Life cycle assessment of biofuels

Sustainable bioenergy production is a key issue in the global effort to mitigate greenhouse gas (GHG) emissions and climate change effects. A holistic investigation of the biofuel supply chain and production routes is required to realize sustainable processes. This analysis should consider technical, economic, and environmental issues regarding the production of raw biomass, application of conversion technologies, and distribution and use of products. Although technical and economic aspects can be quantified by well-established physical and financial methods, the quantification of environmental impacts is a complex task owing to the range of environmental aspects and methodologies for their analysis. Life cycle assessment (LCA), a technique introduced in the 1960s and established since the 1990s, provides a comprehensive methodology for quantification of the environmental impacts of processes, including biofuel production, and can be used as a reliable decision-making tool.

The goal of this chapter is to present the key issues of LCA of biofuel production. Section 2.1 focuses on the main challenges of sustainable biofuel production and addresses the key issues regarding environmental performance in this area. Section 2.2 introduces the methodological framework of LCA and highlights its role in the promotion of biofuels. It also presents the key issues that should be considered when conducting an LCA of a biofuel production system and discusses the importance of each step of the complete biofuel life cycle, including raw material production and extraction, processing, transportation, manufacturing, storage, distribution, and utilization. Section 2.3 presents important sustainability aspects of major biomass-to-biofuel conversion routes, including first-, second-, third-, and fourth-generation biofuels. Section 2.4 provides an overview of recent LCA studies in the field of biofuel production, the main assumptions applied in these studies, and the challenges raised during the investigation of alternative biofuel production systems.