator waive or significantly reduce the 2020
volume requirement, and set the 2021 and 2022 volume requirements at “ levels that comport with reality.” Letter from
Sen. Pat T oomey, Sen. Shelley Moore Capito, and Sen. Cynthia M. Lummis, et al. to Michael Regan, EPA
Administrator, August 23, 2021.
40 In short, the court decision requires EPA to address 500 million gallons of total renewable fuel that EPA reduced
from the 2016 mandate by improperly using the RFS general waiver authority. U.S. Environmental Protection Agency,
“Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal Register 72457, December 21, 2021.
41 U.S. Environmental Protection Agency, “ Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal
Register 72459, December 21, 2021.
42 U.S. Environmental Protection Agency, “Renewables Enhancement and Growth Support Rule,” 81 Federal Register
80833, November 16, 2016.
Congressional Research Service

6

The Renewable Fuel Standard (RFS): An Overview

Support (REGS)] rule but also updates several key aspects of that proposal reflecting what [the
agency has] learned since the original proposal.”43 In short, biointermediates are feedstocks made
from renewable biomass that are general y constructed into a more useable and easily
transportable form at one facility and converted to fuel at a different facility. EPA reports that
technologies that employ biointermediates could “provide an opportunity for the future growth in
production of the cel ulosic biofuels required under the RFS program.”44 Lastly, EPA is proposing
regulatory changes to include the treatment of confidential business information under the
program45 and defining “produced from renewable biomass,”46 among other actions.

43 U.S. Environmental Protection Agency, “ Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal
Register 72465, December 21, 2021.
44 U.S. Environmental Protection Agency, “ Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal
Register 72440, December 21, 2021.
45 U.S. Environmental Protection Agency, “ Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal
Register 72477, December 21, 2021.
46 U.S. Environmental Protection Agency, “ Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal
Register 72479, December 21, 2021.
Congressional Research Service

7

link to page 12 link to page 12 link to page 12 link to page 12 link to page 12 link to page 12 The Renewable Fuel Standard (RFS): An Overview

Table 1. Renewable Fuel Standard Statute, EPA Final and Proposed Volumes
(bil ions of gal ons)
Due Date
Cap on
and Actual
Convention
Date of
Portion from Advanced Biofuels
al Biofuel
Final Rule
Statute,
Total
Total
Biomass-
Final, or
Renewable
Advanced
Cellulosic
Based
Year
Proposed
Fuel
Biofuels
Biofuel
Diesel

2010
S
12.95
0.95
0.1000
0.65
12.00
Nov. 2009

F
12.95
0.95
0.0065
1.15
12.00
Feb. 2010
2011
S
13.95
1.35
0.2500
0.80
12.60
Nov. 2010

F
13.95
1.35
0.0060a
0.80
12.60
Nov. 2010
2012
S
15.20
2.00
0.5000
1.00
13.20
Nov. 2011

F
15.20
2.00
0.0105b
1.00
13.20
Dec. 2011
2013
S
16.55
2.75
1.0000
≥1.00
13.80
Nov. 2012

F
16.55
2.75
0.0008
1.28
13.80
Aug. 2013
2014
S
18.15
3.75
1.7500
≥1.00
14.40
Nov. 2013

F
16.28
2.67
0.0330
1.63
13.61
Nov. 2015
2015
S
20.50
5.50
3.0000
≥1.00
15.00
Nov. 2014

F
16.93c
2.88
0.1230
1.73
14.05
Nov. 2015
2016
S
22.25
7.25
4.2500
≥1.00
15.00
Nov. 2015

F
18.11c
3.61
0.2300
1.90
14.50
Nov. 2015
2017
S
24.00
9.00
5.5000
≥1.00
15.00
Nov. 2016

F
19.28
4.28
0.3110
2.00
15.00
Nov. 2016
2018
S
26.00
11.00
7.0000
≥1.00
15.00
Nov. 2017

F
19.29
4.29
0.2880
2.10
15.00
Nov. 2017
2019
S
28.00
13.00
8.5000
≥1.00
15.00
Nov. 2018

