The US Treasury and IRS have released proposed regulations for the clean fuel production credit under the One, Big, Beautiful Bill, outlining eligibility, calculation, and certification requirements, while introducing key changes including extended credit duration, feedstock limits, and anti-abuse measures.
The Department of the Treasury and the Internal Revenue Service (IRS) announced on 3 February 2026 the proposed regulations for domestic producers of clean transportation fuel to determine their eligibility for and calculate the clean fuel production credit under the One, Big, Beautiful Bill. The new law made important changes to what is often referred to as the 45Z credit.
The clean fuel production credit provides businesses an income tax credit for clean transportation fuel produced domestically after 31 December 2024, and sold by 31 December 2029. To claim the credit, taxpayers must be registered with the IRS using Form 637, Application for Registration (For Certain Excise Tax Activities) at the time of production.
The proposed regulations provide guidance on the determination of clean fuel production credits, emissions rates, and certification and registration requirements. They provide further certainty and clarity for taxpayers and address key issues raised by stakeholders.
What’s new under the OBBB
Today’s guidance also proposes rules to implement certain OBBB changes to the clean fuel production credit. OBBB changed the clean fuel production credit to:
- Extend the credit to 31 December 2029;
- Limit feedstocks to those grown or produced in the US, Mexico, or Canada;
- Add prohibited foreign entity restrictions;
- Broaden sale attribution for fuel sold through related intermediaries;
- Eliminate the special rate for sustainable aviation fuel;
- Add an anti-abuse provision to prevent double crediting;
- Prohibit negative emissions rates except for fuels derived from animal manure;
- Require feedstock-specific emissions rates for fuels derived from animal manure; and
- Exclude indirect land use changes from emissions rates.
Treasury and IRS invite public comments
Treasury and IRS welcome comments and requests to speak at the public hearing on these proposed regulations. Commenters are encouraged to use the Federal e-Rulemaking portal to submit comments (indicate “IRS” and “REG-121244-23”).
A public hearing has been scheduled as described in the “Comments and Public Hearing” section. Paper submissions should be sent to: CC:PA:01:PR (REG-121244-23), Room 5503, Internal Revenue Service, P.O. Box 7604, Ben Franklin Station, Washington, DC 20044.
