n-26-53.pdf

Preserve advance releases and the authoritative Internal Revenue Bulletin rendition; directory timestamps are file-publication metadata, not legal effective dates. HTML bulletins begin June 2003; earlier available issues require full PDF parsing.

This collection currently includes the publisher’s available advance-release directory. Historical bulletin renditions are discovered separately; an advance-release record alone does not certify the collection archive complete.

- 1 -

Part III - Administrative, Procedural, and Miscellaneous

Section 45Z Clean Fuel Production Credit; Emissions Rates

Notice 2026-53

SECTION 1. PURPOSE
This notice provides guidance on the establishment of emissions rates under
§ 45Z(b)(1)(B) of the Internal Revenue Code (Code)
1
for the clean fuel production credit
determined under § 45Z (§ 45Z credit) and clarifies the application of certain
amendments to § 45Z made by § 70521 of Public Law 119-21, 139 Stat. 72, 276 (July
4, 2025), commonly known as the One, Big, Beautiful Bill Act (OBBBA). Specifically,
this notice addresses the establishment of emissions rates for transportation fuel
derived from animal manure. This notice also describes how certain regenerative
agricultural feedstock practices may be taken into account for purposes of § 45Z. The
Appendix to this notice provides the annual emissions rate table for calendar year 2026
for purposes of § 45Z.
The Department of the Treasury (Treasury Department) and the Internal
Revenue Service (IRS) developed this notice in consultation with the Department of

1
Unless otherwise specified, all references to “section” or “§” are references to sections of the Code or
the Income Tax Regulations (26 CFR part 1).

- 2 -
Energy (DOE), the United States Department of Agriculture (USDA), the Federal
Aviation Administration (FAA), and other federal agencies.
SECTION 2. BACKGROUND
.01 In general.

Section 45Z, as amended by § 70521 of the OBBBA, provides an income tax
credit for clean transportation fuel produced domestically after December 31, 2024, and
sold by December 31, 2029. Among other requirements to qualify for the § 45Z credit, a
taxpayer must produce a “transportation fuel” that meets certain suitability, emissions
rate, anti-coprocessing, and anti-double-crediting requirements. See § 45Z(a)(1) and
(d)(5)(A). Under § 45Z(d)(5)(A)(ii), the emissions rate requirement is met if a
transportation fuel has an emissions rate
2
that is not greater than a statutory baseline of
50 kilograms (kg) of carbon dioxide equivalent based on relative global warming
potential (CO
2
e) per million British thermal units (mmBTU).
A taxpayer calculates the amount of the § 45Z credit by multiplying the applicable
amount per gallon or gallon equivalent with respect to a transportation fuel produced by
the taxpayer and sold in a qualified sale by the emissions factor for such fuel. See
§ 45Z(a)(1). Per § 45Z(a)(5), the credit amount is rounded to the nearest cent. A
taxpayer’s total § 45Z credit for a taxable year is the sum of the § 45Z credit for each
transportation fuel sold during the taxable year.
.02 Establishment of emissions rates.

Under § 45Z(b)(1)(A), a transportation fuel’s emissions factor measures the

2
Section 45Z(b)(1)(B)(i) provides that a transportation fuel’s emissions rate is based on the amount of
lifecycle greenhouse gas (GHG) emissions (as described in § 211(o)(1)(H) of the Clean Air Act (42 U.S.C.
7545(o)(1)(H)), as in effect on August 16, 2022) for such fuel, expressed as kg of CO
2
e per mmBTU. See
also § 45Z(d)(1)–(3).

