Biofuels, an alternative that is still too expensive

Avi­a­tion is count­ing on the use of bio­fu­els and petrol-free syn­thet­ic fuels to reduce car­bon emis­sions. Tech­ni­cal­ly, it is pos­si­ble: “bio­fu­el stan­dards allow the incor­po­ra­tion of 30–50% biokerosene into cur­rent air­plane mod­els with­out mod­i­fy­ing the engine,” says Jean-Philippe Héraud, BioT­fu­eL project man­ag­er at IFP Éner­gies nou­velles (the for­mer French Petro­le­um Institute). 

How­ev­er, so-called first-gen­er­a­tion bio­fu­els made from food crops (grains or sug­ar) are not rec­om­mend­ed for use in sus­tain­abil­i­ty projects. They com­pete with the food indus­try and can have a neg­a­tive envi­ron­men­tal over­all when tak­ing into account the life cycle. How­ev­er, there is a place for sec­ond-gen­er­a­tion bio­fu­els made from for­est residues, straw and biosourced waste. 

Jean-Philippe Héraud says that “because France is a very green coun­try, the resources for these bio­fu­els exist. A major dif­fi­cul­ty, how­ev­er, comes from the mix of where the resources are locat­ed – as opposed to oil that arrives in France in only three ports. Hence, we need to know how to col­lect these wide­spread deposits and regroup the bio­mass so we can bet­ter trans­port it, whilst adapt­ing to sea­son­al vari­a­tions, too.” 

Hence, IFPEN has car­ried out research into the indi­rect ther­mo­chem­i­cal con­ver­sion of bio­mass. The bio­mass is gasi­fied to obtain a syn­thet­ic gas; a mix­ture of car­bon monox­ide (CO) and hydro­gen (H₂). After purifi­ca­tion, this gas is trans­formed into a syn­thet­ic paraf­fin using a process known as Fis­ch­er Trop­sch. “We have demon­strat­ed the fea­si­bil­i­ty of the BioT­fu­eL project, now we have to turn it into an indus­tri­al real­i­ty, » explains Jean-Philippe Héraud. 

The cost of this bio­fu­el is high­er than that of kerosone made from fos­sil fuels, “between 1.5 and 2 times high­er than equiv­a­lent fos­sil fuels before tax,” says Jean-Phillipe. “This extra cost varies accord­ing to the price of the raw mate­r­i­al, the loca­tion and inte­gra­tion with sites under­go­ing con­ver­sion.” And he says that this is their chal­lenge, “it seems dif­fi­cult to make air­line cus­tomers bear the bur­den with­out the risk of them turn­ing away from air transport.”

Fuel rep­re­sents about 25–30% of the price of a flight. “For a round trip from Paris to New York on an air­craft using 1% bio­fu­el, the price of the tick­et would increase by $5 per pas­sen­ger,” explains Paul Mannes, direc­tor of avi­a­tion at Total. “For a flight using 10% bio­fu­el, it’s ten times more, or about $50. So yes, the price could be a deterrent.”

It goes with­out say­ing that air­lines will not raise tick­et prices if they are not forced to do so. “The French gov­ern­ment is work­ing with the nation­al com­pa­nies con­cerned, such as Total, Air­bus and Safran, to see how the SAF (Sus­tain­able avi­a­tion fuel) indus­try could be devel­oped, and the nec­es­sary leg­is­la­tion,” he says. For the moment, the pro­jet des loi de finance includes an oblig­a­tion to use 1% bio­fu­els in 2022, 2% in 2025 and 5% by 2030, in order to keep pace with the increase in demand and the avail­abil­i­ty of SAF on the market.

French Ener­gy com­pa­ny, Engie, has launched a bio­mass pyro­gasi­fi­ca­tion project called Gaya. Wood is heat­ed to high tem­per­a­tures with very lit­tle oxy­gen, con­vert­ing it into a mix­ture of gas­es: hydro­gen, CO₂, methane, car­bon monox­ide, which are then reor­gan­ised to form fuel. But here again, the price is high.

The oth­er way to make fuel from non-oil-sourced sources are syn­thet­ic fuels derived from hydro­gen, which itself comes from elec­tric­i­ty. The prin­ci­ple: com­bine hydro­gen with CO₂ to obtain syn­thet­ic methane, the pre­cur­sor of oth­er fuels, called ekerosene. “We know how to pro­duce this ekerosene,” says Samuel Says­set, chief tech­ni­cal advi­sor at Engie. “South Africa, in par­tic­u­lar, devel­oped this know-how dur­ing Apartheid when there was an embar­go on petro­le­um prod­ucts. The main con­cern now is the eco­nom­ics of the sec­tor: ekerosene is more expensive.”