Saving energy in passenger car transport: between efficiency improvement and increasing car size

Panel: 4. Transport and mobility: How to deliver energy efficiency

This is a peer-reviewed paper.

Author:
Amela Ajanovic, Vienna University of Technology, Austria

Abstract

Improving the energy efficiency of passenger cars is considered as an important means for saving energy and reducing CO2-emissions in transport sector. In the last years according to the European policy and goals, average fuel intensity of new passenger cars decreased significantly. However, a large part of these improvements was lost due to the increasing size of cars.

The core objective of this paper is to analyse the change of energy consumption of passenger cars along the energy service (mobility) providing chain (well-to wheel) of different car types cars (diesel-, gasoline-, natural gas-, battery electric- and fuel cell vehicles) with special focus on the impact of the size of new cars.

The major results of this investigation are: (i) with respect to WTT there are considerable differences between biofuels as well as electricity and hydrogen produced from renewable and fossil energy sources; (ii) regarding power-specific fuel intensity there was a decrease of more than 40% since 1990; that is to say, efficiency in 2010 was much higher than in 1990. (iii) However, about half of these theoretically possible energy savings has been compensated by the switch to larger cars and virtually the same effect can be seen for specific CO2 emissions.

This leads to the final conclusion that future energy policy has to address the size issue e.g. by means of size-dependent registration taxes.