- 3 -
reduction in the fuel’s emissions rate relative to the statutory baseline emissions rate of
50 kg of CO
2
e per mmBTU, expressed as a fraction of the statutory baseline. Under
§ 45Z(b)(2), any emissions factor must be rounded to the nearest multiple of 0.1.
Generally, a taxpayer must determine a transportation fuel’s emissions rate by
using the annual emissions rate table published by the Secretary of the Treasury or the
Secretary’s delegate (Secretary). See § 45Z(b)(1)(B). However, a taxpayer producing
a transportation fuel for which an emissions rate has not been established in the annual
emissions rate table may file a petition with the Secretary for determination of a
provisional emissions rate (PER) with respect to such fuel. See § 45Z(b)(1)(D).
Section 45Z(b)(1)(B)(i) directs the Secretary, subject to § 45Z(b)(1)(B)(ii) through
(v), to annually publish a table setting forth the emissions rates for similar types and
categories of transportation fuels. Section 2.03 of this notice describes
§ 45Z(b)(1)(B)(iv) and (v), added by the OBBBA. The Appendix to this notice provides
the calendar year 2026 emissions rate table.
Section 45Z(b)(1)(B)(ii) provides that for transportation fuel other than
sustainable aviation fuel (non-SAF transportation fuel), the lifecycle GHG emissions of
such fuel must be based on the most recent determinations under the Greenhouse
gases, Regulated Emissions, and Energy use in Transportation (GREET) model
developed by Argonne National Laboratory, or a successor model as determined by the
Secretary. See section 2.04(3) of this notice.
Section 45Z(b)(1)(B)(iii) provides that for transportation fuel that is sustainable
aviation fuel (SAF transportation fuel), the lifecycle GHG emissions of such fuel must be
determined in accordance with: (i) the most recent Carbon Offsetting and Reduction

- 4 -
Scheme for International Aviation (CORSIA) methodologies that have been adopted by
the International Civil Aviation Organization with the agreement of the United States; or
(ii) any methodology similar to the most recent CORSIA methodologies that satisfies the
criteria under § 211(o)(1)(H) of the Clean Air Act, as in effect on August 16, 2022.
Section 2.04(3) of this notice discusses the use of the 45ZCF-GREET model
pursuant to § 45Z(b)(1)(B)(ii) and (iii). All publicly available versions of the 45ZCF-
GREET model, the accompanying user manual, additional information including FAQs,
and the log of changes to the model are available at https://www.energy.gov/cmei/greet.
.03 OBBBA amendments.

Section 70521 of the OBBBA made several amendments to § 45Z affecting the
establishment of emissions rates and credit eligibility that apply only to transportation
fuel produced after December 31, 2025. Transportation fuel produced before
January 1, 2026, even if sold after December 31, 2025, is not subject to these
amendments. These statutory amendments include:
(1) The requirement in § 45Z(b)(1)(B)(iv) that the emissions rate of transportation
fuel produced after December 31, 2025, must be adjusted, based on regulations or
methodologies determined by the Secretary, to exclude any emissions attributed to
indirect land use change (ILUC).
(2) The requirement in § 45Z(b)(1)(B)(v)(I) for the Secretary to provide a distinct
emissions rate with respect to any transportation fuel derived from animal manure and
produced after December 31, 2025, that is based on the specific animal manure
feedstock. Such feedstocks may include dairy manure, swine manure, poultry manure,
or any other sources as are determined appropriate by the Secretary. See

- 5 -
§ 45Z(b)(1)(B)(v)(I).
(3) The requirement in § 45Z(b)(1)(B)(v)(II) and (b)(1)(E) that the emissions rate
cannot be less than zero for any transportation fuel produced after December 31, 2025,
except for any transportation fuel derived from animal manure.
(4) The requirement in § 45Z(f)(1)(A)(iii) that transportation fuel produced after
December 31, 2025, must be exclusively derived from a feedstock that was produced or
grown in the United States, Mexico, or Canada.
Section 4 of this notice clarifies how a taxpayer using an allowed methodology
that does not reflect these amendments should apply those amendments to determine
the emissions rate of transportation fuel produced after December 31, 2025. See
generally section 2.04 of this notice.
.04 Current guidance on emissions rates.

(1) In general.
On February 4, 2026, the Treasury Department and the IRS published proposed
regulations under § 45Z (REG-121244-23) in the Federal Register at 91 F.R. 5160
(§ 45Z NPRM), which provide guidance for determining the § 45Z credit, including the
establishment of emissions rates for transportation fuels under proposed § 1.45Z-2(d).
3

Proposed § 1.45Z-2(d)(1) would implement the general rules for determining the
emissions rate of a transportation fuel in § 45Z(b)(1)(B) and (D): a taxpayer would either
use the applicable emissions rate table published by the Secretary or, if the applicable
emissions rate table does not establish an emissions rate for the taxpayer’s fuel, a PER
determined by the Secretary.