F
19.92
4.92
0.4180
2.10
15.00
Nov 2018
2020
S
30.00
15.00
10.5000
≥1.0
15.00
Nov. 2019

F / Pf
20.09 / 17.13
5.09 / 4.63
0.59 / 0.51
2.43
15.00 / 12.50
Dec 2019 /
Dec 2021
2021
S
33.00
18.00
13.5000
≥1.00
15.00
Nov. 2020

P
18.52
5.20
0.62
2.43d
13.32
Dec 2021
2022
S
36.00
21.00
16.0000
≥1.00
15.00
Nov. 2021

P
20.77
5.77
0.77
2.76
15.00
Dec 2021
(+ 0.25)g
2023
S
To Be Determined by the EPA Administratore
and
beyond
Congressional Research Service

8

link to page 11 The Renewable Fuel Standard (RFS): An Overview

Source: Energy Independence and Security Act of 2007 (EISA; P.L. 110-140); Final and proposed rules are
available at U.S. Environmental Protection Agency, Regulations and Volume Standards for Renewable Fuel Standards,
January 12, 2022, https://www.epa.gov/renewable-fuel-standard-program/regulations-and-volume-standards-
renewable-fuel-standards.
Notes: S = Statute, F = Final, P = Proposed, TBD = To Be Determined. Al volumes are ethanol equivalent,
except for biomass-based diesel, which is actual. The 2010 biomass-based diesel requirement of 1.15 bil ion
gal ons equals the 0.5 bil ion gal on requirement for 2009 plus the 0.65 bil ion gal on requirement for 2010. Cap
on Conventional Biofuel = Total Renewable Fuel – Total Advanced Biofuel. The total advanced biofuel
requirement equals the sum of cel ulosic biofuel and biomass-based diesel (both of which have annual volume
targets provided in statute and are identified in Table 1 in italics) plus other advanced biofuel (which does not
have an annual volume target provided in statute).
a. EPA rescinded the 2011 cel ulosic biofuel standard.
b. RFS Final Rule 2012, Federal Register, January 9, 2012. Subsequently vacated under American Petroleum
Institute v. EPA, D.C. Cir., No. 12-1139, 1/25/13.
c. The D.C. Circuit Court vacated EPA’s 2016 total renewable fuel volume requirement and remanded the
2015 final rule to EPA for reconsideration. Americans for Clean Energy v. EPA, No. 16 -1005, 2017 U.S. App.
LEXIS 13692, at *4-5 (D.C. Cir. July 28, 2017).
d. The 2021 final volume requirement for biomass-based diesel is 2.43 bil ion gal ons.
e. The EPA Administrator is to consult with the Secretaries of Energy and Agriculture and take into account
an analysis of certain factors to determine the volume amounts. 42 U.S.C. §754 5(o)(2)(B)(i ).
f.
Proposed retroactive modification of 2020 final volume requirements.
g. Supplemental standard of 250 mil ion gal ons proposed for 2022 to partial y address court remand of 2016
standard. EPA reports it intends to propose an additional supplemental volume of 250 mil ion gal ons for
2023 in a subsequent action. U.S. Environmental Protection Agency, “Renewable Fuel Standard (RFS)
Program: RFS Annual Rules,” 86 Federal Register 72457, December 21, 2021.
RFS Implementation Issues
Implementation of the RFS has been complex, and compliance with some of its parts has been
chal enging, according to some stakeholders. This section briefly explains some of the general
concerns and chal enges with implementing the RFS.
Administering Agency
EPA administers the RFS.47 This responsibility includes evaluating renewable fuel pathways
eligible for the RFS.48 In addition, EPA is required to evaluate the ability of the biofuel industry to
produce enough fuel to meet the annual volume standard, release an annual volume standard
based on its research findings,49 and ensure that annual compliance by obligated parties is met.

