Embrapa Agroenergy – Seven billion inhabitants. This figure marked the year 2011. The life of every human being, like mine or yours, counts as one in this figure. With this number of people on the Planet come to the fore fundamental questions about power, energy supply and sustainability. Thus, the debate over “food production versus energy generation” remains a topic that deserves attention of society and professionals working in research and development of biofuels. For discussion of this issue, the first question to be considered is the fact that the extensive productions of foods require the use of large energy, mainly as a fertilizer and fuel. Nowadays, the fuel is needed to move tractors, combines, trucks, water pumps, and other machinery. Fertilizers are needed to replace the soil nutrients for the plants. The use of heat and electricity are also critical in several agro-industrial processes. For those reasons, it is clear that to produce food for the population is necessary to use energy. On the other hand, there are conflicts and wars vying oil, there is famine in the land and many foods can be processed into fuel. The complexity of the issue increases when considering that the world population is growing, and is estimated to reach 9 billion by 2050. It is also worth that the population of developing countries tends to change the consumption pattern, demanding more food, energy and many other resources. Nations with high population growth, such as China, India and lesser like Brazil follow this same pattern. It is also important to remember phrases of popular knowledge as: “if all countries consumed like the United States, it would require more than one Earth to supply the demand” and that “oil is a finite resource.” In this context is difficult to assess the question about biofuels and food. However, there are data that help us to understand the issue and one of the most important indicator is called “energy balance – EB”, which means the ratio of the amount of useful energy by the energy expended obtain the energy of the specific source. The value of the EB is important to evaluate how much energy is expended to have access to some energy source. It is necessary that this amount to be greater than 1.0, because otherwise it is spending more energy than generated. The EB of ethanol and products of cane sugar is about 7. For ethanol produced from corn, this value is between 1 and 2. Thus, the Brazilian ethanol is placed as biofuels strategy for the national energy matrix, despite the sugar production, even it’s been important as a food or used in food industries. Biofuels can be produced from food or non-food raw materials, called biofuels of first and second generation, respectively. Although there are other definitions for generations fuels related to production processes and the emergence of these processes, the definition related to raw materials is useful for this discussion. The main biofuel produced and sold in Brazil today, ethanol and biodiesel are mainly produced from raw materials for food. In Brazil, almost all the ethanol is produced from cane sugar. Already biodiesel has soybean as the principal raw material, accounting for about 82% of domestic biodiesel production in 2010. Moreover, biofuels can be produced from non-food materials. Today, beef tallow and cottonseed oil are inputs for the production of biodiesel that follow up this line, corresponding about 13% and 2% of Brazilian biodiesel production. Other processes have potential to produce biofuels using biomass: the production process of the cellulosic ethanol, which is the production of ethanol from lignocellulosic biomass by processes of cellulose hydrolysis followed by fermentation, and the process “biomass to liquid” known as BTL, consisting of the biomass gasification followed by Fischer-Tropsch synthesis, which has the potential to generate fuels like gasoline, jet fuel or diesel. Despite much effort in this direction, cellulosic ethanol and BTL are not produced on a large scale, because they have found many technological challenges that preclude its application. However, various efforts are being made in R&D with the purpose of facilitating the industrial production of these fuels. Although there are no prospects for many years or decades these processes will be economically viable. The ethanol of second generation and BTL fuels are possibilities to get it from several lignocellulosic raw materials, including the abundant waste in Agriculture. For sustainable production of these biofuels, it is important that this is done in a context of biorefineries, aiming at maximum utilization of raw materials and energy with the minimal effluent emissions. Conceptually, biorefinery can be understood as “the industrial facility integrating various processes and equipment to convert biomass into fuels, electricity and chemicals from biomass.” These facilities aim to make full use of all biomass streams, minimizing waste volume. The Brazilian sugarcane industry is an example of a biorefinery, because it is produced ethanol, sugar, sugarcane bagasse – used for the generation of bioelectricity – yeast marketed as animal feed and vinasse used as a fertilizer. Finally, it is important to know that steps can be taken to minimize the impact of the growing population on natural resources. From the individual point of view, each of us can try to reduce their consumption pattern, a difficult action nowadays where it is encouraged. Concerning of the science and technology, great effort of scientists, industrialists and policy makers should be made in order to ensure the viability of second generation biofuels and the maximum utilization of raw materials and waste, applying the concept of biorefineries.
Source: Leonardo Valadares, Embrapa Agroenergy Labex