High-speed trains: is rail always better for the environment?

The Grand Pro­jet fer­rovi­aire du Sud-Ouest (GPSO) con­tin­ues to move for­ward des­pite oppos­i­tion. Work has begun to the south of Bor­deaux with a view to link­ing the cap­it­al of the Nou­velle-Aquitaine region with Toulouse via a high-speed line (LGV). Ulti­mately, the pro­ject will make it pos­sible to travel from one city to the oth­er in just 1 hour 05 minutes (1 hour 20 minutes with stops), but also to link Toulouse to Par­is (via Bor­deaux) in around 3 hours 25 minutes¹ – redu­cing travel times by between 49 minutes and 56 minutes. Some envir­on­ment­al­ists are opposed to this pro­ject, even though the train is one of the means of trans­port which is favour­able for the envir­on­ment­al transition.

The train is in fact one of the modes of trans­port to be favoured for the eco­lo­gic­al trans­ition. A fact that can eas­ily be veri­fied using ADE­ME’s My trans­port impact tool. The TGV emits 2.93 gCO₂eq per kilo­metre, where­as a com­bus­tion engine car emits 218 gCO₂eq, almost 75 times more. A jour­ney from Toulouse to Bor­deaux by TGV, accord­ing to this tool, cor­res­ponds to an emis­sion of 0.77 kgCO₂eq, com­pared with 53.4 kgCO₂eq by car².

So why might envir­on­ment­al­ists oppose the devel­op­ment of the train? The reas­on is that the way in which emis­sions are cal­cu­lated omits those res­ult­ing from the con­struc­tion of infra​struc​ture​.To reach speeds of up to 320 km/h, for example, cer­tain con­straints must be met. The lines must avoid excess­ively sharp bends or steep gradi­ents, lim­it­ing the pos­sib­il­ity of bypassing nat­ur­al areas, and also means the need for new infra­struc­ture. Hence, it’s not the train as such that’s being chal­lenged, but rather the scale of the works and the eco­lo­gic­al and eco­nom­ic con­sequences that their con­struc­tion will cause. The GPSO there­fore raises an essen­tial ques­tion: how is a pro­ject of this scale jus­ti­fied in terms of its cost and envir­on­ment­al impact?

The GPSO rep­res­ents an invest­ment of €14.3 bil­lion³ (estim­ated costs in 2021), of which €10.3 bil­lion will be devoted to the Bor­deaux-Toulouse line. A total of 418 km of lines⁴ are to be built between now and 2035 – 252 km to link Bor­deaux and Toulouse, with the remainder extend­ing the lines to Dax and, even­tu­ally, to Spain. A report on the socio-eco­nom­ic assess­ment of pub­lic invest­ment⁵ is used to eval­u­ate such a pro­ject in terms of benefits/costs. Patri­cia Per­ennes, an eco­nom­ist spe­cial­ising in trans­port and a con­sult­ant with Trans-Mis­sions, has worked for Réseau Fer­ré de France (RFF) and ques­tions this type of assessment.

“The Quinet report does an enorm­ous job of syn­thes­ising everything that is being done in inter­na­tion­al research. It pro­poses meth­ods for valu­ing the extern­al­it­ies of pub­lic invest­ment”, she explains. “For trans­port infra­struc­ture, each extern­al­ity, wheth­er pos­it­ive or neg­at­ive, is con­ver­ted into a mon­et­ary value.” In this way, a sort of bal­ance is formed between the value of the pos­it­ive and that of the neg­at­ive, mak­ing it pos­sible to val­id­ate an invest­ment project.

“There are extern­al­it­ies that are sim­pler to value, such as the quant­ity of CO₂ that a pro­ject will emit, the cost of its con­struc­tion, or the time it will save,” con­tin­ues the eco­nom­ist. “There are also extern­al­it­ies that can be com­plic­ated to value, such as defor­est­a­tion, or the dis­rup­tion of an eco­sys­tem. In these cases, com­pens­a­tion meas­ures will be more appro­pri­ate. But plant­ing a pine forest and cut­ting down trees that could be a hun­dred years old is not really the same thing.” In this case, around 4,800 ha of land⁶ are affected – 770 ha for Bor­deaux-Sud Gironde, 2,330 ha for Sud Gironde-Toulouse and 1,700 ha for Sud Gironde-Dax. The impact on biod­iversity, des­pite com­pens­at­ory meas­ures, is there­fore undeniable.