47 Although the RFS is administered by EPA, programs under other federal departments may indirectly assist biofue l
production that may be used to meet the mandate. For example, the U.S. Department of Agriculture (USDA) provides
resources and support for biofuel feedstock development and supply, biofuel infrastructure development, advanced
biofuel production, and more (e.g., Rural Energy for America Program, Advanced Biofuel Payment Program, and
Higher Blends Infrastructure Investment Program). For more information on energy programs administered by USDA,
see CRS Report R45943, The Farm Bill Energy Title: An Overview and Funding History, by Kelsi Bracmort .
48 A fuel pathway consists of three components: a biomass feedstock, a biofuel production process, and a fuel type
(e.g., ethanol made from corn starch using a dry mill production process). T he fuel pathway is assigned to a renewable
fuel category (known by its D code provided in T able 1 of 40 C.F.R. §80.1426 in the RFS regulations) which signifies
which RIN the biofuel is eligible for to be in compliance with the RFS. EPA maintains a list of approved fuel pathway
and fuel pathway petitions on its website (https://www.epa.gov/renewable-fuel-standard-program/approved-pathways-
renewable-fuel).
49 Frequently, EPA has approved annual standards for some biofuels different from what was originally scheduled in
statute.
Congressional Research Service

9

The Renewable Fuel Standard (RFS): An Overview

Al of the above must be completed annual y, taking into consideration comments from other
government agencies and the public and directives from court decisions. These responsibilities
could be viewed as an addition to EPA’s regulatory workload and have required EPA to develop
new capabilities to carry them out.
In the years following the 2010 issuance of the amended RFS final rule,50 EPA has used its waiver
authorities to set annual volume requirements for cel ulosic biofuel, total advanced biofuel, and
total renewable fuel below the amounts stated in the statute.51 Legal chal enges have been brought
against the EPA regarding some of these annual fuel volume requirements and the projections on
which they were based. For instance, the American Petroleum Institute objected to EPA’s 2012
cel ulosic biofuel production projection methodology, among other things, and chal enged it in
court. The federal court vacated the 2012 cel ulosic biofuel standard and provided principles for
EPA to apply to future annual projections.52 Likewise, Americans for Clean Energy and other
petitioners chal enged various aspects of the final rule that set the volume requirements and
projections for 2014-2016 and 2017 for biomass-based diesel, including EPA’s interpretation of
“inadequate domestic supply” in exercising its general waiver authority to reduce the total
volume requirements. The D.C. Circuit held that EPA’s interpretation of “inadequate domestic
supply” was not reasonable and that EPA had improperly exercised its waiver authority as a
result. It vacated EPA’s 2016 total renewable fuel volume requirement and remanded the final
rule to EPA for reconsideration consistent with the court’s decision.53
In some instances, the timing of EPA’s RFS regulatory actions, such as the annual announcement
of the renewable fuel volume requirements, has not met statutory deadlines. The more recent final
rules general y adhere to the statutory schedule.54 However, some of the earlier final rules did not
meet the statutory deadline.55 A lack of timely rulemaking combined with inaccurate volume
projections could affect private investment, according to some advanced biofuel producers.56
Additional y, the amount of time it takes the agency to approve new fuel pathways and register
new facilities has been raised in public comments to proposed RFS rules.57 Slow approval could
potential y stifle investment and production of new fuels. Further, prolonged processing time for
some program enhancement rules—such as the proposed Renewables Enhancement and Growth
Support rule (REGS rule)—may impede the growth of the program.58

50 EPA, “Regulation of Fuels and Fuel Additives: Changes to Renewable Fuel Standard Program; Final Rule,” 75
Federal Register 14670, March 26, 2010.
51 For more discussion, see CRS Report R44045, The Renewable Fuel Standard (RFS): Waiver Authority and
Modification of Volum es, by Kelsi Bracmort .
52 American Petroleum Institute v. EPA, 706 F.3d 474 (D.C. Cir. 2013). More discussion of this legal challenge is in
CRS Report R41106, The Renewable Fuel Standard (RFS): Cellulosic Biofuels, by Kelsi Bracmort.
53 Americans for Clean Energy v. EPA, 864 F.3d 691, 737 (D.C. Cir. 2017).
54 Under the Clean Air Act, each year’s standards are required to be announced by November 30 of the previous year.
55 EPA’s late announcement of the annual requirements may be due to the depth of the analysis (e.g., difficulty in
obtaining reliable and timely information from the industry) or to other factors.
56 Written statement by Nebraska Governor Pete Ricketts, Chairman, Governors’ Biofuels Coalition, U.S. Environment
Protection Agency, Public Hearing, Proposed Renewable Fuel Standard Program : Standards for 2018 and Biom ass -
Based Diesel Volum e for 2019, Washington, DC, August 1, 2017.
57 EPA, Renewable Fuel Standard Program —Standards for 2020 and Biomass-Based Volume for 2021: Response to
Com m ents, EPA-420-R-19-018, December 2019.
58 EPA issued the proposed REGS rule in November 2016. T he REGS rule would modify RFS program regulations to
increase production of cellulosic and other advanced biofuels, among other things. EPA requeste d comment on
multiple provisions of the proposed REGS rule in the 2020 RFS proposed rule and finalized some of those provisions
in the 2020 final rule. It is not clear when EPA will act on those provisions not finalized in the 2020 final rule.
Congressional Research Service

