Nest Experience in Life Cycle Assessment (LCA) Research and Development Projects Related with Biofuels and Residues Energy Conversion

NEST experience in Life Cycle Assessment (LCA) research and development projects related with biofuels and residues energy conversion

Mateus Henrique Rocha1, Electo Eduardo Silva Lora1, Marcio Montagnana Vicente Leme1

1NEST – Excellence Group in Thermal Power and Distributed Generation, Institute of Mechanical Engineering, Federal University of Itajubá (UNIFEI), Av. BPS 1303, Itajubá, Minas Gerais State, CEP.: 37500-309 – Brazil

Key words: biofuels, ethanol, biodiesel, municipal solid waste, life cycle assessment, energy conversion

Abstract:

There is an increasing interest in intensifying the production and use of biomass and wastes (residues) to replace fossil fuels for the production of heat, electricity, transportation fuels (biofuels), and various types of chemicals, plastics and other materials (Koçar and Civaş 2013, Limayem and Ricke 2012, Rabelo et al. 2011). The use of biomass, biofuels and wastes (agricultural and municipal) for energy production is encouraged because it can generate profit, contribute to the mitigation of climate change, can help countries diversify their energy sources and achieve energy security, can promote the creation of new options for agriculture and wastes disposal, also including the appeal of new jobs and improved work conditions, all factors that can be associated with food security without any remarkable negative impact on food availability (Castanheira et al. 2014, Nogueira and Capaz 2013). Currently, there is a recent trend to integrate economic, environmental and social aspects in the assessment and optimization of biomass, biofuels and wastes energy conversion supply chains. In regards to the environmental impacts assessment of renewable energy systems the Life Cycle Assessment (LCA) methodology represents an important methodology, to determine quantitatively the environmental impacts comparison of the different types of renewable energy production. The LCA could be used to estimate the positive or negative impacts, in all the stages of the biomass, biofuels and wastes energy recovery utilization life cycles (Carvalho et al. 2014, Chiaramonti and Recchia 2010).

In this sense, the main goal of this presentation is to discuss the major technological changes related to renewable energy production through biofuels and wastes energy conversion. The results presented in this presentation were obtained from the Excellence Group in Thermal Power and Distributed Generation (NEST) from the Federal University of Itajubá (UNIFEI) located in Minas Gerais State in Brazil. Since 2004 NEST/UNIFEI has been carrying out different Research and Developments (R&D) projects related to LCA of biomass and biofuels production and utilization and Municipal Solid Wastes (MSW) energy recovery. A important overview of the programs, projects and technologies related to the use of biofuels in Brazil, as well as, the evaluation of the availability of biomass to electricity generation potential for different industrial and agricultural sectors in Brazil is presented by Lora and Andrade 2009.

Lora et al. 2011 and Escobar et al. 2009 analyzed the main environmental impacts of programs that encourage biofuels production, farmland land requirements and the impacts on food security. The key aim of these studies was to establish what is the level of sustainability of biofuels, through the development of a framework for sustainability indicators as a tool for performance assessment. The most used indicators to measure the biofuels sustainability was indicated as net energy relations, land use utilization and environmental impacts categories. Rocha et al. 2014 carried out a study to evaluate and compare the main environmental life cycle impacts and energy balance (net energy ratio) of ethanol from sugarcane and biodiesel from soybean and palm oil using the LCA tool. A process based on cradle-to-gate attribution LCA method, was applied as the technique to assess the health and environmental impacts of ethanol and biodiesel production systems. The assumed functional unit was 1.0 MJ of energy released by combustion of the analyzed biofuels. The biofuel production systems with higher agricultural yields and extensive use of co-products in its life cycle provided the best environmental results.

In relation to ethanol production currently the technological changes and sustainability concerns of sugarcane ethanol industry is undergoing a huge transition due to recent innovations that could be defined as new paradigms. A detailed description of this trends was included in Lora et al. 2014a and Lora et al. 2014b. The generation and use of co-products in the ethanol production process can grant to the bioenergetics system good indicators in energetic, economic and environmental terms. In ethanol production, it can be observed the generation of bagasse, stillage, filter cake and ashes. The application of the stillage on the sugarcane plantation is influenced by environmental issues and the high cost of fertilizers. In this sense, Rocha et al. 2010 and Rocha et al. 2008 carried out a LCA to evaluate the mass and energy balance of stillage treatment and disposal, showing a fertilizer mass savings of 100% for the potassium, 35% for nitrogen and 20% for phosphorus in the manure, when stillage is applied to 40% of the area of plant and ratoon. In addition, the sugar and alcohol sector has great potential for increasing overall production efficiency in the future by the combined production of ethanol and other biofuels such as methanol from thermochemical pathway through the bagasse gasification for synthesis gas production and subsequent utilization in a Biomass-to-Liquid (BtL) route. Renó et al. 2011 carried out a study to evaluate the environmental impacts of the methanol production from sugarcane bagasse, taking into consideration the balance of the energy life cycle and its net environmental impacts, both are included in a LCA approach. The evaluation was done as a case study of a 100,000 ton/year methanol plant, using sugarcane bagasse as raw material.

Biodiesel, another important biofuel, is also currently the focus of intense research. The use of biodiesel produced from the transesterification of vegetable oils with methanol is currently seen as an interesting alternative to diesel fuel. Yáñez et al. 2009 carried out a study to evaluate the life cycle energy assessment to quantify the total energy flow and assess the overall efficiency of the process of biodiesel production from palm oil in Brazil and Colombia. The authors used the Output/Input energy indicator to analyze the life cycle biodiesel production. The calculated results showed differences between the values attained for the two cases. The Output/Input energy relation for the evaluated cases ranged from 3.8 to 5.7, with an average value of 4.8.

