Fuel made with used oil and more direct flights: the aviation plan to be more 'green' without electricity

Unlike other sectors, aviation cannot aspire to become electrified in the short and medium term and what appears in the long term is still a long way from maturing.

Thus, the 'green' alternative is the decarbonization of the sector, a plan that is sustained on four pillars.

And green hydrogen, of course, cements several of them.

The Ministry of Transport, Aena, AESA and the Airlines Association (ALA) signed an agreement on Wednesday to establish the Alliance for the Use of Green Hydrogen in Aviation.

"It is very important, but it is still a part of the roadmap as a whole,"

, president of ALA, explains to EL MUNDO.

One of these pillars are the operational improvements that, although they do not have to do with the process of flying, the movement of the engines, do with everything that surrounds this.

It occurs both on the ground and in the air.

It includes, for example, the use of solar panels at airports or electric aircraft assistance vehicles, instead of the traditional gasoline or diesel vehicles.

And it also affects how you fly, efficiency in the air.

Currently, each country controls its airspace, which means that

, but rather zigzag and follow a serpentine trajectory on the way to their destination.

"The single European sky, which we have been talking about for 20 years, could reduce around

", details Gándara. "What he basically seeks is for the trajectories to be as efficient as possible and to be able to fly as straight as possible."

Another of these pillars is technology, which in turn has two aspects: the already existing conventional one -and the ability to improve its efficiency- and the disruptive ones, such as hydrogen.

"Planes are becoming more efficient; an Airbus 320 emits 50% less CO2 than its equivalent from 30 years ago," Gándara contextualizes.

In the future, the gas that everyone is talking about could create an airplane with a propulsion source other than kerosene.

But a lot is missing.

"In the case of aviation, we are talking about the medium or long term, because, in addition, it is not only that it exists and that it is approved, but that it must be fully certified; safety on board is the first priority", details the manager. .

In addition, even if they arrived tomorrow, the useful life of the aircraft must also be taken into account -

- and the gradual renewal of the fleet.

There are also other challenges, such as the conditions necessary to maintain hydrogen in a vehicle in flight (it requires a very low temperature) or the differences with respect to kerosene.

The energy potential of this fuel per unit of mass -that is, per weight- is much lower, but per unit of volume -what it occupies- the opposite occurs.

Although in theory the plane will be able to take off more easily if it weighs less,

.

"The issue of how all that volume of hydrogen is going to be accommodated must be resolved," says Gándara.

This point of the roadmap is intertwined with the third, an already existing sustainable fuel (SAF, for its acronym in English).

It is not yet produced on a large scale, but current engines

, so they will be ready when it happens.

Europe, for its part, supports it and demands it, although aware of these limitations: the regulation of the FitFor55 plan dedicated to the sector, ReFuel Aviation, still has to be approved, but it will establish that minimum percentages will be mandatory at all airports in the European Union of SAF.

It will start with

.

Gándara appreciates the "legal certainty" that this will convey to producers, who will have a guaranteed minimum demand.

And, although that 2% may not seem ambitious, the manager contextualizes that in 2019 SAF production was equivalent to 0.1% of total kerosene consumption, which means multiplying it by 20.

olive fuel

There are, in any case, three types of sustainable fuel: two that use biological raw materials and a synthetic third.

The intertwining also occurs here, since the 'artificial' is created with hydrogen and carbon and when it is captured from the atmosphere it can reduce emissions by 100% during the life cycle.

In the biological ones, the percentage remains around 80%, but they add a recycling component, since

.

A few months ago, several planes left Seville airport with 4.5% fuel made from olive pits.

However, there are still pitfalls and the easiest to understand is the price.

"The price of SAF oscillates between three and six times that of conventional kerosene when it had a normal price," Gándara details.

All this would raise the costs of a sector in which

.

"That must be resolved, because it would be useless to have aircraft powered entirely by SAF, but then it would be so expensive that no one could afford to fly, only the very rich," he points out, before attacking other measures, such as the kerosene tax. , which he considers would also make the tickets more expensive.

However, he believes that the first goals set by FitFor55 give enough room to scale production.

"The challenge here is not just to make aviation sustainable, but to make it sustainable and remain affordable."

Everything that cannot be included in the three previous pillars, explains Gándara, forms a fourth pillar with market mechanisms -systems such as emission rights- and public policies.

And in any case, each company has its own roadmap: one that flies more long-haul will be more interested in SAF, which will have a more immediate impact on this, since hydrogen propulsion will start first on short flights.

electric planes

What does not seem to be going -precisely- to take off is

.

Although there are projects, batteries represent an impediment that is impossible to overcome with current technology: they occupy and weigh too much.

"At the moment, the most that is being achieved is to obtain prototypes of about nine seats and not for very long distances," explains Gándara, who illustrates the problem with an example.

"An A320-type plane without passengers and with tanks full of kerosene

," he details.

In the event that the same kilos of hydrogen could be put in as kerosene -remember that volume is different from mass-, that same plane could reach Australia.

"If we do the same exercise, same weight, but with electric batteries,

."

According to the criteria of The Trust Project

Know more

• Environment