10

The Renewable Fuel Standard (RFS): An Overview

Lastly, EPA has the authority to “reset” the RFS. The “reset” authority al ows the EPA
Administrator to adjust the applicable volumes of the RFS for future years starting in 2016 if
certain conditions are met.59 EPA reports in the proposed rule to set 2020, 2021, and 2022
volumes that the “reset” provision for the RFS has been triggered for three of the four renewable
fuel categories identified in statute.60 EPA reports the “conditions for resetting cel ulosic biofuel
volumes were met by the 2010 annual standard, which reduced the applicable cel ulosic biofuel
volume by at least 50 percent.”61 EPA reports the “conditions for resetting advanced biofuel
volumes were met by the 2014 and 2015 annual standards, which reduced the applicable
advanced biofuel volume by at least 20 percent for two consecutive years.”62 And, EPA reports
the “conditions for resetting total renewable fuel volumes were met by the 2018 and 2019 annual
standards, which reduced the applicable total renewable fuel volume by at least 20 percent for
two consecutive years.”63 How EPA implements this provision likely wil affect renewable fuel
production and compliance with the overal program.64
Qualifying Biofuels
As noted above, there are a number of nested categories within the RFS; a fuel may qualify as a
biofuel for one or more portions of the mandate.65 Difficulty by some advanced biofuel producers
in understanding which advanced biofuels qualify for the RFS can lead to chal enges in
determining how compliance is being met.66
Not al fuels from a renewable source are eligible under the RFS. The RFS operates as a biofuel
standard, with priority assigned to liquid transportation fuels from biomass feedstocks.67 Other
renewable sources (e.g., wind) do not qualify. Before a fuel can generate RFS RINs, however,
that fuel pathway must be approved by EPA; according to advanced biofuel producers, that

Additionally, in the 2020, 2021, and 2022 proposed rule, EPA is requesting comment on the use of biointermediates
which was also discussed in the REGS rule. U.S. Environmental Protection Agency, “Renewables Enhancement and
Growth Support Rule: Proposed Rule,” 81 Federal Register 80828, November 16, 2016; U.S. Environmental
Protection Agency, “Renewable Fuel Standard Program: Standards for 2020 and Biomass-Based Diesel Volume for
2021 and Other Changes,” 85 Federal Register 7016, February 6, 2020; U.S. Environmental Protection Agency,
“Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal Register 72465, December 21, 2021.
59 For more discussion of the reset provision, see CRS Report R44045, The Renewable Fuel Standard (RFS): Waiver
Authority and Modification of Volum es, by Kelsi Bracmort .
60 U.S. Environmental Protection Agency, “ Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal
Register 72442, December 21, 2021.
61 Ibid.
62 Ibid.
63 Ibid.
64 In the 2020, 2021, and 2022 proposed rule, EPA proposes to use both the cellulosic waiver authority and the reset
authority to set the 2020, 2021, and 2022 volume requirements.
65 Approved RFS fuels and feedstocks are provided by EPA at https://www.epa.gov/renewable-fuel-standard-program/
approved-pathways-renewable-fuel.
66 For example, there were questions by some about the eligibility of algae-based biofuels for the RFS. For more
information, see CRS Report R42122, Algae’s Potential as a Transportation Biofuel, by Kelsi Bracmort .
67 In July 2014, EPA approved new cellulosic and advanced biofuel pathways to include the production of compressed
natural gas, liquefied natural gas, and electricity from biogas from landfills, municipal waste -water treatment facility
digesters, agricultural digesters, and separated municipal solid waste digesters. Co mpliant fuels for the RFS also
include heating oil and jet fuel. See EPA, “ Regulation of Fuels and Fuel Additives: RFS Pathways II, and T echnical
Amendments to the RFS Standards and E15 Misfueling Mitigation Requirements; Final Rule,” 79 Federal Register
138, July 18, 2014. EPA, “ Regulation of Fuels and Fuel Additives: Modifications to Renewable Fuel Standard Program
– Final Rule,” 78 Federal Register 62462, October 22, 2013.
Congressional Research Service