In relation to waste energy recovery, Leme et al. 2014 carried out a study to evaluate the environmental assessment for MSW energy recovery in Brazilian. Four scenarios were designed current situation without any energy recovery, mass burning system in a waste-to-energy facility, landfill biogas utilization in internal combustion engines and landfill biogas utilization in gas turbines, whose environmental behavior were studied applying the LCA approach. The results show the landfill systems as the worst waste management option and that a significant environmental savings is achieved when a wasted energy recovery is done. The best option, which presented the best performance based on considered indicators, is the direct combustion of waste as fuel for electricity generation.

Financial Support: The authors wish to thank the Brazilian National Research and Development Council (CNPq). The Research Support Foundation of the Minas Gerais State (FAPEMIG) and the Coordinating Body for the Improvement of Postgraduate Studies in Higher Education (CAPES) for the funding of Research and Development (R&D) projects. The support of graduate students and the production grants that allowed the accomplishment of the research projects whose results are included in this paper.

References:

Carvalho, A., Mimoso, A.F., Mendes, A.N., Matos, H.A. From a literature review to a framework for environmental process impact assessment index. Journal of Cleaner Production 2014; 64:36–62.

Castanheira, E.G., Grisoli, R., Freire, F., Pecora, V., Coelho, S.T. Environmental sustainability of biodiesel in Brazil. Energy Policy 2014; 65:680–691.

Chiaramonti, D., Recchia, L. Is life cycle assessment (LCA) a suitable method for quantitative CO2 saving estimations? the impact of field input on the LCA results for a pure vegetable oil chain. Biomass and Bioenergy 2010; 34(5):787–797.

Escobar, J.C.P., Lora, E.E.S., Venturini, O.J., Yáñez, E.E., Castillo, E.F., Almazán, O. Biofuels: Environment, technology and food security. Renewable and Sustainable Energy Reviews 2009; 13(6–7):1275–1287.

Koçar, G., Civaş, N. An overview of biofuels from energy crops: Current status and future prospects. Renewable and Sustainable Energy Reviews 2013; 28:900–916.

Leme, M.M.V., Rocha, M.H., Lora, E.E.S., Venturini, O.J., Lopes, B.M., Ferreira, C.H. Techno-economic analysis and environmental impact assessment of energy recovery from Municipal Solid Waste (MSW) in Brazil. Resources Conservation and Recycling 2014; 87:8–20.

Limayem, A., Ricke, S.C. Lignocellulosic biomass for bioethanol production: Current perspectives, potential issues and future prospects. Progress in Energy and Combustion Science 2012; 38(4):449–467.

Lora, E.E.S., Rocha, M.H., Escobar, J.C.P., Venturini, O.J., Renó, M.L.G., Almazán, O. The sugar and alcohol industry in the biofuels and cogeneration era: a paradigm change (part I). Zuckerindustrie (Sugar Industry) 2014a; 139(1):28–36.

Lora, E.E.S., Rocha, M.H., Escobar, J.C.P., Venturini, O.J., Renó, M.L.G., Almazán, O. The sugar and alcohol industry in the biofuels and cogeneration era: a paradigm change (part II). Zuckerindustrie (Sugar Industry) 2014b; 139(2):97–104.

Lora, E.E.S., Escobar, J.C.P., Rocha, M.H., Renó, M.L.G., Venturini, O.J., Almazán, O. Issues to consider, existing tools and constraints in biofuels sustainability assessments. Energy 2011; 36(4):2097–2110.

Lora, E.E.S., Andrade, R.V. Biomass as energy source in Brazil. Renewable and Sustainable Energy Reviews 2009; 13(4):777–788.

Nogueira, L.A.H., Capaz, R.S. Biofuels in Brazil: Evolution, achievements and perspectives on food security. Global Food Security 2013; 2(2):117–125.

Rabelo, S.C., Carrere, H., Maciel Filho, R., Costa, A.C. Production of bioethanol, methane and heat from sugarcane bagasse in a biorefinery concept. Bioresource Technology 201; 102(17):7887–7895.

Renó, M.L.G., Lora, E.E.S., Escobar, J.C.P., Venturini, O.J., Buchgeister, J., Almazán, O. A LCA (life cycle assessment) of the methanol production from sugarcane bagasse. Energy 2011; 36(6):3716–3726.

Rocha, M.H., Capaz, R.S., Lora, E.E.S., Nogueira, L.A.H., Leme, M.M.V., Renó, M.L.G., Almazán, O.O. Life cycle assessment (LCA) for biofuels in Brazilian conditions: A meta-analysis. Renewable and Sustainable Energy Reviews 2014; 37:435–439.

Rocha, M.H., Lora, E.E.S., Venturini, O.J., Escobar, J.C.P., Santos, J.J.C.S., Moura, A.G. Use of the life cycle assessment (LCA) for comparison of the environmental performance of four alternatives for the treatment and disposal of bioethanol stillage. International Sugar Journal 2010; 112(1343):611–622.

Rocha, M.H., Lora, E.E.S., Venturini, O.J. Life Cycle Analysis of different alternatives for the treatment and disposal of ethanol vinasse. Zuckerindustrie (Sugar Industry) 2008; 133(2):88–93.

Yáñez, E.E.A., Lora, E.E.S., Costa, R.E., Torres, E.A. The energy balance in the Palm Oil-Derived Methyl Ester (PME) life cycle for the cases in Brazil and Colombia. Renewable Energy 2009; 34(12):2905–2913.