3
Terms used in this notice have the same meaning as provided in § 45Z and the § 45Z NPRM.

- 6 -
Proposed § 1.45Z-2(e) would incorporate the rules in § 45Z(b)(1)(B) regarding
the annual publication of a table of emissions rates for similar types and categories of
transportation fuels, including the requirement in § 45Z(b)(1)(B)(i) that the emissions
rate table be published “[s]ubject to” the requirements in § 45Z(b)(1)(B)(ii) through (v).
Proposed § 1.45Z-2(g) would provide that when an emissions rate is first
established for a type and category of fuel, whether in an applicable emissions rate
table or by a PER determination, that emissions rate will relate back to January 1, 2025.
(2) Applicable emissions rate table.
Proposed § 1.45Z-2(e)(2) would provide rules for identifying the “applicable
emissions rate table” that a taxpayer must use in a given taxable year. Proposed
§ 1.45Z-2(e)(2)(i) would clarify that the applicable emissions rate table for a taxpayer is
the emissions rate table that is in effect on the first day of the taxpayer’s taxable year of
production.
Proposed § 1.45Z-2(e)(2)(ii) would clarify that if a taxpayer produces a fuel for
which the applicable emissions rate table establishes an emissions rate, the taxpayer
must use the corresponding allowed methodologies, as specified in proposed § 1.45Z-
2(e)(3), as provided in such table to determine the emissions rate for all such fuel
produced during the taxpayer’s taxable year.
Proposed § 1.45Z-2(e)(2)(iii)(A) would clarify that the applicable emissions rate
table establishes the emissions rate for a fuel if the emissions rate table includes both
the “type of transportation fuel” and “category of transportation fuel” (that is, the fuel’s
unique primary feedstock and pathway used to produce a type of transportation fuel), as
defined in proposed § 1.45Z-1(b)(35). Proposed § 1.45Z-2(e)(2)(iii)(B) would clarify that

- 7 -
if an emissions rate table does not initially include a type or category of fuel, but an
allowed methodology is updated to add such type or category of fuel during the
calendar year, then that type or category of fuel is considered included in such
emissions rate table.
(3) Allowed methodologies.
Proposed § 1.45Z-2(e)(3)(i) would provide that a taxpayer producing a fuel for
which an emissions rate is established by the applicable emissions rate table must
determine the fuel’s emissions rate using the allowed methodologies described in
proposed § 1.45Z-2(e)(3)(iv) and (v), as directed by the applicable emissions rate table.
Proposed § 1.45Z-2(e)(3)(ii) would require a taxpayer to use the first version of
an allowed methodology that is publicly available in the taxable year of production and
that includes the type and category of the taxpayer’s fuel. However, if an updated
version of an allowed methodology becomes publicly available after the first day of the
taxable year of production (but still within such taxable year), then the taxpayer could
choose to treat such updated version as the most recent version of such methodology.
The preamble to the § 45Z NPRM discusses how the phrase “most recent
determinations under the Greenhouse gases, Regulated Emissions, and Energy use in
Transportation model” in § 45Z(b)(1)(B)(ii) is best understood as referring to the most
recent determinations under the 45ZCF-GREET model. To address any potential
uncertainty given the continued existence of other GREET models, proposed § 1.45Z-
2(e)(3)(iii) would designate the 45ZCF-GREET model as a successor model under
§ 45Z(b)(1)(B)(ii). Proposed § 1.45Z-2(e)(3)(v) would clarify that the SAF portion of the
45ZCF-GREET model is a “similar methodology” to CORSIA under

- 8 -
§ 45Z(b)(1)(B)(iii)(II).
Proposed § 1.45Z-2(e)(3)(iv) and (v) would identify the allowed methodologies for
determining emissions rates for purposes of the emissions rate table described in
§ 45Z(b)(1)(B)(i). If the applicable emissions rate table establishes the emissions rate
for a non-SAF transportation fuel, a taxpayer producing such fuel would determine the
fuel’s emissions rate using the 45ZCF-GREET model, as directed by the applicable
emissions rate table. If the applicable emissions rate table establishes the emissions
rate for a SAF transportation fuel, a taxpayer producing such fuel would determine the
fuel’s emissions rate using the most recent version of the CORSIA Default Life Cycle
Emissions Values for CORSIA Eligible Fuels lifecycle approach (CORSIA Default) or
the CORSIA Methodology for Calculating Actual Life Cycle Emissions Values lifecycle
approach (CORSIA Actual), with the agreement of the United States, or the 45ZCF-
GREET model, as directed by the applicable emissions rate table. The proposed
regulations would also clarify that, for a given type and category of SAF transportation
fuel, a taxpayer must use the same methodology to calculate lifecycle GHG emissions
associated with all stages of SAF transportation fuel production, from fuel feedstock
production through distribution.
Proposed § 1.45Z-2(e)(3)(iii)(B) would provide that in the 45ZCF-GREET model,
for purposes of accounting for emissions associated with natural gas alternatives (as a
production input or as the transportation fuel produced), rules similar to the rules under
§ 45V apply, unless otherwise specified by the 45ZCF-GREET model with respect to
technical modeling issues that are subsequently identified by the DOE or technical
differences arising from the application of the § 45V rules to the 45ZCF-GREET model.