An expert report⁷, pro­duced by the École Poly­tech­nique Fédérale de Lausanne, assesses the vari­ous impacts of this pro­ject and the bene­fits it will bring, by com­par­ing it with anoth­er so-called ‘optim­ised’ scen­ario, itself pro­duced by RFF. The dif­fer­ence is that the optim­ised scen­ario focuses on renov­a­tion, and there­fore on the use of exist­ing lines. This scen­ario will not bring the same time sav­ings for users – 19 minutes will be saved com­pared with the cur­rent flow – but it will have a much lower envir­on­ment­al impact and cost. The con­clu­sion of this report is quite telling: “The experts were able to note that, faced with impacts of dif­fer­ent kinds, the assess­ment can only be a polit­ic­al one, as it depends on the adop­tion of a sys­tem of val­ues; it is there­fore bey­ond the com­pet­ence and remit of the experts. The issue is wheth­er to build a new line between Bor­deaux and Toulouse or to upgrade the exist­ing line. This is an emin­ently polit­ic­al issue.”

On the oth­er side of the bal­ance, there are the pos­it­ive extern­al­it­ies of the pro­ject: “For TGV pro­jects, sav­ing time is a key issue,” explains Patri­cia Per­ennes. “It is also quite expens­ive, espe­cially for pro­fes­sion­als. In 2010, for example, each hour saved by pro­fes­sion­als in the Île-de-France region was val­ued at €22. And these are the fig­ures for 2010, so with infla­tion it’s bound to have gone up.” Anoth­er import­ant part of pos­it­ive extern­al­it­ies is mod­al shift. It is estim­ated that, through the ‘trans­fer of traffic from road and air to rail’, the GPSO would enable ‘a total sav­ing of more than 2.3 mil­lion tonnes of oil equi­val­ent over 50 years⁸. A sub­stan­tial shift also rep­res­ents a major bene­fit in terms of green­house gas emis­sions, giv­en that in 2020 road trans­port accoun­ted for 94.7% of emis­sions from the trans­port sec­tor, itself the lead­ing source of green­house gases in France⁹ (28.7%)[…].

This interest in mod­al shift is also reflec­ted in the free­ing up of exist­ing tracks to give pri­or­ity to rail freight in par­tic­u­lar. This argu­ment is also being put for­ward for anoth­er French high-speed rail pro­ject that is the sub­ject of much debate. The Lyon-Tur­in line has also been in the news for years. In his 1998 report, engin­eer Chris­ti­an Brossi­er wrote that there were 100 goods trains and between 24 and 28 pas­sen­ger trains a day on the exist­ing lines in the Alps. How­ever, after numer­ous invest­ments in the region, the num­ber of trains has fallen year on year, while the num­ber of HGVs using one of the two tun­nels to cross the Alps has remained fairly stable¹⁰.

Using data from 1998, a simple cal­cu­la­tion shows the poten­tial of rail for transalpine trans­port in France: assum­ing 100 trains a day, each loaded with 30 con­tain­ers car­ry­ing around 18 tonnes, and run­ning 300 days a year, 16 mil­lion tonnes of goods could be trans­por­ted annu­ally. And, as Switzer­land is doing, 2/3 of heavy goods vehicles would be taken off the road in the North­ern Alps (Fréjus and Mont-Blanc). In com­par­is­on, in 2022, rail’s share of transalpine freight trans­port in France will be just 9.6%, or 2.3 mil­lion tonnes, while 22 mil­lion tonnes will be car­ried by road. These fig­ures high­light the gap between rail’s poten­tial capa­city and its actu­al use. This is why oppon­ents of the pro­jects will tend to favour altern­at­ives that involve work­ing on the oper­a­tion and renov­a­tion of exist­ing lines to make the best use of their capa­city. In fact, this is a nation­al ques­tion that has been raised: how is it that Switzer­land, with a net­work of 3,265 km of track, man­ages to run around 15,000 trains a day, while France, with its 27,483 km, only runs a sim­il­ar number?

Finally, as Patri­cia Per­ennes points out: “There is no doubt that if we talk about the flow on these new lines, the eco­lo­gic­al impact will be bene­fi­cial, but if we take into account the con­struc­tion phase, the cal­cu­la­tion is dif­fer­ent.” And des­pite the weight of the con­struc­tion phase, the GPSO is still expec­ted to be car­bon neut­ral by 2056. The dilemma of our time is embod­ied in this pro­ject: recon­cil­ing innov­a­tion, effi­ciency and envir­on­ment­al pro­tec­tion is no easy task. 

Pablo Andres