SECTION 4. REGISTRATION — Internal Revenue Bulletin 2024-26

PRODUCER OF CLEAN FUEL

.01 Registration generally . (1) Statutory registration requirement . Section 45Z(f)(1)(A)(i)(1) provides that no clean fuel production credit can be determined under § 45Z(a) with respect to any transportation fuel unless the taxpayer is registered as a producer of clean fuel under § 4101 at the time of production. ⁴ See § 48.4101-1 of the Manufacturers and Retailers Excise Tax Regulations for rules relating to registration under § 4101. ⁵

(2) Registration letter; timing of appli- cations for registration . A person is registered for purposes of § 45Z(f)(1)(A)(i) (1) only if the IRS has issued a registration letter to the person and the registration has not been revoked or suspended. To be eligible to claim the § 45Z credit for production starting January 1, 2025, a taxpayer must have a signed registration letter dated on or before January 1, 2025. For example, if a taxpayer receives a letter of registration dated June 30, 2025, the taxpayer cannot claim the § 45Z credit for any transportation fuel produced and sold by the taxpayer before June 30, 2025, even if all other statutory requirements for the § 45Z credit are satisfied prior to that date. That taxpayer can only claim the § 45Z credit for transportation fuel produced and sold on or after June 30, 2025.

Given the requirement that a taxpayer must be registered at the time of production to claim the § 45Z credit, taxpayers are encouraged to apply for registration as soon as possible to give the IRS sufficient time to process registration applications for the § 45Z credit. The IRS intends to process completed applications for registration received by July 15, 2024, such that an eligible taxpayer can receive its letter of registration by January 1, 2025.

4 Section 45Z(f)(1)(A)(i)(I) provides that “[n]o clean fuel production credit shall be determined under § 45Z with respect to any transportation fuel unless the taxpayer is registered as a producer of clean fuel under § 4101 at the time of production,…”. Section 13704(b)(5) of the IRA provided that for transportation fuel produced after December 31, 2024, “Section 4101(a) (1), as amended by the preceding provisions of this Act, is amended by inserting the phrase ‘every person producing a fuel eligible for the clean fuel production credit (pursuant to section 45Z)’ after ‘section 6426(k)(3)).’” However, § 4101(a)(1) does not reference § 6426(k)(3). The Office of Law Revision Counsel of the U.S. House of Representatives, whose functions include preparing and publishing periodically a new edition of the United States Code, executed the provision by making the insertion after "section 40B)," to reflect the probable intent of Congress.

5 The Treasury Department and the IRS intend to update the regulations under § 4101 to reflect the registration requirement in § 45Z(f)(1)(A)(i)(I).

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The IRS intends to quickly process applications received after July 15, 2024, but cautions that a taxpayer that applies for registration after that date is less likely to receive its registration by January 1, 2025. In no event can the IRS guarantee that any application for registration will be processed by a certain date.

(3) Effect of registration letter . Registration is one of the requirements for a taxpayer to be eligible to claim the § 45Z credit. The taxpayer and the fuel(s) that the taxpayer produces must also meet the other § 45Z requirements for the taxpayer to be eligible to claim the § 45Z credit. A registration letter is not a determination by the IRS that the registrant may claim the § 45Z credit. For example, a registration for Activity Letter “CN” issued to a taxpayer producing biodiesel is not a determination that the biodiesel meets the definition of transportation fuel under § 45Z(d)(5) or that the facility where the taxpayer produces such biodiesel meets the definition of a qualified facility under § 45Z(d)(4).

(4) Procedures and information for registering generally . Application for registration is made on Form 637, “Application for Registration (for Certain Excise Tax Activities),” under Activity Letter “CN” (for a producer of non-SAF transportation fuel), or Activity Letter “CA” (for a producer of SAF), or both, in accordance with the instructions for that form. The IRS is revising Form 637 to add Activity Letters “CN” and “CA.” An applicant may apply for registration under more than one Activity Letter on a single Form 637.

Until the revised Form 637 is released, applicants may use the current Form 637 by writing in Activity Letter “CN” or Activity Letter “CA,” or both, as applicable, and providing the corresponding information required by section 4.02 and 4.03 of this notice. (5) Transportation fuel; feedstocks; co-processor registration . The information in this section 4.01(5) and Appendix A is provided solely for purposes of applications for registration and is not determinative of whether a fuel is transportation fuel. Qualification of a fuel as transportation fuel depends on the specific facts and circumstances, including the emissions rate of such fuel.

