Mateus F. Chagas

Comparative LCA of ethanol versus gasoline in Brazil using different LCIA methods

PurposeThe main objective of this study is to expand the discussion about how, and to what extent, the environmental performance is affected by the use of different life cycle impact assessment (LCIA) illustrated by the case study of the comparison between environmental impacts of gasoline and ethanol form sugarcane in Brazil.MethodsThe following LCIA methods have been considered in the evaluation: CML 2001, Impact 2002+, EDIP 2003, Eco-indicator 99, TRACI 2, ReCiPe, and Ecological Scarcity 2006. Energy allocation was used to split the environmental burdens between ethanol and surplus electricity generated at the sugarcane mill. The phases of feedstock and (bio)fuel production, distribution, and use are included in system boundaries.Results and discussionAt the midpoint level, comparison of different LCIA methods showed that ethanol presents lower impacts than gasoline in important categories such as global warming, fossil depletion, and ozone layer depletion. However, ethanol presents higher impacts in acidification, eutrophication, photochemical oxidation, and agricultural land use categories. Regarding to single-score indicators, ethanol presented better performance than gasoline using ReCiPe Endpoint LCIA method. Using IMPACT 2002+, Eco-indicator 99, and Ecological Scarcity 2006, higher scores are verified for ethanol, mainly due to the impacts related to particulate emissions and land use impacts.ConclusionsAlthough there is a relative agreement on the results regarding equivalent environmental impact categories using different LCIA methods at midpoint level, when single-score indicators are considered, use of different LCIA methods lead to different conclusions. Single-score results also limit the interpretability at endpoint level, as a consequence of small contributions of relevant environmental impact categories weighted in a single-score indicator.

Technical and economic assessment of trash recovery in the sugarcane bioenergy production system

Mechanized sugarcane (Saccharum spp.) harvest without burning has been increasingly adopted in Brazil, increasing trash availability on the field. This study aims at showing the importance of using an integrated framework tool to assess technical and economic impacts of integral harvesting and baling trash recovery strategies and different recovery rates as well as its implications in the sugarcane production, transport and processing stages. Trash recovery using baling system presents higher costs per unit of mass of recovered trash in comparison to system in which trash is harvested and transported with sugarcane stalks (integral harvesting system). However, the integrated agricultural and industrial assessment showed that recovering trash using baling system presents better economic results (higher internal rate of return and lower ethanol production cost) than the integral harvesting system for trash recovery rates higher than 30 %. Varying trash recovery fraction, stalks productivity and mean transport distance for both integral harvesting and baling systems, sensitivity analyses showed that higher trash recovery fractions associated with higher stalks yields and long transport distances favors baling system, mainly due to the reduction of bulk load density for integral harvesting system under those conditions.

Hybrid Input-Output Life Cycle Assessment of First- and Second-Generation Ethanol Production Technologies in Brazil

A hybrid approach combining life cycle assessment and input‐output analysis was used to demonstrate the economic and environmental benefits of current and future improvements in agricultural and industrial technologies for ethanol production in Brazilian biorefineries. In this article, three main scenarios were evaluated: first‐generation ethanol production with the average current technology; the improved current technology; and the integration of improved first‐ and second‐generation ethanol production. For the improved first‐generation scenario, a US

Techno-economic analysis and climate change impacts of sugarcane biorefineries considering different time horizons

1 million increase in ethanol demand can give rise to US

Sustainability Assessment Methodologies

2.5 million of total economic activity in the Brazilian economy when direct and indirect purchases of inputs are considered. This value is slightly higher than the economic activity (US

Use of VSB to Plan Research Programs and Public Policies

1.8 million) for an energy equivalent amount of gasoline. The integration of first‐ and second‐generation technologies significantly reduces the total greenhouse gas emissions of ethanol production: 14.6 versus 86.4 grams of carbon dioxide equivalent per megajoule (g CO‐eq/MJ) for gasoline. Moreover, emissions of ethanol can be negative (–10.5 g CO‐eq/MJ) when the system boundary is expanded to account for surplus bioelectricity by displacement of natural gas thermal electricity generation considering electricity produced in first‐generation optimized biorefineries.

The Agricultural Production Model

BackgroundEthanol production from lignocellulosic feedstocks (also known as 2nd generation or 2G ethanol process) presents a great potential for reducing both ethanol production costs and climate change impacts since agricultural residues and dedicated energy crops are used as feedstock. This study aimed at the quantification of the economic and environmental impacts considering the current and future scenarios of sugarcane biorefineries taking into account not only the improvements of the industrial process but also of biomass production systems. Technology assumptions and scenarios setup were supported by main companies and stakeholders, involved in the lignocellulosic ethanol production chain from Brazil and abroad. For instance, scenarios considered higher efficiencies and lower residence times for pretreatment, enzymatic hydrolysis, and fermentation (including pentoses fermentation); higher sugarcane yields; and introduction of energy cane (a high fiber variety of cane).ResultsEthanol production costs were estimated for different time horizons. In the short term, 2G ethanol presents higher costs compared to 1st generation (1G) ethanol. However, in the long term, 2G ethanol is more competitive, presenting remarkable lower production cost than 1G ethanol, even considering some uncertainties regarding technology and market aspects. In addition, environmental assessment showed that both 1G (in the medium and long term) and 2G ethanol can reduce climate change impacts by more than 80% when compared to gasoline.ConclusionsThis work showed the great potential of 2G ethanol production in terms of economic and environmental aspects. These results can support new research programs and public policies designed to stimulate both production and consumption of 2G ethanol in Brazil, accelerating the path along the learning curve. Some examples of mechanisms include: incentives to the establishment of local equipment and enzyme suppliers; and specific funding programs for the development and use of energy cane.

Use of the VSB to Assess Biorefinery Strategies

This chapter presents some of the most useful techniques applied in the VSB to support both the sustainability assessment and decision making regarding many products and process based on biomass, especially those using sugarcane as feedstock.

Biorefinery Products Logistics, Commercialization, and Use

The VSB comprises a useful framework for assessing research programs, and define and evaluate the effects of public policies. This chapter describes two cases regarding the use of VSB for R&D evaluation—enzyme development and use of energy cane as a new feedstock for sugarcane biorefinery—and a public policy formulation for biogas production and use in the biorefinery context.

Life cycle assessment of butanol production in sugarcane biorefineries in Brazil.

Numerous crops have been used to produce bioenergy around the world. Among the alternatives of biomass intended for renewable energy purposes, sugarcane is highlighted as a great alternative, and the knowledge of all the steps of the agricultural phase of its production chain is imperative in order to improve the sustainability of bioethanol production in Brazil. This chapter presents an agricultural model, called CanaSoft, which is intended for simulation and assessment of the most important agricultural parameters of biomass production system alternatives, as well as for integrated sustainability optimization. The complete description of the parameters considered in the model for sugarcane production is provided, as well as a description of its adaptation to other biomass.