A blend of natural gas liquids (pentanes plus), ethanol, and the biomass-derived co-solvent methyltetrahydrofuran (MeTHF). P-Series fuels are clear, colorless, 89-93 octane, liquid blends that are formulated to be used in flexible fuel vehicles (FFVs). P-Series fuel can be used alone or freely mixed with gasoline in any proportion inside an FFV fuel tank. Currently, P-Series is not being produced in large quantities and is not widely used.  P-Series is the only fuel to be added to the list of authorized alternative fuels under the Energy Policy Act of 1992 (EPAct). It was added to the list through the EPAct petitions provision in 1999.