Definitions, Sources and Explanatory Notes

 Category:   Petroleum Refining & Processing
 Topic:   Oxygenate Production


Key Terms Definition
Barrel A unit of volume equal to 42 U.S. gallons.
Captive Refinery Oxygenate Plants Oxygenate production facilities located within or adjacent to a refinery complex.
Fuel Ethanol An anhydrous denatured aliphatic alcohol intended for gasoline blending as described in Oxygenates definition.
Gasohol A blend of finished motor gasoline containing alcohol (generally ethanol but sometimes methanol) at a concentration of 10 percent or less by volume. Data on gasohol that has at least 2.7 percent oxygen, by weight, and is intended for sale inside carbon monoxide nonattainment areas are included in data on oxygenated gasoline.
Merchant Oxygenate Plants Oxygenate production facilities that are not associated with a petroleum refinery. Production from these facilities is sold under contract or on the spot market to refiners or other gasoline blenders.
MTBE (Methyl tertiary butyl ether) An ether intended for gasoline blending as described in "Oxygenates."
Oxygenates Substances which, when added to gasoline, increase the amount of oxygen in that gasoline blend. Ethanol, Methyl Tertiary Butyl Ether (MTBE), Ethyl Tertiary Butyl Ether (ETBE), and methanol are common oxygenates.
  • Fuel Ethanol: Blends of up to 10 percent by volume anhydrous ethanol (200 proof) (commonly referred to as the "gasohol waiver").
  • Methanol: Blends of methanol and gasoline-grade tertiary butyl alcohol (GTBA) such that the total oxygen content does not exceed 3.5 percent by weight and the ratio of methanol to GTBA is less than or equal to 1. It is also specified that this blended fuel must meet ASTM volatility specifications (commonly referred to as the "ARCO" waiver).
    Blends of up to 5.0 percent by volume methanol with a minimum of 2.5 percent by volume cosolvent alcohols having a carbon number of 4 or less (i.e., ethanol, propanol, butanol, and/or GTBA). The total oxygen must not exceed 3.7 percent by weight, and the blend must meet ASTM volatility specifications as well as phase separation and alcohol purity specifications (commonly referred to as the "DuPont" waiver).
  • MTBE (Methyl tertiary butyl ether): Blends up to 15.0 percent by volume MTBE which must meet the ASTM D4814 specifications. Blenders must take precautions that the blends are not used as base gasolines for other oxygenated blends (commonly referred to as the "Sun" waiver).
  • Petroleum Administration for Defense (PAD) Districts Geographic aggregations of the 50 States and the District of Columbia into five districts by the Petroleum Administration for Defense in 1950. These districts were originally defined during World War II for purposes of administering oil allocation. Description and maps of PAD Districts and Refining Districts.

    For definitions of related energy terms, refer to the EIA Energy Glossary.


    Fuel Ethanol Production:
  • 1981-1991: Fuel ethanol production is equal to fuel ethanol consumption (see source information for "Consumption" below).
  • 1993-2004: Calculated as fuel ethanol consumption plus fuel ethanol stock change minus fuel ethanol net imports. These data differ slightly from the original production data from Energy Information Administration (EIA), Form EIA-819M, "Monthly Oxygenates Telephone Report," and predecessor form, which were not reconciled and updated to be consistent with the final balance.
  • 1992, 2005 forward: EIA, Form EIA-819M, "Monthly Oxygenates Telephone Report."

  • Consumption (used to estimate fuel ethanol production for 1981-2004):
  • 1981-1989: EIA, Estimates of U.S. Biofuels Consumption 1990, Table 10; and EIA, Office of Coal, Nuclear, Electric and Alternate Fuels (CNEAF), estimates.
  • 1990-1992: EIA, Estimates of U.S. Biomass Energy Consumption 1992, Table D2; and EIA, CNEAF, estimates.
  • 1993-2004: EIA, Petroleum Supply Annual, Tables 2 and 16. Calculated as ten percent of oxygenated finished motor gasoline field production (Table 2), plus fuel ethanol refinery input (Table 16).

  • MTBE:
  • Energy Information Administration, Form EIA-819M, "Monthly Oxygenates Telephone Report".

  • EIA Forms & Instructions .
  • Background, Survey Methodology and Statistical Details .

  •   Explanatory Notes

  • Oxygenate production is reported by all facilities that produce oxygenates.
  • Description and maps of PAD Districts and Refining Districts from the Petroleum Supply Monthly.