Freight transport: the way out of fossil fuels

Freight trans­port is now largely depend­ent on fossil fuels, both for glob­al logist­ics chains and in France. Heavy goods vehicles and light com­mer­cial vehicles are mainly dies­el-powered. The same is true for river trans­port boats, while mari­time trans­port runs on heavy fuel oil. Air freight depends on par­affin. Only rail freight has already made a sig­ni­fic­ant shift away from liquid fuels and oil.

To meet the cli­mate chal­lenge, decar­bon­isa­tion of the sec­tor is essen­tial, but has not yet begun. While the first art­icle in this series poin­ted out the five levers for decar­bon­ising freight trans­port (mod­er­a­tion of trans­port demand, mod­al shift, vehicle filling, vehicle energy con­sump­tion, energy decar­bon­isa­tion), this one focuses on the last lever of energy decar­bon­isa­tion. And asks: what are the tech­no­lo­gic­al options for mov­ing freight trans­port away from its depend­ence on oil?

It is pos­sible to give 5 main cat­egor­ies to find your way through the tech­no­lo­gic­al options for doing without oil in trans­port. The first option is to switch to elec­tric, about 90% of which is already low car­bon in France¹. Elec­tric motors are also more energy effi­cient than com­bus­tion engines, which makes them a pre­ferred option when pos­sible. Because the volume of bat­ter­ies to be car­ried makes elec­trics unthink­able for cer­tain heavy modes, such as air or sea trans­port (apart from a few niche applic­a­tions over short distances).

Anoth­er option that relates to elec­tric is hydro­gen. The main means of low-car­bon hydro­gen pro­duc­tion envis­aged is indeed the elec­tro­lys­is of water, which requires elec­tri­city. And in addi­tion to the intern­al com­bus­tion engine option for using hydro­gen in the vehicle, the fuel cell option allows the hydro­gen to be con­ver­ted back into elec­tri­city for use in an elec­tric motor. The main advant­age of hydro­gen is that it elim­in­ates the con­straints of range and bat­tery rechar­ging, par­tic­u­larly for heav­ier vehicles. How­ever, hydro­gen pro­duc­tion is still 95% depend­ent on fossil fuels, and is a less energy-effi­cient option than dir­ect elec­tri­fic­a­tion, which still presents many tech­nic­al and eco­nom­ic chal­lenges for its deploy­ment in transport.

Anoth­er gas that is often men­tioned is meth­ane, also called nat­ur­al gas for its fossil-derived ver­sion, or bio­gas or renew­able gas for the low-car­bon-derived ver­sions. Only this bio­gas is inter­est­ing from cli­mate point of view. But, although it is grow­ing rap­idly, gas pro­duc­tion from bio­mass meth­an­isa­tion (agri­cul­tur­al efflu­ents, inter­me­di­ate crops, bio-waste, co-products, or crop residues, etc.) will only account for around 2% of gas con­sump­tion in France in 2022². And bio­gas will only be able to account for a very sig­ni­fic­ant share of gas con­sump­tion if there is a sharp drop in the volumes con­sumed, which today are mainly in the build­ing and indus­tri­al sectors.

Liquid bio­fuels are also pro­duced from bio­mass. They are more developed and are already incor­por­ated into road fuels, up to a little over 8% in 2022 for dies­el³. How­ever, the pro­duc­tion of this biod­ies­el is far from being vir­tu­ous to date: more than three quar­ters of the raw mater­i­als used are impor­ted, most of them come from crops that com­pete with food uses⁴, and the reduc­tions in CO₂ emis­sions are very lim­ited com­pared to oil, when all the impacts are considered.

Finally, syn­thet­ic fuels (or elec­tro­fuels or e‑fuels) are at the inter­face of sev­er­al energy car­ri­ers already men­tioned. They con­sist of using low-car­bon elec­tri­city to pro­duce hydro­gen, which is com­bined with CO₂ (or nitro­gen for e‑ammonia) to make liquid or gaseous fuels⁵. Their main advant­age is that they can replace many of the fuels cur­rently in use, without any modi­fic­a­tion to vehicles. On the oth­er hand, they suf­fer from many chal­lenges: their pro­duc­tion is only in its infancy, and must be based on very low-car­bon elec­tri­city in order to present a largely favour­able car­bon bal­ance; the elec­tri­city require­ments for their pro­duc­tion are very high, in the order of 4–5 times high­er for e‑diesels than for dir­ect use in an elec­tric vehicle⁶; as a res­ult, their cost is also very high, even more so in the short term⁷.

It is clear from these dif­fer­ent options that their cur­rent car­bon foot­print is quite var­ied, depend­ing on the level of decar­bon­isa­tion of these dif­fer­ent ener­gies or energy car­ri­ers. For the moment in France, only elec­tri­city is largely decar­bon­ised. There­fore, the levels of deploy­ment, but also the con­straints and chal­lenges to be met for their devel­op­ment are var­ied. This invites us to try to find the most rel­ev­ant energy mix accord­ing to the many issues to be integ­rated (tech­nic­al, eco­nom­ic, cli­mat­ic, resources, etc.).

Road trans­port accounts for three quar­ters of green­house gas emis­sions from goods trans­port in France (includ­ing inter­na­tion­al trans­port), with 60% from heavy goods vehicles and 16% from light com­mer­cial vehicles. For the lat­ter vehicles and for HGVs oper­at­ing in the last few kilo­metres or the shortest dis­tances, elec­tric power should rap­idly become the dom­in­ant engine. For longer dis­tances, com­pet­i­tion is stronger and illus­trates a sig­ni­fic­ant con­flict between the most envir­on­ment­ally friendly options and the avail­ab­il­ity of these solu­tions, par­tic­u­larly in the short term.

