Integrated environmental assessment of biodiesel production from soybean in Brazil Ota ´vio Cavalett * , Enrique Ortega Laboratory of Ecological Engineering, Food Engineering School, State University of Campinas (UNICAMP), Caixa Postal 6121, CEP 13083-862, Campinas, SP, Brazil article info Article history: Available online 11 September 2009 Keywords: Emergy accounting Embodied energy Material flow accounting Biodiesel abstract This paper presents the results of an environmental impact assessment of biodiesel production from soybean in Brazil. In order to achieve this objective, environmental impact indicators provided by Emergy Accounting (EA), Embodied Energy Analysis (EEA) and Material Flow Accounting (MFA) were used. The results showed that for one liter of biodiesel 8.8 kg of topsoil are lost in erosion, besides the cost of 0.2 kg of fertilizers, about 5.2 m 2 of crop area, 7.33 kg of abiotic materials, 9.0 tons of water and 0.66 kg of air and about 0.86 kg of CO 2 were released. About 0.27 kg of crude oil equivalent is required as inputs to produce one liter of biodiesel, which means an energy return of 2.48 J of biodiesel per Joule of fossil fuel invested. The transformity of biodiesel (3.90E þ 05 seJ J 1 ) is higher than those calculated for fossil fuels as other biofuels, indicating a higher demand for direct and indirect environmental support. Similarly, the biodiesel emergy yield ratio (1.62) indicates that a very low net emergy is delivered to consumers, compared to alternatives. Obtained results show that when crop production and industrial conversion to fuel are supported by fossil fuels in the form of chemicals, goods, and process energy, the fraction of fuel that can actually be considered renewable is very low (around 31%). Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction The use of biofuels has been an increasingly important topic in worldwide discussions on energy resources. In the last decade they have gained wide acceptance among policy makers, scientists, environmentalists, agricultural entrepreneurs and the general public. Usually they are presented as a suitable option for energy supply, considering that if they are adequately supported, they could replace a portion of fossil fuels. The main reasons often presented to promote biodiesel production are: (a) It is a clean or ‘‘green’’ energy produced from renewable natural sources and, therefore, could supply a virtually infinite amount of energy for an infinite period of time; (b) It is often stated that biodiesel, by replacing oil products, would result in the reduction of greenhouse gases’ emissions. It is supposed that the carbon emitted by bio- diesel in the combustion phase is the one absorbed by the plant during its growth through photosynthesis, resulting in a carbon neutral budget; (c) Finally, biodiesel production is presented by the press to be a strategy for rural development. However, when seeking an alternative source of energy, one must evaluate the whole production chain to correctly evaluate potential environmental benefits and disadvantages. If one takes a closer look at the complete biofuels production processes, the benefits are not so clear. In fact, biofuel production requires the use of fossil fuel energy, in the form of fertilizers, agrochemicals, machinery for both agricultural and industrial phases, as well as for transportation of raw materials, inputs and distribution of biofuel for final use. Moreover, depending on the biomass used, biofuels processing could require huge amounts of fossil fuels. The advan- tages in terms of reduction of greenhouse effect and national fossil fuel energy dependency are put into a different perspective, if one takes into account the entire picture and not only the end-of-pipe emissions. In order to do that, many different social and environ- mental factors should be taken into proper account, in addition to the energy yield, the carbon budget and the economic cost. There are several studies in the literature that evaluate one or other environmental aspect of biofuels production [1–6]. However it is necessary to make a comprehensive evaluation to explore different aspects of this debate, underlining the advantages and disadvan- tages of biomass cultivation to produce energy [7,8]. In order to obtain such a wider overview on the environ- mental impacts of the biodiesel production process in Brazil, a comprehensive assessment based on the parallel use of different evaluation methods was carried out. Soybean is the most important feedstock used to produce biodiesel in Brazil, where approximately 90% of biodiesel is produced from * Corresponding author. Tel.: þ55 19 35214058; fax: þ55 19 35211513. E-mail address: otaviocav@gmail.com (O. Cavalett). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro 0959-6526/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.jclepro.2009.09.008 Journal of Cleaner Production 18 (2010) 55–70