A lifecycle comparison of natural resource use and climate impact of biofuel and electric cars

Abstract

Here we compare the biomass feedstock use, primary energy use, net CO2 emission, and cumulative radiative forcing of passenger cars powered by different energy pathways. We consider the full lifecycle of the vehicles, including manufacture and operation. We analyze battery electric vehicles (BEVs) powered by standalone electricity generation using woody biomass, with and without CCS, and with integration of wind electricity. We analyze internal combustion vehicles (ICVs) powered by fossil gasoline and by biomethanol derived from woody biomass, with and without carbon capture and sequestration (CCS). Our system boundaries include all fossil and biogenic emissions from technical systems, and the avoided decay emissions from harvest residue left in the forest. We find that the pathways using electricity to power BEVs have strongly lower climate impacts, compared to the liquid-fueled ICV pathways using biomethanol and gasoline. The pathways using bioelectricity with CCS result in negative emissions leading to global cooling. The pathways using gasoline and biomethanol have substantial climate impact, even with CCS. Regardless of energy pathway, smaller cars have consistently lower climate impact than larger cars. These findings suggest that accelerating the current trend toward vehicle electrification, together with scaling up renewable electricity generation, is a wise strategy for climate-adapted passenger car transport.