- 9 -
Section 1.45V-4(f)(3)(v) provides generally that for purposes of determining the
lifecycle GHG emissions rate of a process that uses methane derived from biogas
sourced from animal waste, the associated emissions must use an alternative fate
derived from the national average of all animal waste management practices.
4
That
approach is incompatible with § 70521(c) of the OBBBA, requiring distinct emissions
rates, based on the specific animal manure feedstock, for transportation fuels derived
from animal manure. Section 3.02 of this notice provides guidance on the emissions
associated with natural gas alternatives derived from animal manure for § 45Z
purposes, implementing this OBBBA amendment.
SECTION 3. CERTAIN EMISSIONS ACCOUNTING
.01 Regenerative agriculture practices; safe harbor.

The USDA published a beta version of the USDA Feedstock Carbon Intensity
Calculator (USDA FD-CIC) in January 2025. The preamble to the § 45Z NPRM
explains that, following publication of the final version of USDA FD-CIC, the Treasury
Department and the IRS anticipate that a § 45Z-specific version of the Feedstock
Carbon Intensity Calculator (FD-CIC) module would be included as an input to the
DOE’s 45ZCF-GREET model (45ZCF FD-CIC) used for calculating carbon intensity
adjustments under § 45Z for feedstocks that are produced using certain low-carbon
agricultural practices. The preamble also notes that the Treasury Department and the
IRS anticipate that 45ZCF FD-CIC may be used for fuel produced and sold in 2025
even though 45ZCF FD-CIC likely would be published in 2026.
In June 2026, the USDA published an updated version of USDA FD-CIC,

4
The term “alternative fate” has the same meaning as in § 1.45V-4(f)(2)(i).

- 10 -
available at https://www.usda.gov/usda-fdcic, alongside related final Technical
Guidelines for the Production of Regenerative Agricultural Biofuel Feedstocks (91 F.R.
39334, June 29, 2026) (USDA technical guidelines). A 2026 version of 45ZCF FD-CIC
is forthcoming as part of the 45ZCF-GREET model.
For fuel produced in 2025, a taxpayer may use the 2026 version of 45ZCF FD-
CIC to determine the emissions associated with feedstocks produced using low-carbon
agricultural practices, provided the taxpayer satisfies all requirements for such practices
under the USDA technical guidelines in 7 CFR part 2100, including the chain of custody
standards in 7 CFR 2100.030 through 2100.035 and the audit and verification standards
in 7 CFR 2100.040 and 2100.041. The Treasury Department and the IRS are aware
that for fuel produced in 2025 and 2026, the primary feedstock produced using low-
carbon agricultural practices was likely planted before the publication of the final USDA
technical guidelines. As such, for fuel produced in 2025 and 2026, the requirements
under 7 CFR 2100.060, regarding the pre-application development of a nutrient budget,
are deemed satisfied for purposes of § 45Z. However, a taxpayer must be able to
substantiate the application of any nutrients (such as nitrogen, phosphorus, and
potassium) and measurable nutrient sources and removals that the taxpayer inputs into
45ZCF FD-CIC. A taxpayer must also keep records sufficient to substantiate its claim
for the § 45Z credit. See proposed § 1.45Z-4(g)(1)–(2).
.02 Distinct emissions rates for specific animal manure feedstocks.

As discussed in sections 2.03 and 2.04(3) of this notice, § 45Z(b)(1)(B)(v)(I)
directs the Secretary to provide, for transportation fuels derived from animal manure,
distinct emissions rates based on the specific animal manure feedstock.

