Strategic Selection of Future EV Technology based on the Carbon Payback Period

The British Low Carbon Vehicle Technology Project (LCVTP) has developed technologies for future plug-in vehicles. Simulation results indicate significantly lower tailpipe CO₂ emissions when compared to conventional internal combustion engine technology, but how good are the CO₂ savings on a life cycle basis? Do these technologies have higher embedded CO₂ from vehicle production? If so, can this be paid back within the lifetime of the vehicle? To help answer these questions, building on work completed within LCVTP, Ricardo conducted a life cycle top-down review of hybrid and EV technology architectures to estimate the CO₂ emissions associated with each phase of the vehicle’s life. Results showed that these technologies have the potential to reduce the life cycle CO₂ footprint of passenger cars, compared to today’s conventional technology. However, the higher embedded CO₂ from vehicle production has to be paid back before these savings can be realised. This carbon payback period is highly dependent on the CO₂ emissions resulting from electricity generation and transmission. This implies that the commercial role out of plug-in vehicles must happen in tandem with decarbonisation of the electricity to ensure CO₂ emissions are really reduced. Ensuring future low carbon vehicles are truly low carbon will require a shift in focus from tailpipe CO₂ to considering the environmental impact of the whole vehicle life cycle and the energy it uses. By adopting a life cycle philosophy and considering the carbon payback, vehicle manufacturers, policy makers and consumers can select the appropriate low carbon technology for their situation.