The use of biofuels in Brazil

The use of ethanol as a vehicle fuel in Brazil is extensive and has a long history. Brazil is the country that consumes more biofuels in the transportation sector: hydrous ethanol in flex-fuel vehicles, anhydrous ethanol mixed with gasoline (from 20 to 27% by volume) and biodiesel mixed with diesel oil (7% by volume). In 2015, the amount of biofuels in the transportation sector reached 20.7% (by energy). This is far beyond other countries.

Energy Source Transportation

Although the widespread use of ethanol fuel in the 70’s had been driven by macro-economic issues (balance of foreign trade of the country), its environmental benefits were identified early: a renewable product, with less formation of pollutants during combustion due to its oxygenated molecule, as well as reduced emissions of greenhouse gases.

When ethanol engines were launched, they had clear environmental advantage over gasoline engines, by emitting less CO, HC and NOx (in the 80's and 90’s). With the widespread use of three-way catalysts since 1998, however, this is no longer true: the emissions released to the atmosphere after the treatment given by the catalyst are roughly equal, regardless of the fuel used (gasoline, ethanol, or natural gas). Thus, the current importance of the use of biofuels in internal combustion engines lay primarily on the issue of reduction of greenhouse gases, especially CO2.

The future of ethanol as a fuel relies on technological advances in all stages of its industrial chain, from the agricultural phase up to their consumption in internal combustion engines. For ethanol to remain competitive as a substitute for gasoline, it is essential that its environmental, technical and economic advantages are preserved in the face of technological advances that have been introduced in engines that use fossil fuels. As an example, the advances obtained in the technology of plu-in hybrid gasoline vehicles with high efficiency (and therefore low CO2 emissions) could threaten the competitiveness of biofuels in reducing greenhouse gases.

Since 2003, Brazil has seen a huge growth in the production of flex-fuel vehicles - that is, vehicles capable of using Brazilian gasoline (20 to 27% ethanol) or hydrated ethanol - as shown in Figure below.

Production: Passenger cars

However, flex-fuel engines cannot be optimized for either ethanol or gasoline: they are a compromise solution that, as indicated in the name itself, enables the consumers to choose the fuel that seems most convenient to them. Engines dedicated to the use of ethanol can be optimized to explore the characteristics of this biofuel: higher octane number, higher burning rate, and higher latent heat of vaporization. Since the beginning of the production of flex-fuel vehicles, the automakers have suspended the development of engines dedicated to ethanol.