- 11 -
(1) Specific animal manure feedstocks.
Section 45Z(b)(1)(B)(v)(I) provides that specific animal manure feedstocks may
include dairy manure, swine manure, and poultry manure (listed manures). Section
45Z(b)(1)(B)(v)(I) contemplates specific animal manure feedstocks other than the listed
manures (unlisted manures), as are determined appropriate by the Secretary. The
Treasury Department and the IRS may provide future guidance for determining the
emissions rate of fuels derived from unlisted manures, including specific alternative
fates. However, the Treasury Department and the IRS anticipate that some unlisted
manures will lack technical data to determine an alternative fate for a specific animal
manure feedstock.
The Treasury Department and the IRS anticipate that an update to the 45ZCF-
GREET model including dairy manure and swine manure as distinct primary feedstocks
is forthcoming. As such, dairy manure and swine manure are included as primary
feedstocks in the 2026 emissions rate table in the Appendix to this notice.
A taxpayer producing a transportation fuel derived from an animal manure not
included in the 2026 emissions rate table may submit a PER petition with the Secretary
as provided by § 45Z(b)(1)(D) and in accordance with proposed § 1.45Z-2(f). However,
the Treasury Department and the IRS anticipate that the 45ZCF-GREET model will be
further updated in 2026 to include poultry manure and beef manure as primary
feedstocks. Accordingly, producers of fuels derived from poultry manure and beef
manure are encouraged to await this subsequent 45ZCF-GREET model update and to
postpone potential submission of any PER petition for such fuels.
(2) Alternative fate.

- 12 -
The Treasury Department and the IRS, in consultation with the DOE and the
USDA, have determined that in certain instances a distinct emissions rate for a
transportation fuel derived from animal manure may be determined within the 45ZCF-
GREET model on the basis of the farm-specific prior manure management practices
applied to each specific animal manure feedstock, as described below.
A taxpayer producing a transportation fuel derived from animal manure may use
an alternative fate reflecting farm-specific prior manure management practices for the
animal manure from which the taxpayer derived its transportation fuel. For purposes of
determining such alternative fate, a “farm” is any animal feeding operation, with or
without a nutrient management plan, or other animal operation with a nutrient
management plan. Farm-specific prior manure management practices depend on the
animal manure, and may include manure storage in uncovered lagoons, deep pits,
liquid/slurry, pasture/range/paddock, dry lot, and solid storage.
A taxpayer producing a fuel derived from an animal manure determines a distinct
emissions rate by inputting into the 45ZCF-GREET model the number of animals by
type and share of manure managed using each prior practice in place immediately
preceding the earlier of: (i) the commencement date of any anaerobic digester
operation
5
or (ii) September 8, 2026. If a farm diverted manure to an off-farm anaerobic
digester, the commencement date is the date the farm first began diverting manure to
any off-site anaerobic digester. A taxpayer will provide the number of animals by type
and the share of manure managed using each practice, including the quantity routed to

5
For purposes of this determination, an anaerobic digester is considered operational on the date at which
the system begins capturing, productively using, and/or destroying biogas after an initial start-up period.
The initial start-up period must not exceed nine months.

- 13 -
an anaerobic digester, in the taxable year of production. This information is collectively
used to calculate the avoided emissions in the 45ZCF-GREET model for prior manure
management practices based on the specific animal manure feedstock.
A taxpayer must be able to substantiate such farm-specific prior manure
management practices for all collected manure if such data are used to establish an
alternative fate. A taxpayer that cannot substantiate the farm-specific prior manure
management practices of a given farm will not have avoided emissions included in the
45ZCF-GREET model for such farm’s portion of the taxpayer’s manure inputs. For
more information regarding substantiation of emissions rates and the related safe
harbor, see proposed § 1.45Z-4(g)(1)–(2).
The 45ZCF-GREET model will not provide a farm-specific alternative fate with
respect to animal manure sourced from a new farm (a farm that begins operations after
September 8, 2026) until the Treasury Department and the IRS issue further guidance
on this issue. As previously explained, the farm-specific alternative fate for a specific
animal manure feedstock reflects the avoided emissions from utilizing an anaerobic
digester as compared to the prior manure management practices for a given animal
manure on the farm. Given how the farm-specific alternative fate is calculated, a new
farm, which necessarily has no existing manure management practices, could be
incentivized to select the highest emitting practices on startup. Such intentional inflation
of avoided emissions, and in turn the § 45Z credit amount, is contrary to the language of
§ 45Z and its incentivization of cleaner fuel production. The Treasury Department and
the IRS are studying how a distinct emissions rate for transportation fuel derived from
animal manures sourced from a new farm may be determined in a manner that

- 14 -
mitigates these concerns.
SECTION 4. TRANSITION GUIDANCE FOR OBBBA AMENDMENTS
.01 In general.

