Transportation in a 100% renewable energy system

February, 2018

Antonio García-Olivares, Jordi Solé and Oleg Osychenko, MEDEAS partners from the Institute of Marine Sciences (ICM), Spanish Council of Scientific Research (CSIC) have published a scientific article in the Energy Conversion and Management Journal, titled “Transportation in a 100% renewable energy system”

This study reviews the technologies and systems that are being proposed or proven as alternative to fossil-fuel based transportation, and their prospects for their entry into the post-carbon era, from both technological and energetic viewpoints. It also provides estimations of the energy costs for such transition under conservative assumptions.

A 100% renewable transport providing the same service as global transport in 2014 would demand about 18% less energy. The main reduction is expected in road transport (69%), but the shipping and air sectors would notably increase their consumptions: 163% and 149%, respectively. This is derived from the need to produce natural gas from electricity in order to power the engines of planes and boats and assuming an airplane transportation reduction of 50%.

Energy End Use Final Energy in 2014 (PJ) Future Final Energy (PJ)

Road

82725

25293

Rail

2195

1386

Shipping

10383

27255

Air

11556

24614 / 28774 / 48150 *

Pipelines/Fuel transport

114

97

Total Transport

101585

78646 / 82806 / 102182 *

Table 2. Estimated energy used for present and future transport, by sector. * The three values correspond to the use of hydrogen, methane and jet fuel, respectively, as the main fuel for the aircrafts.

According to this study, a set of measures to anticipate the possible risks in the transition is recommended. Such measures should be supported and fostered by governments and civil society:

  • Substitution of most of the current inter-urban land transport, which is based on trucks and private cars, by electric trains for freight and passengers.
  • Use of EVs (Electric Vehicles) only for short-distance transport between cities with no public transport alternative.
  • Limited use of EVs, which translates into a relatively small fleet. The same size as present could be considered an upper limit, but it would not solve congestion problems in cities, could increase prices of important metals such as Ni and Li, and could put in danger their availability for other industrial uses. Priority should be given to electrified public transport.
  • Use of fuel cells only when autonomy and power requirements of the vehicle demand it.
  • Reduction of aviation fleets in favour of (i) rail systems and (ii) marine transport, in this order.
  • Reorganization and reduction of marine traffic, as cargo vessels are major consumers of fuels (as of present) and hydrogen and biogas fuel cells (in the future).
  • Optimization of logistics and work, in order to reduce travel demand.
  • Shifting transport ‘modes’ from high to low energy intensity. Appropriate parameters to quantify this intensity and prioritization modes would be kWh per passenger-km and kWh per Tm-km.
  • Improvement of energy efficiency not only by using the best technologies available but also by acting on urban and public transport infrastructures. Fostering of TaaS (Transport as a Service) and car-sharing have great potential to decrease demand for energy and materials for road transport.

Another conclusion of this study is that a renewable transport system is feasible but not necessarily compatible with the usual exponential growth of resource consumption. We are entering an age where the investments required in the next few decades will involve the use of large fractions of the reserves of important metals such as Cu, Ni, Li, Pt and Pa. Some of these metals (e.g. Pt and Pa) have specific physical properties that make them essential. Therefore, any policy for the necessary renewable transition may no longer be based exclusively on prices and incentives, but must also consider geological reserves and material scarcity. In the next 50 years, the lack of elasticity of metal reserves will probably hasten the necessity for designing a post-capitalist economy, which will use new economical tools. Some of these tools would be the use of geophysical and sustainability indicators, abandonment of GDP as the main indicator of economic success, incorporation in the economy of long-term planning and scientific environmental assessment and, most importantly, introduction of new mechanisms which may create prosperity without necessarily increasing the consumption of resources and materials.

Persons involved: 
Antonio García-Olivares
Jordi Solé
Oleg Osychenko