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Can we really divide by 4 CO2 emissions from transport in France?

 Grégory Launay - Last update: February, 5th 2013


Stress reduction greenhouse gas emissions, described by the IPCC suggests (to say the least ...) a halving of global CO2 emissions in 2050. Countries declined by this goal is, in France, a division by 4 emissions compared to 1990 levels.

What does such a constraint for transport in France? I suggest you start by looking at what people are saying with a little thought to the problem. 

This question is precisely the subject of a study conducted by the Laboratory of Transport Economics and published in April 2008 in the framework of a European research program.


What remedies to heal the sick?

 There are different ways to achieve this goal. The most traditional posture is to reject the problem in the field of technology. This is what has been done so far by focusing effort on reducing emissions per unit of automobiles rather than overall reduction. 

History and emissions regulations in Europe - Source: Association of T & E, Final Report 2009

And we can just see that it did not prevent global emissions related to transportation to increase .... due to an overall amount of transport (the number of kilometers traveled per person per year) always increase. 

CO2 emissions from road transport in some countries of the European Union - Source: Ministry of Ecology, 2009

There are other ways to reduce emissions including those more "political" to reduce the overall mobility (number of kilometers traveled per person per year).

But reduce mobility by four does not a snap! This could happen in a disaster scenario thistle but out of this economic scenario, this implies a spatial organization quite different from what we know today.


What are the assumptions of the study of LET?

The prospective study that I suggest you look aims to explore the conditions that respect "factor 4" for transport in France. For that it considers five main determinants in CO2 emissions relating to transport: 

  • technologies: performance cars and type of energy used (gas, electricity etc..
  • public policy: taxes, investment in research, infrastructure development
  • the organization of space: housing density, distance between home / work, cost of transport, etc..
  • the demographic and economic context
  •  lifestyles: the time that people are willing to spend on transportation

The approach of the study is to determine a possible path from a known starting point (2000), constraints on the endpoint (CO2) and formalized rules changes (a mathematical model).

In all cases studied, the demographic and economic context is considered to evolve trend. In other words, there is no major disaster: thistle economic war, etc..

Gross domestic product doubled between 2000 and 2050 (1,500 billion euros in 3000). Population increased by 13% over the same period to reach 67 million. 

The assumptions for technological developments are: 

  • incorporation of 35% biofuels by 2050
  • an introduction to the auto market different "technological packages" ranging from thermal engine optimized fuel cells
  • an evolution of the carbon contained in electricity consistent with the objective factor 4 as seen by the Energy Commission of 2007 ... I'm not quite sure what is meant by this hypothesis, but it should at least consider a maintained contained the low carbon electricity in France ...

One can of course question the relevance of these assumptions, including the 35% biofuels, but still. Only the most aggressive technology package gives interesting results:

  • the "package 2.4" which describes a generalization of PHEVs with 100 km of autonomy
  • a variant which describes a generalization of fuel cell vehicles

Penetration curve technology is described below: 


Penetration curve of new technologies - Source: Study Mobility 2050, LET 2008


What are the different scenarios studied?

The study proposes to examine three types of scenarios, corresponding to different assumptions about the evolution of these five drivers. 

Until now, the increase in average speed transport was correlated to the increase in gross domestic product that has allowed people to be able to move without spending increasingly more time (see Zahavi's hypothesis). This was done thanks to the development of transport faster (voitrue, TGV, airplanes) but also thanks to the development of infrastructure (including highways axis). 

The first type of scenario, called Pegasus, considers these past observations remain true in the future. This is the most orthodox vision that focuses solely on the technological evolution in the context of "always faster, stronger, higher." 

The other two types of scenarios, constraints, introducing a break in these findings: the average speed increasing. This implies, for each person, a stagnation distance is increased traveling time. 

The second type of scenario, called Chronos, deals with the case where the traveling time increases. It continues to move more but travel speeds stagnate, it spends more time. As we shall see, this assumption implies a drastic reduction in the use of the car to the train (called different modal). 

