Battery Electric Vehicles (BEV) are a well-recognized de-carbonization lever that is expected to capture about 15% of road vehicle fleet by 2030 [1, 2]. A large number of organizations are committing to science-based targets (SBTi) and are following roadmap strategies towards Greenhouse Gas (GHG) reduction including all value chain players such as material suppliers, component manufacturers and OEMs [3]. In BEVs, several components are involved in energy transformation and delivery. These components themselves consume energy, and therefore are a cause of GHG emissions during their use. To quantify their contributions and help corporations progress towards decarbonization strategies there is a need for robust use phase calculation methodology. Existing global methods for calculating use phase emissions, such as Green House Gas (GHG) Protocol (version 1.0), provide a good framework, but still have uncertainties 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 BEV. The use-phase emissions comprise of direct emissions (product's actual energy consumption and energy losses) & 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 product power loss testing data is incorporated into a Worldwide harmonized Light duty Test Cycle (WLTC) to simulate standardized driving conditions [4]. The calculated energy loss is adjusted with upstream component efficiencies. 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 (ERV) through powertrain simulation model involving driving and powertrain physics with various vehicle parameters considered [5]. Service life energy consumption from the product is multiplied 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 electrical mobility subsystem. It also provides insights on design levers that can improve the GHG performance of the vehicle holistically.