(A) Non-SAF transportation fuel . In consultation with the Department of Energy (DOE), the Treasury Department and the IRS anticipate that low-GHG biodiesel, low-GHG butanol, low-GHG diesel fuel, low-GHG dimethyl ether, low-GHG ethanol, low-GHG gasoline, low-GHG hydrogen, low-GHG LPG, lowGHG methanol, and low-GHG natural gas may qualify as non-SAF transportation fuel taking into consideration the emissions rate threshold in § 45Z(d)(5)(A)(ii). See section 3.03 of this notice for definitions of these types of fuel. Most fuels derived from palm fatty acid distillates, petroleum, natural gas, and coal (including lignite) are not expected to qualify as non-SAF transportation fuel based on the § 45Z(d)(5)(A)(ii) emissions rate threshold. A producer of non-SAF transportation fuel not defined in section 3.03 of this notice should submit an application for registration if such producer anticipates such fuel to be eligible for the § 45Z credit.

(B) Co-processed SAF . For SAF produced by co-processing petroleum with SAF FT hydrocarbons, the co-processor is the party that applies for registration under this notice.

(C) Feedstocks used to produce trans- portation fuel; additional fuels and feed- stocks . In Appendix A, the Treasury Department and the IRS, in consultation with the DOE, have identified the feedstocks and feedstock types associated with the varieties of fuel that may qualify as transportation fuel. The Treasury Department and the IRS may provide guidance at a later time about additional fuels (and the feedstocks for such fuels) that may be eligible for the § 45Z credit.

.02 Registration procedure and require- ments for producers of non-SAF transpor- tation fuel eligible for the § 45Z credit .

(1) Procedure for registering . Until the revised Form 637 is released, applicants producing non-SAF transportation fuel eligible for the § 45Z credit may use the current Form 637 by writing in Activity Letter “CN” and providing the following information:

(A) Each type of non-SAF transportation fuel and the annual volume of each type of non-SAF transportation fuel the applicant produces. If a type of non-SAF transportation fuel the applicant produces

is not described in section 4.01(5)(A) of this notice, state “Other” and provide a description of the fuel;

(B) The feedstock(s) and country of origin of each feedstock used to produce each type of non-SAF transportation fuel the applicant produces;

(D) Each production facility’s annual fuel production capacity, and whether the applicant’s production facilities are operational and currently producing volumes of non-SAF transportation fuel;

(E) The names and addresses of any person(s) acting for the applicant as an agent or broker in buying, selling, or transporting any non-SAF transportation fuel;

(F) The business entities to which the applicant sells non-SAF transportation fuel;

(G) The business entities from or with which the applicant buys, trades, transfers, or exchanges any non-SAF transportation fuel;

(H) The annual volume of non-SAF transportation fuel the applicant buys, sells, trades, transfers, or exchanges; and

(I) A statement indicating under which ASTM standard(s), SAE standard(s), or both, the applicant produces non-SAF transportation fuel.

(2) Requirements . The IRS will register an applicant with Activity Letter “CN” only if the IRS (A) concludes that the applicant is engaged as a producer of non-SAF transportation fuel that may be eligible for the § 45Z credit, or is likely to become so engaged within a reasonable time after being registered; and (B) is satisfied with the filing, deposit, payment, reporting, and claim history for all federal taxes of the applicant and any related person (as defined in § 48.4101-1(b)(5)).

.03 Registration procedure and requirements for producers of SAF eligi- ble for the § 45Z credit .

(1) Procedure for registering . Until the revised Form 637 is released, applicants producing SAF eligible for the § 45Z credit may use the current Form 637 by writing in Activity Letter “CA” and providing the following information:

(A) A statement indicating whether the applicant produces SAF under an ASTM D7566 Annex or ASTM D1655 Annex A1, and if applicable, the specific ASTM

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D7566 Annex under which the SAF synthetic blending component is produced;

(B) The feedstock(s) and country of origin of each feedstock used to produce the SAF the applicant produces;

(D) The location(s) and a description of the applicant’s production facilities;

(E) Each production facility’s annual fuel production capacity, and whether the applicant’s production facilities are operational and currently producing volumes of SAF;

(F) The names and addresses of any person(s) acting for the applicant as an agent or broker in buying, selling, or transporting any SAF;

(G) The business entities to which the applicant sells SAF;

(H) The business entities from or with which the applicant buys, trades, transfers, or exchanges any SAF; and

(I) The annual volume of SAF the applicant buys, sells, trades, transfers, or exchanges.

(2) Requirements . The IRS will register an applicant with Activity Letter “CA” only if the IRS (A) concludes that the applicant is engaged as a producer of SAF that may be eligible for the § 45Z credit, or is likely to become so engaged within a reasonable time after becoming registered; and (B) is satisfied with the filing, deposit, payment, reporting, and claim history for all federal taxes of the applicant and any related person (as defined in § 48.4101-1(b)(5)).