Methodology for calculating use-phase emissions for eMobility subsystem products

eMobility is a well-recognized de-carbonization lever that is expected to capture about 7% of road vehicle fleet by 2030. To accurately estimate its contribution to decarbonization, Life Cycle Assessment (LCA) is imperative as it quantifies potential environmental impacts across a product’s life from cradle to grave. For eMobility products involved in energy transformation, the use-phase is predominant among the various lifecycle phases. However, existing global methods for calculating use phase emissions, such as Green House Gas (GHG) Protocol, still have ambiguities in its practical application. This paper attempts to bridge that gap and present a framework for calculating product use-phase emissions from components in a typical Battery Electric Vehicle. The use-phase emissions comprise of direct emissions (product's actual energy consumption and energy losses) and indirect emissions (mass-induced emissions). The direct emissions are calculated by segmenting the product functions into drive modes, regeneration, charging, parking, etc. and determining energy loss for each stage. The testing data is incorporated into a Worldwide harmonized Light duty Test Cycle (WLTC) to simulate real-world driving conditions. The calculated energy loss is adjusted with both upstream, downstream component efficiencies and regeneration. The loss calculations from one WLTC cycle are extrapolated across the product’s service life for total operational energy loss from product. The mass-induced indirect emissions are calculated by the concept of Energy Reduction Value through powertrain simulation model involving driving and powertrain physics with various vehicle parameters. Service life energy consumption from the product is equated with region specific emission factor to give the total use-phase emissions. The methodology has been applied successfully to Eaton’s eMobility portfolio of products and is replicable for any eMobility subsystem. It also provides insights on design levers that can improve the GHG performance of the vehicle holistically.