Biodiesel
Policy Analysis
Life-Cycle Assessment of Biodiesel
Production from Microalgae
´
L A U R E N T L A R D O N , * ,† A R N A U D H E L I A S , †,‡
BRUNO SIALVE,§ JEAN-PHILIPPE STEYER,†
AND OLIVIER BERNARD§
INRA, UR50 Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs,
11100 Narbonne, France, Montpellier SupAgro, 2 Place Pierre
Viala, 34060 Montpellier Cedex 1, France, and Comore, INRIA,
BP93, Sophia-Antipolis Cedex 06902, France
Received March 10, 2009. Revised manuscript received
June 8, 2009. Accepted June 18, 2009.
This paper provides an analysis of the potential environmental impacts of biodiesel production from microalgae. High production yields of microalgae have called forth interest of economic and scientific actors but it is still unclear whether the production of biodiesel is environmentally interesting and which transformation steps need further adjustment and optimization. A comparative LCA study of a virtual facility has been undertaken to assess the energetic balance and the potential environmental impacts of the whole process chain, from the biomass production to the biodiesel combustion. Two different culture conditions, nominal fertilizing or nitrogen starvation, as well as two different extraction options, dry or wet extraction, have been tested. The best scenario has been compared to first generation biodiesel and oil diesel. The outcome confirms the potential of microalgae as an energy source but highlights the imperative necessity of decreasing the energy and fertilizer consumption. Therefore control of nitrogen stress during the culture and optimization of wet extraction seem to be valuable options. This study also emphasizes the potential of anaerobic digestion of oilcakes as a way to reduce external energy demand and to recycle a part of the mineral fertilizers.
1. Introduction
During the past ten years, fossil fuel depletion and global warming issues have strongly motivated research on
Life-Cycle Assessment of Biodiesel
Production from Microalgae
´
L A U R E N T L A R D O N , * ,† A R N A U D H E L I A S , †,‡
BRUNO SIALVE,§ JEAN-PHILIPPE STEYER,†
AND OLIVIER BERNARD§
INRA, UR50 Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs,
11100 Narbonne, France, Montpellier SupAgro, 2 Place Pierre
Viala, 34060 Montpellier Cedex 1, France, and Comore, INRIA,
BP93, Sophia-Antipolis Cedex 06902, France
Received March 10, 2009. Revised manuscript received
June 8, 2009. Accepted June 18, 2009.
This paper provides an analysis of the potential environmental impacts of biodiesel production from microalgae. High production yields of microalgae have called forth interest of economic and scientific actors but it is still unclear whether the production of biodiesel is environmentally interesting and which transformation steps need further adjustment and optimization. A comparative LCA study of a virtual facility has been undertaken to assess the energetic balance and the potential environmental impacts of the whole process chain, from the biomass production to the biodiesel combustion. Two different culture conditions, nominal fertilizing or nitrogen starvation, as well as two different extraction options, dry or wet extraction, have been tested. The best scenario has been compared to first generation biodiesel and oil diesel. The outcome confirms the potential of microalgae as an energy source but highlights the imperative necessity of decreasing the energy and fertilizer consumption. Therefore control of nitrogen stress during the culture and optimization of wet extraction seem to be valuable options. This study also emphasizes the potential of anaerobic digestion of oilcakes as a way to reduce external energy demand and to recycle a part of the mineral fertilizers.
1. Introduction
During the past ten years, fossil fuel depletion and global warming issues have strongly motivated research on
Cited: reduction by replacing fossil fuels. Atmos. Chem. Phys. 2008, 8, 389–395. Report; National Renewable Energy Laboratory, 2001. Enzyme Microb. Technol. 2000, 27, 631–635. Process Intensification 2009, 48, 1146–1151. (10) Oh-Hama, T.; Miyachi, S. In Microalgal Biotechnology; Borowitzka, M. A., Borowitzka, L. J., Eds.; Cambridge University Press: Cambridge, 1988. (11) Chisti, Y. Biodiesel from microalgae. Biotechnol. Adv. 2007, 25, 294–306. programsbiodiesel from algae; National Renewable Energy Laboratory (NREL), 1998. for Mass-Culture of Algae. Biotechnol. Bioeng. 1985, 27, 1572– 1576. (14) Richmond, A. Handbook of Microalgal Culture: Biotechnology and Applied Phycology; Wiley-Blackwell: Oxford, 2003. macro-algae: utility for industrial applications, University of York, 2007. Lett. 2001, 23, 1229–1234. (20) Sazdanoff, N. Modeling and Simulation of the Algae to Biodiesel Fuel Cycle; The Ohio State University, Department of Mechanical Engineering, 2006. Bioresour. Technol. 2009, In Press (doi:10.1016/j.biortech. Technol. 2003, 33, 884–889. in fermenters. J. Biotechnol. 2006, 126, 499–507.