11

The Renewable Fuel Standard (RFS): An Overview

process can take a considerable amount of time for some fuels.68 EPA reports it has approved over
100 facility-specific pathway petitions since 2010.69 As of January 2022, EPA reports there are 23
pending pathway petitions.70
Lastly, some may view the RFS as a biofuel production mandate. The statutory language does not
mandate the production of biofuels; rather, it mandates the use of biofuel. However, it could be
argued that it is difficult to use a fuel that is not being produced and that the RFS therefore
indirectly creates a demand for certain biofuels and thus stimulates their production.
Cellulosic Biofuel Production
By statute, cel ulosic biofuel is targeted to comprise approximately 44% of the total renewable
fuel mandate in 2022. However, the annual cel ulosic biofuel volume target established by
Congress is not being met. Actual cel ulosic biofuel production volumes (e.g., cel ulosic ethanol)
are below the expectations set when the law was passed. The statute contains a cel ulosic biofuel
waiver authority that, in short, al ows the EPA Administrator to reduce the cel ulosic biofuel
mandate when the projected production capacity for a given year is less than the volume required
in the statute.71 For instance, in 2020, the statute requires 10.5 bil ion gal ons of cel ulosic biofuel.
EPA set the 2020 target volume at 590 mil ion gal ons for 2020, and, in its latest proposed rule,
EPA proposes to retroactively set the cel ulosic biofuel requirement at 510 mil ion gal ons. This
gap is due to several factors, including lack of private investment, logistical chal enges,
technology setbacks, and uneven support from the federal government.72 These factors, coupled
with the fact that annual volumes in the statute were established w hen market conditions for
raising investment capital for new biofuel technologies were more favorable, may suggest
unrealistic targets for some advanced biofuels. These production limitations have raised questions
about whether the statutory cel ulosic biofuel volumes are attainable.
Blend Wall
The “blend wal ” is a term used to describe the upper limit to the total amount of ethanol that can
be blended into U.S. gasoline and stil maintain automobile performance and comply with other
provisions of the Clean Air Act. The blend wal has been viewed by many to be in direct conflict
with the biofuel volumes mandated in the RFS.73 Thus far, the largest volume being met under the
RFS is for the implied conventional biofuel segment of the mandate, met mainly with corn starch
ethanol blended into gasoline. Due to a variety of factors (e.g., automaker warranty coverage,
fueling station infrastructure, etc.), ethanol content in gasoline is general y limited to 10% (E10).

68 Biotechnology Innovation Organization, “2018 RFS Volumes Set Back Growth in Cellulosic Biofuels,” press
release, November 30, 2017, https://www.bio.org/press-release/2018-rfs-volumes-set-back-growth-cellulosic-biofuels;
“BIO Encourages EPA to Speed Approvals of New Biofuel Pathways,” Business Wire, March 31, 2014,
https://www.businesswire.com/news/home/20140331006205/en/BIO-Encourages-EPA-Speed-Approvals-New-Biofuel.
69 U.S. Environmental Protection Agency, “Renewable Fuel Standard Program: Standards for 2020 and Biomass-Based
Diesel Volume for 2021 and Other Changes,” 85 Federal Register 7057, February 6, 2020.
70 U.S. Environmental Protection Agency, Pending Petitions for Renewable Fuel Pathways, January 5, 2022,
https://www.epa.gov/renewable-fuel-standard-program/pending-petitions-renewable-fuel-pathways.
71 42 U.S.C. 7545(0)(7)(D).
72 For more discussion, see CRS Report R41106, The Renewable Fuel Standard (RFS): Cellulosic Biofuels, by Kelsi
Bracmort .
73 For more discussion, see CRS Report R40445, Intermediate-Level Blends of Ethanol in Gasoline, and the Ethanol
“Blend Wall”, by Kelsi Bracmort.
Congressional Research Service

