IRS PTC 45Z Tax Credit Opportunities and Compliance for RNG Producers

The Clean Fuel Production Tax Credit (PTC), also called the 45Z after the section of the act in which it was passed, was implemented on January 1, 2024 as part of the Inflation Reduction Act (IRA) of 2022.  The IRA contained additional low carbon fuel tax credits and incentives for carbon capture and utilization (45Q), production of renewable electricity (45Y) and low carbon hydrogen production (45V). These rules were substantially altered as part of the “One Big Beautiful Bill Act” (OBBBA) of 2025.

The PTC replaced the fuel Blender’s Tax Credit (BTC).  The BTC provided tax incentives for blenders of low carbon fuel with traditional fossil fuels.  With the implementation of the PTC, producers of low carbon fuels based in the United States would be granted tax credits, rather than fuel blenders.  This significantly expanded crediting opportunities for renewable natural gas (RNG) as it removed the requirement for fossil fuel blending for transportation service.

The PTC is administered by the United States Internal Revenue Service (IRS) and is generated during the annual federal tax return process.  Entities eligible to generate this tax credit:

•  Are low carbon or biogenic fuel producers that are:
  • Located within the United States;
  • Using feedstock sourced from the United States, Canada or Mexico (starting January 1, 2026); an
  • Producing fuel that meets specifications for transportation fuel use;
• Are registered with the IRS using form 637 for certain excise tax activities; and
• Sell fuel to a third party.

The PTC applies to all low carbon fuel produced within the US even if the fuel is later exported.  Additionally, fuel producers do not need to prove that the fuel is used for transportation service but do need to meet transportation fuel specifications.  This means that RNG producers just have to show that they have injected their gas into a common carrier pipeline to generate the credit.

Credit value is based on the fuel’s calculated carbon intensity (CI), or emissions per unit of energy produced, using the 45ZCF-GREET model.  The IRS, in partnership with the US Department of Energy (DoE), has provided models for landfill, wastewater or animal manure based RNG.  These models, while simplified versions of the larger GREET model, can be difficult to understand and run and often require complex data analysis prior to input.  Additionally, there are third party verification requirements that must be completed both on the model input data as well as the facility’s qualified production statement.

For RNG produced from other low carbon or biogenic feedstocks, such as food and agricultural waste, the RNG producer must develop their own CI calculation and submit it to the DoE following the provisional emissions rate (PER) process defined by the regulation.  To learn more about the PER process, see our blog post here.

If you are a fuels producer who is interested in learning more about 45Z or is looking to pursue the PER process, TRICORD’s compliance experts are here to help.  For inquiries, please contact our low carbon fuels team lead, Hannah Losey P.E., at Hannah.Losey@tricordconsulting.com.