The last type, called Hestia, treats the case where the distance is stagnating. As travel speeds stagnate and that we do not accept to spend more time in transport, distances also stagnated. This scenario calls into question the organization of space and demand for global mobility.


That essentially say the results?

The study aims to describe the outskirts of the overall evolution of mobility in each of the scenarios. 

In the scenario Pegasus (two variants are shown here) mobility believes nearly half to go from 950 to 1450 Giga passenger-km. This is quite normal, this scenario only prolongs the evolution we know from nearly two centuries. 

The scenario describes Chronos also a very strong increase in traffic but it is especially here that believes the train significantly. Travel by private vehicles are lower, they fell by 7% between 2000 and 2050 (678 Gpkm against 728). 

Finally, in the scenario Hestia, mobility is stagnating. Travel speeds are identical to those of 2000, the time also. Logically the distances traveled by people are too. Overall traffic increase of 13% which corresponds to the hypothesis of evolution of the population. So far everything is very logical.


Evolution of global mobility in France - Source: Study Mobility 2050, LET 2008

This graph shows from left to right transport volume for the year 2000 as reference year 2050 according to the different scenarios. This volume is detailed in embodiment (private car, public transit, and plane TGV). The key point is that only the scenario "technological" (Pegasus) provides a glimpse increased mobility car. For the other two, we must speak of "decay" of the particular vehicle ... this study it would be politically incorrect?

The model used in the study deduces then CO2 emissions by 2050 for each of the scenarios considered. The results for the technology package 2.4 (hybrid rechargeable) deployed from 2010 are:



Evolution of CO2 emissions related to transport in France - Source: Study Mobility 2050, LET 2008

This graph shows from left to right baseline emissions in the year 2000 and those estimated for different scenarios. Are shown for each scenario, the share of CO2 from passenger transport, the transport of goods to and from the generation of electricity used. The red line indicates the target "factor 4" reach.

Marking two points are worth noting:

  • the technological scenario (Pegasus), the technological assumptions, however, are very optimistic (that is to say the least), sometimes painfully a reduction by a factor 2
  • none of the scenarios reaches the respect factor 4

The condition for achieving technological factor 4 in the scenario Pegasus are widespread fuel cell at the latest by 2025, fueled with hydrogen produced exclusively from renewable (and therefore CO2 emissions indirect void). 

To summarize, if we continue current policies, believing that we can achieve the returns to bet that we will win the lottery!

Evolution of CO2 emissions from transport in France - Source: Study Mobility 2050, LET 2008

One may question the technological package described here. Why not keep PHEV or even all electric, so the electricity would be made from renewable? Consider the deployment of carbon-free hydrogen vehicle is multiplied by 3 renewable energy demand ....

Other scenarios (Chronos and Hestia), offset the decline of the car by a massive expansion of public transport with a TGV traffic increased between 5 and 7 (just that)! These scenarios describe a reality so drastically different from today.


What lessons?

As with any prospective study can be critical of the methodological choices, assumptions (especially technology) ... But the key is not. This study mainly the merit of showing that the purely technological trend is probably an illusion. Yet it is this vision that will support most public and private actors. At best, a very proactive approach saves a factor of 2 by the deployment of technologies. Otherwise it'll have to find something else.

Design reduced mobility? A decrease in speed? It seems impossible today. Two industrial revolutions we are too accustomed to this continuous movement, this habit of always higher, stronger, faster. This is especially true because the automotive industry is at the heart of the industry (and thus employs) in Europe, the United States, Japan, China ... The reaction of governments during the last "crisis", with the introduction of scrappage, shows how the production (and use) the car is considered vital for the economy.

However, what this study shows is that overall reduction in car travel will probably be essential to meet the recommendations of the IPCC on global warming.

What is true for France is elsewhere. France has rather more advantages than other developed countries (low carbon electricity, well developed rail network, etc..). Do not forget that this constraint "factor 4" becomes a factor of 10 when declined for the United States ...