12

The Renewable Fuel Standard (RFS): An Overview

With a relatively fixed supply of gasoline, the amount of ethanol that can be supplied this way is
also limited.
In the past, under economic conditions at that time (i.e., 2018 and 2019), the blend wal was a
concern to some, but it may not have been as significant an impediment to immediate fuel
consumption as previously considered.74 In December 2019, EPA reported “the E10 blend wal is
not the barrier that some commenters believe it to be.”75 However, a significant reduction in
gasoline consumption would likely require a reduction in the amount of ethanol needed to be
blended into the gasoline. More recently, the U.S. Energy Information Administration (EIA)
reports that 2020 U.S. motor gasoline consumption decreased to its lowest level since 1997,
mainly due to responses to the COVID-19 pandemic.76 EIA also reports that ethanol production
changes followed motor gasoline production changes—particularly at the beginning of the
COVID-19 pandemic.77 EPA proposes to respond to these 2020 decreases, in part, by
retroactively adjusting “the 2020 volumes and standards to reflect the actual volumes of
renewable fuels and transportation fuel consumed in the U.S.”78 It is not clear how long the
COVID-19 pandemic wil last and how the pandemic may affect future motor gasoline
consumption. Thus, it is difficult to determine what future impacts COVID-19 could potential y
have on the blend wal and RFS compliance, among other things.
There are some possible approaches that could al eviate blend wal concerns. One option is to
blend higher levels of ethanol into conventional gasoline. In 2011, EPA granted a Clean Air Act
waiver that al ows gasoline to contain up to 15% ethanol for use in model year 2001 and newer
light-duty motor vehicles.79 However, limited demand, legal constraints limiting E15 sales to
winter months, and infrastructure and automobile warranty concerns have precluded widespread
offering and purchase of E15. Nonetheless, widespread use of E15 could potential y postpone the
blend wal for some time.
Another option to address the blend wal would be increasing the use of ethanol in flexible-fuel
vehicles capable of using E85, a gasoline-ethanol blend containing 51% to 83% ethanol.80

74 Sen. James M. Inhofe, “Inhofe, Senators Urge RFS Policy to Reflect Market Realities,” press release, May 1, 2019;
Renewable Fuels Association, “DOE Data Show 31 States Broke T hrough So-Called ‘Blend Wall’ in 2016,” press
release, February 2, 2018, https://ethanolrfa.org/2018/02/doe-data-show-31-states-broke-called-blend-wall-2016/.
75 EPA, Renewable Fuel Standard Program —Standards for 2020 and Biomass-Based Volume for 2021: Response to
Com m ents, EPA-420-R-19-018, December 2019.
76 U.S. Energy Information Administration, U.S. Petroleum Consumption Decreased to a 25-Year Low in 2020, August
5, 2021. U.S. Energy Information Administration (EIA) data for motor gasoline supply shows a steep decline in late
March 2020. U.S. Energy Information Administration, Weekly U.S. Product Supplied of Finished Motor Gasoline,
January, 10, 2022, https://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=WGFUPUS2&f=W.
77 U.S. Energy Information Administration, U.S. Fuel Ethanol Production and Inventory Changes Have Largely
Followed Motor Gasoline, June 8, 2020.
78 U.S. Environmental Protection Agency, “ Renewable Fuel Standard (RFS) Program: RFS Annual Rules,” 86 Federal
Register 72438, December 21, 2021.
79 For more information, see U.S. Environmental Protection Agency, Ethanol Waivers (E15 and E10), April 1, 2020,
https://www.epa.gov/gasoline-standards/ethanol-waivers-e15-and-e10. In 2019, EPA issued a final rule allowing year-
round E15 sales. For more discussion, see CRS Insight IN10979, Year-Round Sale of E15, by Kelsi Bracmort . In 2021,
the rule was vacated by the U.S. Court of Appeals for the District of Columbia Circuit. Am erican Fuel &
Petrochem ical Manufacturers v. Environm ental Protection Agency, USCA Case #19-1124 (United States Court of
Appeals for the District of Columbia Circuit 2021).
80 T he U.S. Department of Energy (DOE) reports that as of 2018 there were more than 21 million FFV in the United
States. U.S. Department of Energy Alternative Fuels Data Center, Flexible Fuel Vehicles, January 10, 2022. T he U.S.
Department of T ransportation reports there were 250.7 million light -duty vehicles in the United States in 2018. U.S.
Department of T ransportation Bureau of T ransportation Statistics, Num ber of U.S. Aircraft, Vehicles, Vessels, and
Congressional Research Service

