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.”