E85

E85 is a motor fuel blend consisting primarily of ethanol and gasoline, with up to 85% ethanol by volume and up to 15% gasoline. The ethanol is typically derived from plant materials such as corn in North America or sugarcane in Brazil. Because the exact ethanol content can vary by season, region, and local regulations, E85 blends in practice are commonly described as ranging from about 70% to 85% ethanol.

Flexible-fuel vehicles are designed to run on gasoline, E85, or any mixture in between. Vehicles equipped with flexible-fuel technology adjust the air-fuel mixture and ignition timing automatically based on the ethanol content detected or estimated by the engine control unit. These vehicles use ethanol-compatible materials and seals to tolerate ethanol’s properties, such as its solvent effects and tendency to absorb water.

E85 typically has a higher octane rating than many conventional gasoline blends, allowing higher compression in specially tuned engines. However, ethanol contains less energy per gallon than gasoline, so fuel economy in miles per gallon is generally lower when running on E85. The exact difference depends on the vehicle and driving conditions, but reductions of roughly 15–30% in mpg are common compared with pure gasoline.

Environmental considerations for E85 depend on feedstock and farming practices. Ethanol can reduce certain pollutants and greenhouse gas emissions relative to gasoline, but lifecycle and land-use factors influence overall benefit. Availability of E85 varies by country and region, with a larger network of fueling stations in some markets.