Policy Analysis(政策分析)Life-Cycle Assessment of Biodiesel Production from Microalgae生命周期评估的生物柴油生产藻类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 S I A L V E , J E A N - P H I L I P P E S T E Y E R , AND O L I V I E R BERNARDINRA, UR50 Laboratoire de Biotechnologie de lEnvironnement, 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, FranceReceived March 10, 2009. Revised manuscript received June 8, 2009. Accepted June 18, 2009.LAURENTLARDON，* ELIASARNAUDH，BRUNO SIALVEJEAN - PHILIPPESTEYER，和Olivier 陈智思INRA，UR50 实验室 Biotechnologie DE L环境，AVENUE DES Etangs 酒店，11100 纳博讷，法国，蒙彼利埃 SupAgro，2 地点皮埃尔维亚拉， 34060 Cedex 的蒙彼利埃，法国，科摩罗，INRIA，BP93，索菲亚 - 安提波利斯 06902 Cedex 的法国收稿日期：2009 年 3 月 10 日，修改稿接受日期： 2009 年 6 月 8 日，认证日期：2009 年六月 18 日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本文提供从微藻生产生物柴油的潜在环境影响的分析。微藻产量高，提出了所谓的经济界和科学界的兴趣，但目前还不清楚是否环保有趣的生物柴油的生产和转换步骤需要进一步调整和优化。虚拟设施比较 LCA 研究已开展评估的整个过程链的能量平衡和对环境的潜在影响，从生物质生产生物柴油燃烧。两种不同的培养条件下，名义施肥或氮饥饿，以及两种不同的提取选项，干法或湿法提取，已通过测试。最好的情况已经比第一代生物柴油和石油柴油。该结果证实微藻的电势作为能量来源，但突出的需要，降低能源和肥料消费。因此，文化和优化湿法提取过程中控制氮胁迫似乎是有价值的选择。这项研究还强调，作为一种方式，以减少外部能量的潜力厌氧消化油饼需求和回收的矿物肥料的一部分.1. Introduction(介绍)During the past ten years, fossil fuel depletion and global warming issues have strongly motivated research on fuel production from biomass. Biofuels based on vegetal oil or bioethanol have the key advantage of relying on existing distribution networks and current engine technology. In comparison to oil fuel, biofuel can represent an improvement in terms of emissions of fossil CO2; however, such a technology can also induce negative environmental impacts,caused for instance by pesticides and fertilizers, and can also create a competition for land use with food crops.Therefore the use of first generation biofuel as a sustainable alternative to fossil fuels is questionable and has been the subject of controversy (1). On the other hand, microalgae seem to be an attractive way to produce biofuel due to their ability to accumulate lipids and their very high actual photosynthetic yields; about 3-8% of solar energy can be converted to biomass whereas observed yields for terrestrial plants are about 0.5% (2, 3). These interesting properties lead to potential productivities (in terms of oil production per ha and per year) which are far higher than those of rapeseed or sunflower (4). This high productivity combined with both the moderate competition with feed crop and the possibility to uptake industrial sources ofCO2 has motivated studies depicting microalgae as an alternative source of vegetal oil for biodiesel (2, 4).Despite strong interest from economic and scientific actors, up to now, there is to our knowledge no industrial facility producing biodiesel from microalgae. The studies undertaken on the subject have been restricted to lab and pilot scales. Hence, no thorough Life Cycle Assessment of the production chain from microalgae culture to biodiesel is currently available, with the exception of LCA studies about the cofiring of microalgae with coal (5). The aim of this study is therefore to assess the environmental impacts of this technologically immature process. To do so, we extrapolated laboratory observations combined with known processes developed for first generation biofuel to design a realistic industrial facility. The potential pollution transfers are computed for various scenarios and guide the choice of selected steps in the process chain. In addition to the overall energetic balance of the production chain, the impacts of the combustion of algal biodiesel are compared to those produced by first generation biofuel and diesel fuel.