The Treasury Department and the IRS are aware of the need for guidance on
how to apply the OBBBA amendments discussed in section 2.03 of this notice by
taxpayers using a version of an allowed methodology that does not reflect these
OBBBA amendments. This section 4 provides transition guidance on how to apply
these OBBBA amendments in such cases.
The first version of the 45ZCF-GREET model to incorporate some of these
OBBBA amendments was released on June 12, 2026 (June 2026 version of the 45ZCF-
GREET model). Generally, a taxpayer using a pre-June 2026 version of the 45ZCF-
GREET model must generate one result for transportation fuel produced on or before
December 31, 2025, and another result, modified as specified in section 4.02 of this
notice, for transportation fuel produced after December 31, 2025. Utilizing separate
results implements the OBBBA’s amendments and effective dates.
.02 Application of OBBBA amendments in prior model versions.

(1) ILUC exclusion.
Pursuant to § 45Z(b)(1)(B)(iv), a taxpayer producing a transportation fuel after
December 31, 2025, must determine an emissions rate that does not include ILUC
emissions. For taxpayers using a version of the 45ZCF-GREET model that includes
ILUC emissions to determine the emissions rate for a transportation fuel produced after
December 31, 2025, the ILUC value published in the 45ZCF-GREET model must be
subtracted from the Total Life Cycle Analysis Results (Total LCA Results). To make this

- 15 -
adjustment, a taxpayer must subtract the ILUC value in the calculated results table from
the Total LCA Results, expressed in grams of CO
2
e per megajoule. The adjusted Total
LCA Results must then be multiplied by a factor of 1.055 to convert the Total LCA
Results into kg of CO
2
e per mmBTU.
Taxpayers that use CORSIA Default to determine the emissions rate for a SAF
transportation fuel produced after December 31, 2025, must exclude the relevant
Default ILUC value listed in CORSIA Default.
Taxpayers that use CORSIA Actual to determine the emissions rate for a SAF
transportation fuel produced after December 31, 2025, must exclude any ILUC value
included as part of the CORSIA Actual verification process. See section 2.04(3) of this
notice for more information on identifying which version of CORSIA Default or CORSIA
Actual a taxpayer must use.
(2) Foreign feedstock limitation.
Versions of the 45ZCF-GREET model have included pathways for transportation
fuel derived from primary feedstocks produced or grown outside the United States,
Mexico, or Canada. However, pursuant to § 45Z(f)(1)(A)(iii), a taxpayer may not claim a
§ 45Z credit for any such fuel produced after December 31, 2025. See section 2.03 of
this notice. The § 45Z NPRM also discusses how, after the OBBBA, prohibited foreign
feedstocks would be those that originate from a source and/or are purchased from an
aggregator located outside the United States, Canada, or Mexico (imported non-
Canadian/Mexican).
As discussed in the preamble to the § 45Z NPRM, the Treasury Department and
the IRS remain concerned about the ability to reliably distinguish between imported

- 16 -
used cooking oil (UCO) and palm oil, and the resulting risk of crediting ineligible fuels.
The preamble to the § 45Z NPRM also states that, as a result, pathways that use
imported non-Canadian/Mexican UCO will not be available in the 45ZCF-GREET model
until the Treasury Department and the IRS publish further guidance. This section
4.02(2) contains that guidance.
Pre-June 2026 versions of the 45ZCF-GREET model included United States
UCO as a primary feedstock for certain pathways. The OBBBA’s restriction on imported
non-Canadian/Mexican feedstocks permits a § 45Z credit for transportation fuel
produced from Canadian and Mexican UCO. Accordingly, the June 2026 version of the
45ZCF-GREET model added Canadian and Mexican UCO as another primary
feedstock for pathways that include United States UCO as a primary feedstock. The
calendar year 2026 emissions rate table in the Appendix to this notice also does so. A
taxpayer producing a transportation fuel from Mexican or Canadian UCO must use a
version of the 45ZCF-GREET model that includes such primary feedstocks to determine
the emissions rate of such fuel. The first emissions rate for such fuel, established in the
June 2026 version of the 45ZCF-GREET model, relates back for such fuel produced
since January 1, 2025. See section 2.04(1) of this notice.
Transportation fuel produced after December 31, 2025, from imported non-
Canadian/Mexican UCO, is not eligible for the § 45Z credit. However, for fuel produced
in 2025 only, a taxpayer producing a transportation fuel from imported non-
Canadian/Mexican UCO must use the applicable pathway in a forthcoming version of
the 45ZCF-GREET model for imported non-Canadian/Mexican UCO. Although
concerns about the reliability and substantiation of imported non-Canadian/Mexican

