A life cycle inventory of microalgae-based biofuels production in an industrial plant concept

Microalgae have been reported as a promising alternative for biofuels production. However, the use of microalgae for biofuels is still a challenge due to the intense energy use and the generation of a significant amount of biomass residues in the process. In order to analyze the environmental impacts of different technological processes for the production of biodiesel from microalgae, several studies have been published making use of the Life Cycle Assessment (LCA) methodology, which allows the recognition of the process bottlenecks and supports the identification of alternatives for a more efficient use of the feedstock. Therefore, in this study, a Life Cycle Inventory (LCI) is compiled, based on real pilot-scale process data, which was scaled-up to a microalgae biomass industrial plant for biofuel production. Values of energy, nutrients, water, and materials consumption are used to create an inventory of inputs and outputs for biomass cultivation and biodiesel production, in order to acquire data to conduct a complete LCA modeling in future studies. According to this model, to produce 1 kg of biodiesel it is necessary about 12 kg of dried algae biomass. This study supports the decision-making process in biofuel production to promote the development of sustainable pilot and large-scale algae-based industry, through the identification of critical factors.This work was funded by: project IF/01093/2014/CP1249/CT0003 and research grants IF/01093/2014 and SFRH/BPD/112003/2015 funded by national funds through FCT/MCTES, Portugal, and project UID/EQU/00305/2013 – Center for Innovation in Engineering and Industrial Technology – CIETI. This work was financially supported by: project UID/EQU/00511/2019 – Laboratory for Process Engineering, Environment, Biotechnology and Energy – LEPABE funded by national funds through FCT/MCTES, Portugal (PIDDAC); Project POCI-01- 0145-FEDER-006939 (Laboratory for Process Engineering, Environment, Biotechnology and Energy – LEPABE, UID/EQU/00511/2013) funded by FEDER through COMPETE2020-POCI and by national funds through FCT, Portugal; Project “LEPABE-2-ECO-INNOVATION” – NORTE-01-0145-FEDER-000005, funded by Norte Portugal Regional Operational Program (NORTE 2020), under PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). Authors also acknowledge the “Grupo Interdisciplinario de Biotecnologia Marina (GIBMAR) and “Convenio de Desempeno Ciencia, Tecnologia e Innovacion para la Bioeconomia” from University of Concepcion, Chile, for supporting the experimental data collection at the ´ pilot-plant in Concepcion, Chile, during the Research Visit of M. Branco-Vieira.