Separation (RIN separation event)
The point at which a RIN is detached from its associated gallon under the U.S. Renewable Fuel Standard, allowing the RIN to be traded independently.
Last reviewed: 10 May 2026
Separation under the U.S. Renewable Fuel Standard (RFS) is the regulatory event that detaches a Renewable Identification Number (RIN) from the physical gallon of renewable fuel to which it was originally assigned. After separation, the RIN may be transferred independently of the underlying fuel and can be retired by an obligated party to discharge its Renewable Volume Obligation. The separation framework is codified at 40 CFR 80.1429.
When separation occurs
40 CFR 80.1429 authorizes separation only under specific events. The most common are: blending of the renewable fuel into a transportation fuel that meets the relevant ASTM or other specification; export of the renewable fuel from the U.S.; and certain ownership transfers to a party that is not subject to the RIN-handling restrictions in the regulation. The separation event is reported in the EPA Moderated Transaction System (EMTS) by the party effecting the separation and generates an EMTS event record that updates the RIN status from "assigned" to "separated."
Who may separate a RIN
Generally, the obligated party that blends the renewable fuel with gasoline or diesel — or the exporter that ships the fuel out of the U.S. — is the party authorized to separate the RIN. Pure traders and intermediate marketers who do not blend or export the fuel may not themselves separate RINs. The framework prevents speculative separation that would decouple the RIN from the underlying physical movement.
Why separation matters for pricing
Before separation, RINs trade only as a bundle with the physical fuel — "wet barrel plus assigned RINs." After separation, RINs trade as a financial instrument distinct from any physical gallon. The public weekly volume-weighted average prices on EPA's RIN Trades and Price Information page reflect separated-RIN trades; assigned-RIN volumes are reported separately and trade at a different posture because the buyer is taking physical title to the fuel itself.
Separation in the supply chain
A typical D4 biodiesel supply chain runs: producer reports generation in EMTS; producer sells assigned biodiesel + RINs to a marketer; marketer sells to a blender; blender separates the RINs at the moment of blending (B5/B10/B20 finished fuel into the diesel pool); blender either retains the separated RINs to satisfy its own RVO or transfers them to a third-party obligated party. Each of these steps generates an EMTS event record. The separation step is the moment the RIN becomes a freely-transferable instrument.
Anti-fraud rationale
The separation framework, together with the Quality Assurance Program (QAP) at 40 CFR 80.1467 and the invalid-RIN provisions at 40 CFR 80.1431, is one of three structural anti-fraud pillars in the program. Together they aim to prevent RIN generation without underlying physical fuel. The 2011–2013 invalid-RIN cases (Clean Green Fuel, Absolute Fuels, Green Diesel) tested the original framework; the 2014 QAP rulemaking (79 FR 42078, 18 July 2014) and tightened separation reporting under the same proceeding strengthened it.
Historical context
The separation regime has been substantively unchanged since the 2010 RFS2 final rule (75 FR 14670, 26 March 2010). Recent program updates have refined the EMTS event-reporting cadence and clarified the separation rights of certain export-related transactions, but the underlying structural rule that separation requires blending, export, or qualifying ownership transfer has remained intact.
Special separation rules
A handful of less-common separation pathways are recognised under the regulation. Renewable fuel that is exported from the U.S. carries a mandatory separation event because the obligated party loses the ability to discharge the RVO using a fuel that was never blended into the U.S. transportation pool. Renewable fuel sold to certain non- obligated parties also separates by operation of law. And an obligated party that purchases an assigned-RIN bundle and then blends the fuel itself can separate at the moment of blending — a single-step path common in vertically integrated obligated-party operations.
Sources
EPA RFS regulations: 40 CFR 80.1429 (separation framework), 40 CFR 80.1431 (invalid RIN treatment), 40 CFR 80.1467 (QAP). The 2010 RFS2 final rule is at 75 FR 14670. The 2014 QAP final rule is at 79 FR 42078. Aggregated separated-RIN price data appear on the EPA "RIN Trades and Price Information" page.