- 17 -
UCO persist, they are limited in scope, and partly mitigated, by the OBBBA’s prohibition
on imported non-Canadian/Mexican UCO as a feedstock for transportation fuel
produced after December 31, 2025. Further, because any producer using such
imported non-Canadian/Mexican UCO would have already produced the fuel before
these pathways were available, and would likely have access to contemporaneous
records for 2025 production, the potential for fraud or falsified records is lower.
The § 45Z NPRM requested comments on appropriate substantiation and
recordkeeping requirements for feedstocks imported from Canada and Mexico,
including UCO, to ensure such feedstocks meet the statutory sourcing requirement. A
taxpayer producing a transportation fuel from UCO must keep records sufficient to
substantiate its claim for the § 45Z credit, including any specific requirements for UCO
in the final § 45Z regulations. See proposed § 1.45Z-4(g)(1)–(2).
(3) Animal manure.

Distinct emissions rates based on the specific animal manure feedstock are
applicable for all transportation fuel derived from animal manure produced after
December 31, 2025, as provided by § 45Z(b)(1)(B)(v) and sections 2.03 and 3.02 of this
notice. As discussed in section 3.02(1) of this notice, versions of the 45ZCF-GREET
model providing such distinct emissions rates are anticipated. A taxpayer producing a
transportation fuel derived from animal manure after December 31, 2025, must use
such a version of the 45ZCF-GREET model to determine the emissions rate of such fuel
produced after December 31, 2025. See section 2.04 of this notice. A taxpayer must
use a version of the 45ZCF-GREET model reflecting an alternative fate derived from the
national average of all animal waste management practices to determine the emissions

- 18 -
rate of a transportation fuel derived from animal manure produced on or before
December 31, 2025. See section 2.04 of this notice.
(4) Negative emissions rates.
Negative emissions rates are prohibited for transportation fuel produced after
December 31, 2025, unless derived from animal manure. Section 4.02(3) of this notice
discusses transportation fuel derived from animal manure produced in 2026. A
taxpayer using a pre-June 2026 version of the 45ZCF-GREET model to determine the
emissions rate of any other transportation fuel produced in 2026 must adjust any
negative result up to zero.
SECTION 5. EFFECTIVE DATE
This notice is effective on and after September 8, 2026. For additional guidance
regarding the application of the calendar year 2026 emissions rate table, see proposed
§ 1.45Z-2(e)(2) and sections 2.04 and 4 of this notice.
SECTION 6. DRAFTING INFORMATION
The principal author of this notice is Andrew Clark of the Office of Associate
Chief Counsel (Energy, Credits, and Excise Tax). For further information regarding this
notice contact Mr. Clark at (202) 317-6855 (not a toll-free number).

- 1 -
Appendix

Section 45Z Emissions Rate Table for Calendar Year 2026

Type of Fuel
Category of Fuel
Allowed
Methodology for
Determination of
Emissions Rate*
Pathway Primary Feedstock
Ethanol Fermentation
U.S. corn starch
Most recent version of
the 45ZCF-GREET
model
U.S. sorghum grain
Brazilian sugarcane (for use as a
feedstock for SAF Alcohol-to-Jet
(ATJ) pathway only)
1
U.S. corn stover
Biodiesel Transesterification
U.S. soybean oil
Most recent version of
the 45ZCF-GREET
model
U.S./Canadian canola
oil/rapeseed oil
U.S./Canadian/Mexican used
cooking oil (UCO)
Other imported UCO (non-
Canadian/Mexican)
1

U.S./Canadian/Mexican tallow
Other imported tallow (non-
Canadian/Mexican)
1

U.S. distillers corn oil (DCO)
U.S. distillers sorghum oil (DSO)
U.S. carinata oil (intermediate
crop)
U.S. camelina oil (intermediate
crop)
U.S. pennycress oil (intermediate
crop)

