3 Life cycle assessment

3 Life cycle assessment of biofuels: methods and tools 3.1 Life cycle assessment – an overview Life cycle assessment (LCA) is an environmental assessment methodology which analyses all resource requirements (energy, water, etc.) and material flows (inputs and outputs, co-products, emissions, etc.) of a product system. Fields of application are product development and improvement, strategic planning, marketing and public policy making. LCA is one of several environmental management techniques. It typically does not address the economic or social aspects of a product. Generally, the information obtained from an LCA should be used as part of a much more comprehensive decision process or used to understand the broad or general trade-offs involved. Comparing the results of different LCA studies is only possible if the assumptions and context of each study are the same. In addition to an LCA, in this project a socio-economic and political analysis has also been carried out. LCA is performed according to the principle summarised by the expression “from cradle to grave”, i. e. all previous stages of the input production up to the extraction of the natural resources on the one hand and all subsequent stages of an output after it goes out of the system on the other hand are included. The calculated results are expressed in terms of a measure reflecting the usefulness of the product system (the so-called functional unit). LCA distinguishes itself from other environmental evaluation methods by its holistic character. Errors of interpretation due to a partial environmental analysis should be avoided. LCA is still the only international standardised method to assess environmental performances of product systems (ISO 14040 up to 14043). There is a general consensus to aggregate the environmental impacts of the emissions and the resource use into scientifically sound impact categories (like energy resources, greenhouse potential, eutrophication etc.). On the other hand, there is no general agreement on a further aggregation of the impact categories, and each LCA has to present its own interpretation scheme. The categories soil quality, biodiversity and landscape are often neglected and methodological development is still required for a proper inclusion. An LCA is structured into four phases (see also Figure 3-1): • Goal and scope definition • Inventory analysis • Impact assessment • Interpretation These will each be described in brief in the sections below. Goal and Scope Definition Inventory analysis Interpretation Impact Assessment Figure 3-1 Components of a product life cycle assessment according to EN ISO 1997 For all phases of the LCA, the ISO norm stresses the importance of an objective, transparent and complete reporting. Methodological decisions as well as data collection must be completely transparent. For this reason all methodological procedures as well as all basic data used in this study were clearly and