Main Characteristics of LCA

Life cycle assessment (LCA) has a number of defining characteristics that enables it to address questions that no other assessment tools can address. This chapter begins by demonstrating how the use of LCA in the late 2000s led to a drastic shift in the dominant perception that biofuels were “green”, “sustainable” or “carbon neutral”, which led to a change in biofuel policies. This is followed by a grouping of the LCA characteristics into four headlines and an explanation of these: (1) takes a life cycle perspective, (2) covers a broad range of environmental issues, (3) is quantitative, (4) is based on science. From the insights of the LCA characteristics we then consider the strengths and limitations of LCA and end the chapter by listing 10 questions that LCA can answer and 3 that it cannot. Learning objectives After studying this chapter the reader should be able to: • Explain the relevance of LCA as a tool for environmental management. • Explain four main characteristics of LCA. • Demonstrate an understanding of strengths and limitations of LCA by providing examples of environment-related questions that LCA can answer and questions that LCA cannot answer. A. Bjørn M. Owsianiak C. Molin A. Laurent Division for Quantitative Sustainability Assessment, Department of Management Engineering, Technical University of Denmark, Kongens Lyngby, Denmark A. Bjørn (&) C. Molin A. Laurent CIRAIG, Polytechnique Montréal, 3333 Chemin Queen-Mary, Montréal, QC, Canada e-mail: [email protected] © Springer International Publishing AG 2018 M.Z. Hauschild et al. (eds.), Life Cycle Assessment, DOI 10.1007/978-3-319-56475-3_2 9 2.1 Why Is LCA Important? Biofuel Case LCA has a number of defining characteristics. Before elaborating on these characteristics a real life case is presented to show how the use of LCA provided new insights and led to major changes in policy. This is the case of first generation biofuels used in the transport sector. The use of biofuels is not a new trend. They were used in the form of wood and peat before the industrialisation and were pretty much the only source of fuels then. This changed with the emergence of cheap fossil fuels, first in the form of coal, later followed by oil and natural gas. By the end of the twentieth-century fossil fuels had become the dominating source for meeting the world’s primary energy demand. At the same time the transportation sector of developed nations was responsible for an increasing share of the total national energy demands [e.g. EC (2012)]. While electricity and heat increasingly were supplied by other sources than fossil fuels, a similar transition could not be observed for transportation energy (IEA 2015). The 2000s witnessed a renewed interest in using biofuels in the transportation sector, spurred by increasing oil prices, the question of energy security and concerns over climate change. Biofuels were seen as potentially cost competitive with gasoline and diesel and they were considered means to reduce dependencies on large exporters of oil, many of which were (and are) located in politically unstable regions of the world. In the early 2000s biofuels in the transportation sector were also generally considered much better for the climate than fossil fuels. The reasoning was that the CO2 emitted from the combustion of biofuels has a “neutral” effect on climate change, because it belongs to the biogenic carbon cycle, meaning that it used to be in the atmosphere before being taken up, via photosynthesis, by the plants that were the sources of the biofuel and that it will be taken up by new plants again. By contrast, CO2 emitted from the combustion of fossil fuels originates in carbon that belongs to the much slower geological carbon cycle and can be considered as effectively isolated from the atmosphere, because it would have stayed in the ground for millions of years, had it not been extracted to be used as fuel. While the distinction between biogenic and fossil CO2 is important, LCA studies (Zah and Laurance 2008; Fargione et al. 2008; Searchinger et al. 2008) have shown that it was a mistake to: (1) consider the use of biofuels in the transport sector inherently “climate neutral” (2) disregard potential increases in environmental problems other than climate change from a transition from fossil fuels to biofuels. Regarding the first point, LCA takes a life cycle perspective when evaluating environmental impacts of a product or a system. In this case it means not only considering the use stage of the biofuel, i.e. where its chemical energy is transformed to kinetic energy in a vehicle’s combustion engine, but also considering the industrial and agricultural processes prior to the delivery of the biofuel to the fuel tank of the vehicle (see Fig. 2.1). 10 A. Bjørn et al.