Minimising Scope 3 Emissions by Electric Powertrain Design Optimization

Electric vehicles (EVs) do not produce local greenhouse gas (GHG) emissions during operation. However, their indirect emissions categorized as scope 3 according to the GHG protocol still result in a relevant carbon footprint and reporting of those emissions will be mandatory in the future. Accordingly, it is important to consider GHG emissions in the design of new EVs and aim at minimizing their emissions. In the present work, this is achieved by considering scope 3 emissions in a design optimization method for electric axle drives (e-drives). That way, the emissions of newly developed e-drives can be directly minimized alongside the optimization of other design objectives, e.g., production cost, energy efficiency and package integration. Furthermore, different supply chains are considered and characterized by their specific costs and GHG emissions. The supply chains include standard as well as low-carbon-footprint materials and different supply routes. As a result, a Pareto front of optimal design solutions for specified e-drive requirements is obtained. The method is applied to a case study, which involves the optimization of an e-drive for a passenger car. The obtained Pareto front and found trade-offs between scope 3 emissions, cost and energy efficiency are discussed, and a promising design solution from the Pareto front is selected to guide subsequent development. Results indicate a reduction potential of around 10% in scope 3 emissions compared to existing designs.