The fig­ure above shows that, as of 2020, three options allow for very sig­ni­fic­ant reduc­tions in green­house gas emis­sions for road tract­ors⁸. These same options will even achieve reduc­tions in the order of a six­fold reduc­tion for a truck sold in 2030 com­pared to dies­el⁹.

Sales of gas-fuelled trucks accoun­ted for 4.5% of the mar­ket in 2022 for trucks over 7.5 tonnes and rep­res­ent the lead­ing altern­at­ive energy to dies­el¹⁰, but bio­gas is only avail­able in lim­ited quant­it­ies¹¹. The pro­duc­tion of low-car­bon hydro­gen is only in its infancy and the sup­ply of trucks is not expec­ted to take off strongly before 2030. Finally, the sup­ply of elec­tric trucks is low to date, and they accoun­ted for only 0.3% of truck sales in 2022 in France¹².

How­ever, in early 2023, the European Com­mis­sion pro­posed a revi­sion of the CO2 emis­sion stand­ards for new heavy goods vehicles, aim­ing for a 45% reduc­tion in these emis­sions in 2030 com­pared to 2019¹³. The main man­u­fac­tur­ers already seem to be in line with this object­ive and are aim­ing for around 50% of sales of heavy goods vehicles with zero emis­sions by the end of the dec­ade¹⁴. This tar­get will be met mainly by elec­tric vehicles, sup­ple­men­ted by a smal­ler pro­por­tion of hydro­gen trucks.

It should be noted that elec­tric vehicles could also be deployed over long dis­tances with the help of elec­tric high­ways, which allow vehicles to recharge dur­ing their use by modi­fy­ing the infra­struc­ture (elec­tri­fic­a­tion by caten­ary, rail, or induc­tion)¹⁵. While these tech­no­lo­gies make it pos­sible to reduce the con­straints linked to the bat­ter­ies, their range, and their rechar­ging (high power demands for rap­id rechar­ging, pause times, etc.), the choice of the tech­no­logy to be favoured is still not very mature and deploy­ment would require coordin­a­tion at European level to be of real interest.

This example also shows the dif­fi­culty in choos­ing the engines and tech­no­lo­gies to be pre­ferred. The diversity of decar­bon­a­tion options is obvi­ously an asset and can help gain resi­li­ence accord­ing to future con­straints. How­ever, no solu­tion is per­fect, and it will not neces­sar­ily be effi­cient or even pos­sible to invest in the sup­ply or rechar­ging infra­struc­ture for all decar­bon­isa­tion options, or for man­u­fac­tur­ers to invest in all engines at once. It is pos­sible that one or two options will end up being the most pop­u­lar for each mode, wheth­er for heavy goods vehicles or for oth­er modes.

For the oth­er modes of trans­port, a mix of dif­fer­ent tech­no­lo­gies is often men­tioned. For inland water­ways, con­ver­sion to bio­fuels or bio­gas is the easi­est to envis­age from a tech­nic­al point of view. But hydro­gen or even elec­tric power could also play a role in decar­bon­ising this mode, because of the dis­tances or even volumes that are still reas­on­able to ima­gine car­ry­ing bat­ter­ies (which are heavy) or hydro­gen (which takes up a lot of space).

For mari­time trans­port, gas-powered ships and then con­vert­ing them to bio­gas have long been the pre­ferred way of mov­ing away from oil. Sail­ing ships are also likely to devel­op, at least as a propul­sion aid. There is also increas­ing talk of syn­thet­ic fuels, in par­tic­u­lar e‑ammonia or e‑methanol for this mode, which is likely to be par­tic­u­larly long and dif­fi­cult to decar­bon­ise. The same applies to air trans­port, where the trans­ition from oil should be based primar­ily on second-gen­er­a­tion bio­fuels, syn­thet­ic par­affin or hydro­gen for applic­a­tions that allow it.

Finally, the rail­ways are already largely elec­tri­fied, but about 15% of their energy con­sump­tion is still based on dies­el¹⁷. The elec­tri­fic­a­tion of lines is the most effi­cient solu­tion and could be fur­ther exten­ded. For the lines that will remain non-elec­tri­fied, bat­tery elec­tric, bio­fuels and hydro­gen are the main altern­at­ives¹⁸.

What are the implic­a­tions for the energy transition?

To move away from oil, freight trans­port will have to rely on a vari­ety of ener­gies in the future, while pas­sen­ger trans­port will be largely dom­in­ated by elec­tric power (as illus­trated by the four ADEME Transition(s) 2050 scen­ari­os below¹⁹).

Whatever the mode, decar­bon­isa­tion is likely to be slow, costly, or face major tech­nic­al and imple­ment­a­tion chal­lenges. The main decar­bon­isa­tion options also depend on resources (metals, bio­mass, elec­tri­city, etc.) that are under pres­sure, wheth­er with­in trans­port, with oth­er sec­tors of the eco­nomy or because of the impacts linked to their exploit­a­tion con­di­tions (impacts on biod­iversity, geo­pol­it­ics, social, etc.).

This should lead to pri­or­it­ising the reduc­tion of energy con­sump­tion in freight trans­port as much as pos­sible, using the levers of sobri­ety (men­tioned in the first art­icle and detailed in the next two art­icles in the series). Both to decar­bon­ise the sec­tor quickly enough to meet the object­ives, but also to lim­it the fin­an­cial cost and oth­er envir­on­ment­al impacts of the transition.