13

The Renewable Fuel Standard (RFS): An Overview

However, there are infrastructure constraints with the use of E85. For example, the number of
E85 fueling stations is limited.81 There are government infrastructure initiatives aimed at
increasing the availability of E15 and other higher ethanol-gasoline blends. For example, the U.S.
Department of Agriculture (USDA) administers the Higher Blends Infrastructure Incentive
Program (HBIIP), with an overal goal to increase the sales and use of higher blends of ethanol
and biodiesel.82 USDA reports the program wil do this, in part, by “sharing the costs related to
and/or offering sales incentives for the instal ation of fuel pumps, related equipment, and
infrastructure.”83
Other Factors
The RFS is not a stand-alone program. The implementation and impacts of the program are
affected by many factors that are not easily predicted or controlled. For example, cel ulosic
biofuel production, at a minimum, requires conversion technology, which itself requires technical
expertise and time to ramp up to commercial scale. The large quantity of biomass feedstocks
needed to produce such biofuels requires factors such as appropriate weather conditions and an
expectation of stable markets for feedstock commodities. Further, some types of biofuel
production thus far have been sensitive to the availability of tax incentives in order to be
economical y feasible (e.g., biodiesel).84 Unexpected occurrences (e.g., drought, failed
technology, tax incentive expiration, trade disputes) could potential y impact an entire industry,
especial y for some advanced biofuels in nascent industries compared to conventional
transportation fuels.
Congressional Issues
The RFS was established in 2005 at a time when Congress foresaw the need to diversify the
country’s energy portfolio, strengthen the economy of rural communities that could contribute to
biofuel production, bolster U.S. standing in an emerging segment of the energy technology
market, and protect the environment, among other objectives. The RFS was subsequently
expanded in 2007. Since then, some components of the RFS (e.g., corn starch ethanol, biomass-
based diesel) have progressed steadily toward meeting statutory requirements and other
components (e.g., cel ulosic biofuel) have not.
There has been perennial legislative interest, executive activity, and litigation regarding the RFS.
Several factors have led to congressional interest in the RFS—including the statutory
requirements, the implementation process, stakeholder interests, complementary programs,
actions of federal agencies, and agricultural trade issues, among other things. Further, the RFS is
a program with elements and objectives that are interpreted differently by the parties that must
abide by the underlying statute.

Other Conveyances, January 10, 2022.
81 T he U.S. Department of Energy reports there were 4,121 E85 fueling stations as of January 2022. U.S. Department
of Energy, Ethanol Fueling Station Locations, January 10, 2022, https://afdc.energy.gov/fuels/ethanol_locations.html#/
analyze?fuel=E85.
82 For more information about HBIIP, see the HBIIP website at https://www.rd.usda.gov/hbiip.
83 U.S. Department of Agriculture, “Announcement of Future Competitive Grant Funds Availability f or Higher Blends
Infrastructure Incentive Program (HBIIP) for Fiscal Year 2020,” 85 Federal Register 11946, February 28, 2020.
84 For example, see U.S. Energy Information Administration, U.S. Biomass-Based Diesel Tax Credit Renewed Through
2022 in Governm ent Spending Bill, January 28, 2020.
Congressional Research Service