Renewable Diesel

Hydroprocessed
esters and fatty
acids (HEFA)
U.S. soybean oil
Most recent version of
the 45ZCF-GREET
model
U.S./Canadian canola
oil/rapeseed oil
U.S./Canadian/Mexican UCO
Other imported UCO (non-
Canadian/Mexican)
1

U.S./Canadian/Mexican tallow
Other imported tallow (non-
Canadian/Mexican)
1

U.S. DCO
U.S. DSO
U.S. carinata oil (intermediate
crop)
U.S. camelina oil (intermediate
crop)
U.S. pennycress oil (intermediate
crop)
ATJ
Ethanol (from fermentation
pathways listed above)
3

- 2 -

Gasification &
Fischer-Tropsch
U.S. corn stover
Renewable Natural
Gas
Anaerobic
Digestion and
Biogas Upgrading
U.S. wastewater sludge
Most recent version of
the 45ZCF-GREET
model
U.S. animal manures (generic
alternative fate)
1

U.S. dairy manure
2
U.S. swine manure
2
U.S. landfill gas
U.S. food scraps
U.S. corn stover
U.S. grain stillage
U.S. fats, oils, and greases (FOG)
and septage
U.S. DCO
U.S. DSO
U.S. mixed high-moisture organic
wastes
Alternative Natural
Gas
Coal Mine
Methane Capture
and Upgrading
U.S. coal mine methane Most recent version of
the 45ZCF-GREET
model
Propane HEFA
U.S. soybean oil
Most recent version of
the 45ZCF-GREET
model
U.S./Canadian canola
oil/rapeseed oil
U.S./Canadian/Mexican UCO
Other imported UCO (non-
Canadian/Mexican)
1

U.S./Canadian/Mexican tallow
Other imported tallow (non-
Canadian/Mexican)
1

U.S. DCO
U.S. DSO
U.S. carinata oil (intermediate
crop)
U.S. camelina oil (intermediate
crop)
U.S. pennycress oil (intermediate
crop)
Naphtha HEFA
U.S. soybean oil
Most recent version of
the 45ZCF-GREET
model
U.S./Canadian canola
oil/rapeseed oil
U.S./Canadian/Mexican UCO
Other imported UCO (non-
Canadian/Mexican)
1

U.S./Canadian/Mexican tallow
Other imported tallow (non-
Canadian/Mexican)
1

U.S. DCO
U.S. DSO
U.S. carinata oil (intermediate

- 3 -
1
For fuels produced before January 1, 2026, only
2
For fuels produced after December 31, 2025, only
3
Subject to the limitation in § 45Z(d)(5)(A)(iv)
* See section 2.04(3) of this notice
** The 45VH2-GREET model and the 45VH2-GREET User Manual are available at
https://www.energy.gov/cmei/greet
crop)
U.S. camelina oil (intermediate
crop)
U.S. pennycress oil (intermediate
crop)
Hydrogen
Various, as
defined in the
user manual for
the most recent
45VH2-GREET
model**
Various, as defined in the user
manual for the most recent
45VH2-GREET model
3
Calculate well-to-gate
emissions using the
45VH2-GREET
model; then calculate
the full well-to-wheel
emissions using the
most recent version of
the 45ZCF-GREET
model. See the
45ZCF-GREET User
Manual for additional
instructions.
Sustainable Aviation
Fuel (SAF)
HEFA
U.S. soybean oil
Most recent version of
one of the following:
1) the 45ZCF-GREET
model or 2) CORSIA
Default or CORSIA
Actual
U.S./Canadian canola
oil/rapeseed oil
U.S./Canadian/Mexican UCO
Other imported UCO (non-
Canadian/Mexican)
1

U.S./Canadian/Mexican tallow
Other imported tallow (non-
Canadian/Mexican)
1

U.S. DCO
U.S. DSO
U.S. carinata oil (intermediate
crop)
U.S. camelina oil (intermediate
crop)
U.S. pennycress oil (intermediate
crop)
ATJ
Ethanol (from fermentation
pathways listed above)
3

Gasification &
Fischer-Tropsch
U.S. corn stover
Any SAF pathway
that is not
represented
above and is
established in
CORSIA Default
or CORSIA Actual
Any feedstock for such a
pathway
3

Most recent version of
CORSIA Default or
CORSIA Actual