D4 RIN

A D4 RIN is a Renewable Identification Number assigned to a gallon of qualifying biomass-based diesel produced or imported into the United States under the federal Renewable Fuel Standard (RFS). The RIN serves as the unit of compliance: refiners and importers of petroleum-based gasoline and diesel are obligated parties under the program, and they discharge their annual Renewable Volume Obligation (RVO) by acquiring and retiring RINs that match the categories EPA sets each year.

Where D4 sits in the program

The RFS is structured as four nested categories of renewable fuel: D6 (conventional renewable fuel, primarily corn-starch ethanol), D5 (advanced biofuel other than biomass-based diesel and cellulosic), D4 (biomass-based diesel) and D3 (cellulosic). D4 is the biomass-based diesel category, which in practice means biodiesel (FAME) and renewable diesel (also called hydrotreated vegetable oil, HVO, or non-ester renewable diesel, NERD) made from feedstocks such as soybean oil, used cooking oil, distillers corn oil, canola oil, tallow, and white grease.

Equivalence values

A D4 RIN represents one ethanol-equivalent gallon. Because biomass-based diesel has a higher energy content than ethanol, EPA assigns equivalence values (EVs) under 40 CFR 80.1415 that determine how many RINs each physical gallon generates:

• FAME biodiesel — 1.5 RINs per gallon — 40 CFR 80.1415(b)(2)
• Renewable diesel (default) — 1.7 RINs per gallon — 40 CFR 80.1415(b)(4)
• Renewable diesel (facility-specific, ~11% of the D4 pool) — 1.6 RINs per gallon — 40 CFR 80.1415(c)

The EV regime changes on 1 January 2027: under the existing rule, non-ester EVs drop to 1.5 from that date forward, aligning the RIN yield of renewable diesel with that of FAME biodiesel. Modeling and chart annotation of D4 generation must treat 2027 as a regime boundary.

D4 generation and EMTS

When a producer or importer reports a qualifying batch in the EPA Moderated Transaction System (EMTS), RINs are generated and assigned to the producer's account. Each RIN carries a 38-character identifier that includes the generation year (vintage), the company ID, the batch number, and the EV multiplier embedded in the assignment record. RINs may be transferred to obligated parties or to non-obligated participants, and they remain "assigned" to a fuel volume until that volume is sold to a downstream party that separates the RIN from the gallon. After separation, the RIN moves freely until retirement.

Vintage rules and carryover

D4 RINs are valid for the calendar year of generation and the immediately following compliance year, subject to a 20% rollover cap on the use of prior-year RINs against current-year obligations under 40 CFR 80.1427. Two-year vintage windows mean that a 2025-vintage D4 RIN can satisfy 2025 or 2026 obligations and is then expired.

Pricing and historical drivers

The D4 weekly volume-weighted average price published by EPA's RIN Trades and Price Information page reflects transactions reported to EMTS. Historical price levels have responded to documented program changes including the Renewable Volume Obligation rule cycles, the lapse and reinstatement of the Biodiesel Blender's Tax Credit (BTC), the 2017–2019 small-refiner exemption (SRE) wave, the 2020 demand contraction associated with COVID-19, the post-2022 expansion of renewable diesel capacity, and the July 2025 OBBBA (One Big Beautiful Bill Act) provisions affecting the related Section 45Z Clean Fuel Production Credit. D4 prices are also referenced in the soybean-oil/heating-oil (BOHO) margin proxy used by FAME biodiesel producers.

Sources

EPA Renewable Fuel Standard regulations are codified at 40 CFR Part 80, Subpart M, with EVs at 40 CFR 80.1415, generation rules at 40 CFR 80.1426, and separation rules at 40 CFR 80.1473. Annual RVO determinations and the "Set" rules are published in the Federal Register; recent multi-year volumes were finalized in the EPA RFS Set Rule (Federal Register vol. 88, 27 July 2023). Aggregated RIN price and volume data are published weekly on the EPA "RIN Trades and Price Information" page.