Producing technological equipments (at large scale) that make our daily lives easier or traveling long distances in a short time were made possible due to the use of petroleum derivates. Together they represent 55% of the world’s energy consumption.
Unfortunately, the availability of these materials will be shorter in the next decades and their extraction, more complex. In addition to these problems, there are the greenhouse gas emissions (GEE) to the atmosphere, produced by the burning of these fossil fuels.
These facts raise the following question: what source of renewable energy holds energetic efficiency similar to petroleum but does not have its deficiencies? This can be a complex issue for some countries. For Brazil, the answer is easy as we have sugarcane bioethanol.
Ethanol is an oxygenated organic compound with chemical formula C2H5OH. It is used in our country as an automobile fuel in two versions: hydrous alcohol (in alcohol powered cars or flex fuel) and anhydrous alcohol (added to gasoline at a proportion of 25%). The first type has up to 7% of water in the mixture, whilst the second has a maximum of 0.7%.
In Brazil, we produce ethanol through sugarcane juice fermentation, via the action of yeast of the Saccharomyces cerevisiae species. Corn (USA and China), sugar beet (European Union), cassava, and wheat are used as raw material in other countries.
The majority of these plants, however, have a disadvantage when compared to sugarcane. To produce ethanol from them, it is first necessary to transform the starch into sugar and then ferment it into ethanol. This additional stage reduces the yield of the process and increases production costs. For example, whilst USA spends 1 unit of equivalent fossil fuel energy to generate 1.3 ethanol units, in Brazil, the same unit produces between 8 and 9 sugarcane ethanol units.
Allied to energy efficiency there are environmental aspects. Analyses made by Isaías Macedo, a mechanical engineer from Unicamp, show that the substitution of gasoline by ethanol would lead to a reduction in the total GEE emissions of about 2,6t CO2eq./m3 (anhydrous ethanol) and 1,7t CO2eq./m3 (hydrous ethanol). This indicates the superiority of sugarcane ethanol compared to other technologies that produce the biofuel, regarding the relationship of obtained renewable energy / fossil energy used.
To the arguments presented in favor of Brazilian ethanol, we can add the increase in the world’s demand for energy in the last decades. This encouraged industrialized and emerging countries to begin a series of research activities on new energy sources, especially renewable ones. Sugarcane bioethanol again comes out ahead, as it is produced from a low cost raw material and uses a well-known and established state-of-the-art technology. Ways to industrially utilize the integral sugarcane biomass (and not only the juice) need to be studied now.
However, a series of obstacles have to be overcome in this process. These challenges are the main focuses of CTBE’s research.