Even studies of a single product (hot-spot-identification) are typically later used in a comparative context, since the ultimate goal often is to improve the studied systems, thus supporting decisions that involve comparisons, even if indirect. Most LCA studies are actually aimed at decision support involving a choice or substitution between two product systems. This implies that in such a system, the consequences are traced forward in time, which means that it is relevant to use data on marginal suppliers and substitution of displaced activities.
#Displacement allocation openlca full
A consequential product system can be used to answer the question: “What are (the environmental impacts related to) the full share of those activities that are expected to change when producing, consuming, and disposing of the product?” Thus, the purpose of consequential modelling is decision support. In such a system it is relevant to use data on specific or market average suppliers, and to partition them according to the chosen allocation rule. An attributional product system can be used to answer the question: “Under the specified normative allocation rule, what are (the environmental impacts related to) the allocated shares of the activities that have contributed to the production, consumption, and disposal of the product?” Thus, the purpose of attributional modelling is to trace a specific aspect of the product (as determined by the allocation rule) back to its contributing unit processes. The two models answer different questionsĪnother way of describing the difference is in terms of the questions that the two models can answer: In the right circle, consequential LCA seeks to capture the change in environmental exchanges that occur as a consequence of adding or removing a specific human activity. In the left circle, attributional LCA seeks to cut out the piece with dotted lines that belongs to a specific human activity. 
The circles represent the total global environmental exchanges. The conceptual difference is illustrated in the figure below.įigure: The conceptual difference between attributional and consequential LCA. Consequential approach: System modelling approach in which activities in a product system are linked so that activities are included in the product system to the extent that they are expected to change as a consequence of a change in demand for the functional unit.Īs it is clear from the definitions the two methods vary greatly.
Attributional approach : System modelling approach in which inputs and outputs are attributed to the functional unit of a product system by linking and/or partitioning the unit processes of the system according to a normative rule. The two Life cycle assessment approaches are defined as follows in the UNEP/SETAC Shonan guidance on LCA ( UNEP 2011), italics added: But in this section we explain what the difference to attributional modelling is and why and when consequential modelling is the right choice for your LCA. The examples on this website are exclusively about consequential LCI modelling. The analysis is completed with a comparison of GHG emissions with the results of previous LCA studies.For life cycle inventory analysis (LCI) it is common to distinguish between consequential and attributional modelling. The dependence of impacts on LC mileage is investigated for both propulsion technologies and the break-even point for the effective environmental convenience of electric car is determined considering several use phase electricity sources. The eco-profile of the different vehicle configurations is assessed and the main environmental hotspots affecting conventional and electric cars are identified and critically discussed. The inventory is mainly based on primary data and the assessment takes into account a wide range of impact categories to both human and eco-system health. The analysis follows a “from cradle-to-grave” approach and it captures the whole Life-Cycle (LC) of the car subdivided into production, use and End-of-Life stages. 
This study presents a comparative Life Cycle Assessment of Internal Combustion Engine (ICE) and electric vehicles. As a consequence, the need for higher fuel/energy efficiency in both conventional and electric cars has become urgent and the efforts across industrial and research players have proposed a range of innovative solutions with great potential. Considering the European Union, light duty vehicles are responsible for roughly 10% of total energy use and air emissions. Transportation represents one of the major contributors to several environmental burdens such as Green-House-Gas (GHG) emissions and resource depletion.
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