The influence of electricity allocation rules in environmental assessments of electric vehicles

Which electricity mix should be considered when performing an environmental assessment of electric vehicles? The electricity mix, that a Life Cycle Assessment (LCA) practitioner choses to allocate to an electric vehicle (EV), has a large influence on the environmental score. The allocation of an electricity mix has created confusion about the environmental impact of an electric vehicle and the choice itself is prone to methodological inconsistency. Electric vehicles and their electricity demand are not solely responsible for momentary marginal changes in electricity mixes. The electricity producers themselves define the electricity mix at a given moment in time, taking various parameters (such as expected and extra demand, prices, regulations, taxation) into account. Can it be justified that these marginal changes are allocated to electric vehicles? Today, different approaches exist to allocate a certain share of the electricity market to new consumers. Unfortunately, the different points of view yield contradicting results that are misleading the interpretation and the decision support. The different ways to allocate electricity to an electric vehicle are analysed in this paper.