The RFS is the regulation in the US mandating the use of renewable fuels (e.g., ethanol and biodiesel) in domestic fuel.

The RFS is adminestered by the EPA which defines the regulations for compliance and sets the annual mandate levels for various classes of renewables.

The RFS uses RINs (renewable identification numbers) to measure and record compliance. RINS are created when renewable fuels are blended into the fuel supply, can be traded once created, and must be submitted to EPA by refiners and importers of fuel to meet their compliance obligation under the RFS.