14

The Renewable Fuel Standard (RFS): An Overview

Congress may consider the following RFS items (in no particular order) as it continues to debate
the merits and chal enges of the RFS:
 Timing. 2022 is the last year that the RFS program has annual volumes
contained in statute. After 2022, the EPA Administrator determines the annual
volume amounts.
 Reset. The EPA Administrator has the authority to modify the volume
requirements for future years for the total renewable fuel, advanced biofuel, and
cel ulosic biofuel categories if certain statutory criteria are met. (EPA has
proposed using this authority for 2020 through 2022.)
 Fuel pathways. Fuel pathways must be approved by EPA in order for a fuel to be
eligible for the RFS. The time it takes and the resources EPA has to approve the
pathways are unclear.
 Volume targets. The statutory targets have not been met for the last several years
for three of the four fuel categories: renewable fuel, advanced biofuel, and
cel ulosic biofuel. The statutory target for biomass-based diesel has been met as
has the implied target for conventional biofuel.
 Environmental impact. EPA is to provide Congress with a report every three
years that assesses the impact of the RFS on environmental issues and resource
conservation issues, among other things.85 There are various perspectives about
the environmental impact of the RFS.86
 RFS compliance. A tradeable credit system is used to ensure obligated parties
comply with the RFS. At times, the availability and cost of the credits (i.e., RINs)
and the transparency of the market have been a concern to some.87
 Small refinery exemptions. Smal refineries may petition the EPA Administrator
for an exemption from the RFS mandate if they can prove compliance would
subject them to disproportionate economic hardship.88 Some Members of
Congress question how EPA evaluates the petitions and how EPA accounts for
such exemptions, among other things.

85 In 2021, EPA reported that “[t]he T hird T riennial Report to Congress is under development and scheduled to be
provided to Congress in 2021.” U.S. Environmental Protection Agency, Energy and the Environment Research,
January 10, 2022, https://www.epa.gov/air-research/energy-and-environment-research. EISA Section 204. U.S.
Environmental Protection Agency, Biofuels and the Environm ent: The Second Triennial Report to Congress,
EPA/600/R-18/195, June 29, 2018. U.S. Environmental Protection Agency, Biofuels and the Environm ent: First
Triennial Report to Congress, EPA/600/R-10/183F, December 2011.
86 U.S. Government Accountability Office, Renewable Fuel Standard: Information on Likely Program Effects on
Gasoline Prices and Greenhouse Gas Em issions, GAO-19-47, May 2019; Clean Air T ask Force, EPA’s Report on the
Environm ental Im pacts of Biofuels, July 9, 2018; Biotechnology Innovation Organization, New Study: Biofuel Use
Saved 589.3 Million Tons of Carbon Em issions over the Past Decade, August 24, 2015.
87 For more information, see U.S. Congress, House Committee on Energy and Commerce, Subcommittee on
Environment, Background on Renewable Identification Num bers under the Renewable Fuel Standard , T estimony of
Brent Yacobucci, 115th Cong., July 25, 2018.
88 For more information on small refinery exemptions, see CRS Report R46244, The Renewable Fuel Standard (RFS):
Frequently Asked Questions About Sm all Refinery Exem ptions (SREs) , by Kelsi Bracmort .
Congressional Research Service

15

The Renewable Fuel Standard (RFS): An Overview

Author Information

Kelsi Bracmort

Specialist in Natural Resources and Energy Policy

Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan
shared staff to congressional committees and Members of Congress. It operates solely at the behest of and
under the direction of Congress. Information in a CRS Report should n ot be relied upon for purposes other
than public understanding of information that has been provided by CRS to Members of Congress in
connection with CRS’s institutional role. CRS Reports, as a work of the United States Government, are not
subject to copyright protection in the United States. Any CRS Report may be reproduced and distributed in
its entirety without permission from CRS. However, as a CRS Report may include copyrighted images or
material from a third party, you may need to obtain the permission of the copyright holder if you wish to
copy or otherwise use copyrighted material.

Congressional Research Service
R43325 · VERSION 44 · UPDATED
16