Carbon Footprint of Oxygenated Gasolines: Case Studies in Latin America, Asia, and Europe

Abstract

Lifecycle analysis was used to estimate well-to-wheel greenhouse gas (GHG) emissions associated with the production, transport, and use of oxygenated gasoline in Colombia, Japan, and France. The study evaluated fuel blends containing ethanol and/or ethyl tertiary-butyl ether (ETBE) that aligned with oxygen and octane specifications currently in place or under consideration for each country. For Colombia, fuel blends meeting a 3.7 wt.% oxygen specification were analyzed using ethanol sourced and produced in the U.S. from corn and in Colombia from sugarcane, and ETBE processed in the U.S. Gulf Coast. For Japan, blends with 1.3, 2.7 and 3.7 wt.% oxygen were analyzed using ethanol sourced and produced in the U.S. and Brazil, and ETBE processed in the U.S. Gulf Coast. For France, oxygenated gasoline blends with 3.7 to 8.0 wt.% oxygen content were analyzed with ethanol produced locally from corn, beet, and wood and imported sugarcane ethanol. Data were populated from both publicly available secondary data sources and new primary data developed for ETBE production in the U.S. and Europe. This study also accounted for distinct lifecycle emissions among gasoline components, focused on aromatic-rich reformate used to boost octane in non-oxygenated fuels. Across each country, results indicate that the replacement of reformate in ethanol-free (E0) gasoline with oxygenates up to 3.7 wt.% oxygen reduces lifecycle GHG emissions by 6–9%, with the highest GHG reduction provided when ETBE alone is used for oxygenate. For higher oxygen blends modeled for France, the highest GHG reduction (19%) was for a blend of 51 vol.% ETBE to achieve 8.0 wt.% oxygen, the equivalent of E23 (gasoline with 23 vol.% ethanol). Overall, displacing ethanol with ETBE to achieve a fixed oxygen level increased GHG benefits relative to ethanol-only blends, owing to the greater volume of the carbon-intensive reformate displaced.