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This work presents the first comprehensive assessment of ethanol dissolved in rainwater of Sao Paulo State's sugar cane belt, considering the period from 2012 to 2017. Ethanol concentrations ranged from 0.25 to 20.9 μmol L−1, with a volume-weighted mean (VWM) of 4.67 ± 0.13 μmol L−1 (n = 410). Despite the increasing use of ethanol fuel in Brazil, during the study period, the ethanol concentration in rainwater showed an average decrease of 0.54 μmol L−1 per year, attributed to technological improvements in vehicular fuel combustion and catalysts. Anthropogenic emissions appeared to overwhelm possible seasonal fluctuations of ethanol in rainwater due to biogenic sources or meteorological conditions such as temperature, solar radiation, rainfall amount, rainfall rate, and air mass origin. Higher VWM concentrations were generally observed in dry months, when the production of ethanol in the distilleries was highest and biomass burning increased. Consideration of ethanol oxidation in aqueous media by OH radicals indicated that secondary formation of highly toxic aldehydes is likely to increase with greater use of this biofuel. Dissolution of gaseous ethanol during cloud formation appeared to be a more important mechanism of atmospheric removal of this alcohol, compared to below-cloud processes. The wet flux of ethanol was ca. 3 kg ha−1 year−1 and there were evidences that atmospheric replenishment of this species was fast. Brazil has used ethanol fuel on a large scale since the 1980s, so better understanding of the behavior of this species in the lower troposphere of the study region can provide valuable information to assist in predicting future worldwide impacts of increasing use of this biofuel.

This paper addresses the dynamic sociotechnical construction of automotive-energy infrastructures, based on the case of ethanol fuel in Brazil in the 20th and early 21st centuries. Energy infrastructure projects are afforded but also constrained by technical and institutional “residues” of previous initiatives and achievements. The notion of “knots” is introduced to explore how sociotechnical entanglements interlinking elements from distinct levels of the societal fabric become stabilized and shape subsequent developments. This extension of the sociotechnical approach is shown to be fruitful to better understand the embedding of ethanol fuel in the process of evolution of the automotive-energy infrastructure in Brazil during the 20th century. This then offers building blocks for analysis and design of energy infrastructures in general.

The paper describes and analyses: the events, motivations, policies and forces that led to the introduction of ethanol as fuel in Brazil; the recent decision to continue with the programme; and draws important lessons that might be relevant for other regions and countries as they contemplate a transition away from petroleum transportation fuels. The alcohol programme began in the late 1970s; by 1986, as a result of large subsidies, 76% of all new cars were built to be fuelled by alcohol, but by 1996 that was down to less than 1%. It is shown that the pursuit of ethanol fuel in Brazil was not based on long term plans with deep-set values, but has been an ad hoc response to a particular set of circumstances, including a depressed sugar industry, an ambitious attempt to reduce oil dependence and more recently a range of 'green' arguments.

This paper analyzes the product life cycle of the production of sugar cane for ethanol fuel in Brazil, to determine its sustainability in the long term. I have used a case study methodology and qualitative analysis to break down important elements involved in the production of sugar cane ethanol in Brazil. These elements include renewable energy aspects, agricultural practices, and the consequences of production on society involved in the process. Brazil currently derives 46 percent of its energy from renewable sources, but it is questionable whether they are sustainable in the long run. In order to create this renewable source of energy, the conversion process involves manually burning sugar cane, and creates harmful emissions. The industrialization process of planting and harvesting sugar cane has increased the use of chemical and technology, having a profoundly negative impact on the ecosystem due to the chemical contamination of the waterways, genetic impoverishment, and soil erosion. In addition, workers are exploited, poverty has been exacerbated, and food prices have increased. Although the production of ethanol has many advantages, including the substitution of petroleum, the social consequences remain a matter of grave concern. The process of obtaining renewable energy includes ecological destruction and negative social effects that are externalities of the economic calculations, and the requirements of capital accumulation dominate decision-making.

Currently, many scientists worldwide are studying the recycling or reuse of waste materials to make useful products. For example, silicate-based wastes have been studied for use as raw material in the ceramic industry. Although numerous types of waste have been studied, sugarcane bagasse ash (SCBA) has been overlooked, probably because this type of residue is more common in developing countries that produce sugar and alcohol from sugarcane. Bagasse is a by-product of the cane sugar industry. Brazil is the world’s largest producer of alcohol and sugar from sugarcane and has an extensive alternative program for automobile fuel. The new technology of flex-fuel (alcohol/gasoline) vehicles, developed in the 1990s and applied to new cars in 2003 revived the Brazilian PROALCOOL program. Today, several million flex-fuel cars are in use, and more than 85% of the new cars produced in the country run on this system (ProAlcool 2011; History of ethanol fuel in Brazil 2011; Goldemberg 2008). In the production of sugar and alcohol, sugarcane is ground and the resulting juice is extracted to obtain sugar or used in a fermentation process to produce alcohol. The fibrous matter that remains after sugarcane has been crushed to extract the juice is called bagasse (or “bagaco,” in Portuguese). There are many applications and much research effort is directed at exploring the potential of bagasse as a renewable power generation source, for the production of bio-based materials (for example, bioethanol and briquettes or pellets), cattle feed, building materials, etc. Basically, bagasse is a fibrous material containing cellulose (~50%), hemicellulose and lignin as the major (~95%) compounds. There are also waxes, inorganic materials and/or salts inside the plant tissues that will result in the final ash (oxides and carbonates) after firing (Pandey et al. 2000). Although there is a great deal of research in Brazil on sugarcane bagasse briquetting, showing the many advantages of using briquettes instead of bagasse, factories still burn bagasse. Currently, sugarcane bagasse is used as a primary fuel source in sugar mills. It is burned in a boiler to produce steam which is utilized in the factory’s processes and also to power turbines for the production of electrical energy. Today, the cogeneration of electricity by sugar and alcohol mills accounts for ca. 5% of the total electricity produced in Brazil