Are electric vehicles more efficient? A slacks-based data envelopment analysis for European road passenger transportation

The deployment of electric vehicles (EVs) is rapidly progressing worldwide, and energy efficiency is an important indicator for both the economy and the environment. It is necessary to verify whether EVs are more energy efficient than internal combustion engine (ICE) vehicles. However, studies have yet to evaluate the energy efficiency of EVs using the data envelopment analysis (DEA) approach. To fill this research gap, this paper evaluated the energy efficiency of EVs for road passenger transportation using a slacks-based measure (SBM) approach in six European countries from 2012 to 2018. EVs have been separated from the entire transport sector and compared to ICE vehicles. In the case of EVs that use electricity as fuel, the primary energy supply must be used as energy input to reflect conversion loss during power generation. The primary energy supply was calculated by applying the power generation efficiency of each country for use as an energy input to reflect conversion loss. EVs were more energy efficient than ICE vehicles in four out of six countries but less energy efficient in two countries. Based on the measured slack results, the potential energy savings were quantified, and the main factors in reducing energy efficiency were identified.