Case Studies
Clean Fuel Production Credit: Opportunities & Obligations After §45Z Changes
Major revisions under the One, Big, Beautiful Bill reshape clean fuel tax credits — we break down what you need to know to benefit and stay compliant.
By NomadicTax Research Team • 5-8 min read • March 8, 2026
## What Is the Section 45Z Clean Fuel Production Credit?
This is a tax credit enacted under Public Law 119-21 (One, Big, Beautiful Bill) for **domestic producers of clean transportation fuel**. It rewards clean energy innovation by offering credit for fuel produced after **December 31, 2024**, but sold no later than **December 31, 2029**. ([irs.gov](https://www.irs.gov/newsroom/treasury-irs-issue-proposed-regulations-on-the-clean-fuel-production-credit-under-the-one-big-beautiful-bill?utm_source=openai))
## Key Changes and New Rules Under OBBB
- **Geographic feedstock restriction**: Fuel must be derived from feedstocks grown or produced in **the U.S., Mexico, or Canada** after **December 31, 2025**. ([irs.gov](https://www.irs.gov/newsroom/treasury-irs-issue-proposed-regulations-on-the-clean-fuel-production-credit-under-the-one-big-beautiful-bill?utm_source=openai))
- **Prohibited foreign entities**: Specified foreign or foreign-influenced entities (as defined in the law) are disallowed from claiming the credit for tax years beginning after respective effective dates. ([irs.gov](https://www.irs.gov/newsroom/treasury-irs-issue-proposed-regulations-on-the-clean-fuel-production-credit-under-the-one-big-beautiful-bill?utm_source=openai))
- **Emissions rate changes**: Negative emissions rates (e.g., carbon capture or offsets) are **prohibited** after December 31, 2025 — except for fuel derived from animal manure. Additionally, indirect land use changes are excluded from emissions calculations. ([irs.gov](https://www.irs.gov/newsroom/treasury-irs-issue-proposed-regulations-on-the-clean-fuel-production-credit-under-the-one-big-beautiful-bill?utm_source=openai))
- **Sustainable Aviation Fuel (SAF)**: The special rate for SAF is eliminated; SAF fuel for sales after **December 31, 2025** receives the same rates as other transportation fuel. ([irs.gov](https://www.irs.gov/newsroom/treasury-irs-issue-proposed-regulations-on-the-clean-fuel-production-credit-under-the-one-big-beautiful-bill?utm_source=openai))
## Claiming the Credit: Requirements & Process
- Producers must be **registered** with the IRS via **Form 637**, using Activity Letter “CN” (non-SAF) or “CA” (SAF) before production begins. ([irs.gov](https://www.irs.gov/newsroom/treasury-irs-issue-proposed-regulations-on-the-clean-fuel-production-credit-under-the-one-big-beautiful-bill?utm_source=openai))
- The credit amount per gallon (or gallon equivalent) is multiplied by an **emissions factor** determined under new and existing rules. ([irs.gov](https://www.irs.gov/newsroom/treasury-irs-issue-proposed-regulations-on-the-clean-fuel-production-credit-under-the-one-big-beautiful-bill?utm_source=openai))
- Fuel must be **produced domestically**, **sold** by the producer in a qualifying transaction, and meet all timing and feedstock standards. ([irs.gov](https://www.irs.gov/newsroom/treasury-irs-issue-proposed-regulations-on-the-clean-fuel-production-credit-under-the-one-big-beautiful-bill?utm_source=openai))
## Example Scenario
Suppose you operate a biodiesel plant in Texas:
- You produce non-SAF clean fuel using feedstock sourced in Mexico, starting in early **2026**.
- Negative emissions rates aren’t allowed unless your feedstock is animal manure. So, unless your methodology is tightly aligned with the law, you may only get credit under standard emissions rates.
- You must register via Form 637 before production, and your fuel must be sold to an unrelated party. If you have a contract, make sure it reflects compliance with feedstock and domestic production rules.
## What Actions Should Fuel Producers Take Now?
- **Register** immediately if not yet registered — Form 637 activity letters CN or CA needed. Timing matters.
- **Review supply chain** — ensure feedstocks are eligible (U.S./Mexico/Canada) and check for possible prohibited entity exposure.
- **Calculate emissions rates** carefully — prepare to discard indirect land-use changes and focus on direct emissions unless dealing with animal manure feedstocks.
- **Monitor rulemaking** — regulations are proposed (as of IR-2026-20), and issuances related to anti-abuse and attribution are expected. Stakeholder comments are open. ([irs.gov](https://www.irs.gov/newsroom/treasury-irs-issue-proposed-regulations-on-the-clean-fuel-production-credit-under-the-one-big-beautiful-bill?utm_source=openai))
By aligning operations with these new rules, producers can access significant incentives for clean fuel — but any misstep in registration, timing, or documentation risks losing eligibility.