06/04/2023

A study on Zero-Carbon Combined Transport

The study ‘Zero-Carbon Combined Transport: Technology and efficiency analysis of
zero-carbon road-rail combined transport‘ was conducted by d-fine in close cooperation with UIRR (International Union for Road-Rail Combined Transport).

The technology perspective on sustainable transport

In order to achieve zero-carbon transport, it is important to promote the use of propulsion technologies that enable the use of zero-carbon fuels and energy sources while focusing on the greatest energy efficiency achievable. This study expands on the energy efficiency of different transportation modes and propulsion technologies through comparative analysis. In this report, energy efficiency as well as the greenhouse gas
(GHG) emissions in CO2 equivalents well-to-wheel are estimated in order to understand which propulsion technologies already enable zero-carbon transport and are efficient at the same time. Battery electric vehicles have particular potential for use on road legs in CT, therefore different battery technologies are compared by cell voltage and energy
density, followed by an outlook on the EU’s path for decarbonized electricity generation:

  • Energy-efficiency of transportation modes: Energy efficiency is influenced by aerodynamic drag, which increases proportionally to the square of the speed. Aerodynamic aspects influence further techniques to improve aerodynamics.
  • Propulsion technologies for heavy-duty vehicles: Combustion is a main contributor to CO2 emissions, other, more sustainable propulsion technologies (e.g., battery or fuel-cell electric drive) receive more attention.
  • The development of battery technologies: Llithium-ion batteries are the preferred choice by today’s vehicle manufacturers due to their relatively good energy density. However, the global lithium resources might not be able to sustain the electrification of transport.
  • Decarbonization paths for electricity generation: For rail transport with energy-efficient electric trucks and electrified transshipment technology electrically powered means of transport, the emissions directly depend on the emission intensity of power generation. Thus, the use of electricity from renewable sources facilitates zero-carbon transport.

Costs and investment needs for zero-carbon combined transport

  • Electrification of terminal equipment: Except for RMGs which are typically electric, the equipment is powered by diesel engines and therefore emits GHGs. In the following, the electrification potential and the purchase price of different transshipment equipment are assessed.
  • Electrification of rail infrastructure: Considering railway infrastructure, electrification of the line tracks is laid out as one of the requirements for the core network until 2030.
  • Electrification of trucks: BEVs are a promising technology for CT, considering the existing infrastructure, their high energy efficiency, and low emissions. However, as a consequence of electrifying transport on road legs, investments in new battery electric trucks have to be made.

Technological developments beyond propulsion

  • Impact on rail transport‘s energy efficiency:  The use of a 740 m train instead of a 600 m train results in an efficiency gain of about 12 % per tonne-kilometre. Therefore, using longer trains is an essential step towards more efficient rail freight transport.
  • Impact on road freight transport‘s energy efficiency: The efficiency gain from using 25.25 metre-long trucks instead of trucks with a length of 16.5 m can be quantified by 15 %.

Conclusions

  • Range of energy efficiency and carbon footprint of door-to-door CT and long-haul trucking: Combined transport is 40 % – 70 % more efficient than road freight transport already today, but it is not yet fully zero-carbon. In this study, the energy efficiency and emissions aspects are presented for the different transport modes.
  • Outlook for zero-carbon door-to-door combined transport: The necessary emission reduction from the transport sector can be achieved by creating bridges between the silos to achieve the inclusion of modes that are inherently more efficient and have the potential of being completely zero-carbon already today.

Access the full study document HERE.