Discovering Saf. What is sustainable jet fuel and how it works

Saf, which stands for Sustainable Aviation Fuel, or the alternative fuel (to classic kerosene) produced from industrial, vegetable and household waste that is to make aviation more sustainable. This is the fastest way to reduce the net Co2 emissions in aviation, but it does not mean that it is the most comfortable.

Why there is so much talk about Saf.

Despite this, the flight industry has made up its mind: the issue of sustainability can no longer be postponed and By 2050, the airlines have the goal of being carbon neutral, that is, cutting carbon dioxide emissions down to zero: that is, if all emissions cannot be cancelled, they should at least be offset.

To achieve this goal in time the only possible breakthrough, the immediate revolution, is to use Saf, pending the arrival of the electric and hydrogen-powered aircraft.

Aviation today is responsible for about 2.5% of global CO2 emissions, and the bulk of these (about 84%) are generated during the flight, while ground operations involving the airport and travel to it contribute 7%. If the near future is exciting, with aircraft manufacturers developing electric and hydrogen propulsion technologies (Airbus estimates that hydrogen flights will be a reality in 2035), high hopes in the short term are pinned on Saf.

The Saf helps reduce up to 80% of net emissions, and its big advantage is that it can be used on existing aircraft engines. There are two problems, however: the Saf costs much more than to jet fuel and its production is still limited.

The production node

According to the data Icao, in fact, a replacement of the 100% jet fuel with Saf could reduce emissions on all international flights by 63% by 2050, with the advantage that the fuel systems and engines of current aircraft do not have to be changed. "We are already using this fuel in some of our flights," said a few months Eleonore Tramus, general manager East Med of Air France-Klm - And we count on getting to 10% by 2030. But the problem is that of production: all the Saf produced in 2022 has been used, and it is arduous to increase production."

Apart from limited availability-nowadays less than 1% of requirements are used-the obstacles are both supply and demand incentives and costs, which for Saf are 6 and 7 times higher than normal (and fuel accounts for a quarter of an airline's expenses).

In addition to the "internal push" on the adoption of Saf, however, we also need to Incentivize the entire production, converting traditional refineries and bringing production and storage locations closer to major airports.

Here, then, the issue of alliances comes into play. Because if technological innovations will help reduce the emissions of players and suppliers in the entire industrial cycle, a renewed agreement among airlines-and between them and airports-could give momentum to the green turn.

The advantage of investing in Saf, as mentioned above, is that the engines produced today are already capable of operating on Saf's 50% compound blend. "The technology already exists and we are very close to being able to operate at 100% with Saf fuel. Now it is necessary to increase production and bring the storage and distribution locations to airport infrastructure," Air France-Klm ceo Benjamin Smith recalled during the recent Saf Masterclass organized by the Group.

The costs of transition

In fact, according to a study by the European Parliament, the purchase of aircraft with new technologies is expected to lead to additional costs (compared to current aircraft) of 378 billion between 2020 and 2050.

The report, titled "Investment Scenarios and Roadmaps for Achieving Aviation's Green Deal Goals by 2050," prepared by the Transport and Tourism Committee of the EU Parliament, stresses that of the total 378 billion, fifty would be allocated for research and development, but "the increased efficiency of the new aircraft will allow a fuel savings of 395 billion", the study points out.

So airlines have had to experiment with various solutions and partnerships to finance this so-called "green turn".

Airline choices

Each carrier, therefore, has launched proposals, ideas and initiatives to finance the transition to Saf. Among the many news stories related to the new fuel, we have selected some of the most significant ones.

United first launched an investment fund from 100 million dollarsi for the development of Saf together with businesses and consumers; and then announced that it will be able to power 50 thousand flights starting in 2028 with Saf.

In contrast, the Lufthansa Group introduced the Green Fares, fares that already include offsetting flight-related Co2 emissions, using Saf's 20% and contributing 80% to environmental protection projects.

Air France-Klm, among the Groups most active on the issue of sustainability, launched the Saf Corporate program. Project partner companies, after estimating the CO₂ emissions associated with their trips, can determine the annual contribution they wish to make. The group aims to increase Saf's share up to the 2% of total fuel in 2025 and reach 10% by 2030.

Ryanair, on the other hand, has partnered with Neste to power a third of the flights departing from theAmsterdam Airport with a Saf blend of 40% and has signed other such agreements with Repsol in Spain and Portugal. Ryanair's goal is to use Saf's 12.5% by 2030.

Wizz Air, finally, invested five million pounds in the biofuel company Firefly to provide Saf to its UK operations from 2028 (up to 525,000 tons over 15 years).

The role of Airbus

On the topic of ecological transition, Airbus has also recently scaled back its "hydrogen" ambitions, claiming that although the goals of a first-of-its-kind aircraft in the air by 2035 are realistic; currently the real paradigm shift can only be given by the use of Saf.

Airbus's deadline is right in the middle of the next decade, at which time it aims to begin introducing aircraft at zero emissions powered by hydrogen. Guillaume Faury stressed, however, that this means that "achieving the reduction of the 46% cannot depend on switching to hydrogen. You have to rely on the technologies that are there today, not on the big transition that will happen anyway in the second half of the next decade with the new generation of aircraft. So you have to rely for the most part on the use of the Saf, the sustainable fuel.".

Boeing's project

Boeing and Nasa , instead, have begun a collaboration to develop an experimental single-aisle aircraft that can reduce fuel consumption and emissions by up to 30% compared to state-of-the-art aircraft. In fact, the U.S. aerospace agency has selected Boeing to lead the development and flight test Of the experimental Transonic Truss-Braced Wing aircraft. (TTBW) on a large scale.

When combined with expected advances in propulsion systems, materials, and system architecture, a single-aisle aircraft with Ttbw configuration could reduce fuel consumption and the emissions up to 30% compared to today's more efficient single-aisle aircraft, not to mention the possible contribution of using Saf on the same aircraft.

The prototype of the plane, unveiled last January, provides for ultrathin wings supported by struts, with wider spans that could eventually accommodate advanced propulsion systems that are limited by the lack of space under the wing in today's low-wing aircraft configurations. For the demonstration aircraft, Boeing will use. elements of existing aircraft and supplement them with completely new components.

In addition, Boeing has committed to the purchase of 2 million gallons (7.6 million liters) of Saf for commercial aircraft operations and to reach 35% of companywide renewable electricity use in 2022 with renewable energy purchases and renewable energy credits.

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