Aviation without CO2: forget the electric plane, the solution is elsewhere, says Safran

For the aeronautical group, the objective of reducing emissions by 50% in 2050 compared to 2005 (despite the increase in traffic) is achievable. But its realization will not go through 100% electric airplanes, but through the combination of several factors: the entry into service around 2035 of new ultra-efficient airplanes with thermal engines, the generalization of alternative fuels combining biofuels and synthetic fuels , and improving operations management. However, there are many obstacles.

The abolition of short-distance flights and the race for an electric plane will never, according to the French aeronautical group Safran, allow to reduce in 2050 the CO2 emissions generated by aviation by 50% compared to 2005, as the set the International Civil Aviation Organization (ICAO).
Electric batteries are insufficiently powerful

In the absence of sufficiently powerful electric batteries, electric or hybrid planes will certainly be able to fly over maximum distances of 500 km very small capacity flying machines such as VTOLs (vertical take-off vehicles), and commute planes from 10-20 seats (or possibly regional aircraft), but they will never be able to fly 200-seat aircraft over 1,000 kilometers by 2035, a step that Safran says is necessary to make a significant gain in terms of fuel consumption and reach 2050 targets.

"On this type of planes and distances, there will certainly be hybridization with electricity which will arrive to the internal combustion engines, but to replace internal combustion engines by electric motors, it is necessary to forget. We were fooled by this happening in the automotive sector, but the electric battery does not meet the demands of commercial aviation ", said last week to the press the general manager of Safran, Philippe Petitcolin.

Electric batteries, which today have a power of 200 watt-hours per kilogram [Wh / kg], are too weak. And battery specialists have no solutions in the boxes.

"To fly an A320 which carries 80 tonnes of charge on journeys of up to 5 hours, you would need to take 180 tonnes of batteries which are 5 times more energy than those we know how to do today and which are beyond the scientists' roadmap, "explains Stéphane Cueillé, director of innovation and R&T at Safran.

Flights over 1000 km account for 80% of aviation emissions

However, dealing with the problem of flights over 1000 km is the sine qua none condition for achieving the objectives set. They represent 80% of global C02 emissions and cannot, most often, be replaced by other modes of transport. And will never be fitted with 100% electric motors by 2050, and even less in 2035.

Safran clearly wishes to share this observation with as many people as possible. History of not being dragged on false roads.

"We need to work on what has an impact on CO2 and not on what gives the impression that we are working. This is important. Because if the politicians ask us to work on the wrong subjects, collectively we don't solve the problem, "explains Stéphane Cueillé.

“The objective is achievable, we have a credible solution”

On the other hand, if Safran dismisses the electric plane for flights of more than 1000 km, the aeronautical group does not say that the objective of reducing CO2 emissions by 50% in 2050 compared to 2005 is not achievable. Quite the contrary.

"For us, it's playable. A few months ago, we weren't sure. Today, we think we have a solution that is credible. We looked at each of the blocks and they are all playable. Is "It is won in advance, of course not. But if we do that, yes we have a very good chance of getting there," says Philippe Petitcolin.

So what is this quick fix that will not go through an electric motor? In fact, there is not a single solution, but the combination of several levers. Exactly three: the entry into service around 2035 of a new ultra-efficient short and medium-haul aircraft; the development of alternative fuels, first of all biofuels, then of synthetic fuels, all compatible with thermal engines; and optimized flight operations management. If this last point alone can reduce CO2 emissions by 10%, or even by 20% if measures to reduce the speed of aircraft are decided, fleet renewal could mean a gain of 50% and new ones. 40% fuels.
Skip a generation of aircraft

These new aircraft in rupture will be those which will succeed the A320 Neo and B737 MAX. For Safran, they will have to “skip a generation”. That is to say, they will have to make a consumption gain twice greater than that generally observed when replacing a new plane with another (15%).

"We must make 30 to 40% gain. If, in 2035, we manage to generalize on all market segments of aircraft that make at least 30% fuel consumption savings, we will manage to stabilize CO2 emissions" , explains Stéphane Cueillé, specifying that "the engine, even if it will bring a large part of the hoped-for gains, will not be able to bring the totality. Result:" The aircraft manufacturers must play the game, ie they take risks "to improve aerodynamics in particular and the optimization of seating capacity.

The debate between traditional architectures with a fuselage and engines under the wings and architectures in rupture like the introduction of “open rotor” engines, located at the rear of the plane continues. If aircraft manufacturers have not been very hot lately with the concept of “open rotor”, the increased environmental pressure can put this type of engine on the top of the pile. The “open rotor” could indeed bring a gain of 15% compared to the “Leap” engine which equips the A320 Neo and the B737 MAX, and be available around 2035, according to Philippe Petitcolin. But “all options are on the table,” nonetheless points out Stéphane Cueillé.

“Freeze technologies within 5 to 7 years”

According to the latter, to be ready in 2035, “the technologies must be frozen within 5 to 7 years to launch the development phase”. In any case, this new aircraft will necessarily go, according to Philippe Petitcolin, through a deepening of relations between aircraft manufacturers and engine manufacturers.

Above all, the objective is to define a production system which makes it possible to lower the production costs of this aircraft, which will necessarily be more expensive than an aircraft which would not have required a generation jump, in order to introduce ” iso costs “a lot of technologies that will allow companies to make operational gains and absorb increases in fuel costs or the cost of CO2.
More expensive fuels

Because, to halve CO2 emissions in 2050 compared to 2005, this new aircraft will need a “green” fuel, which will necessarily be more expensive than kerosene today. For Safran, part of these new fuels will have to come from biofuels. Because of their very high cost (they are 2 to 3 times more expensive), they are almost non-existent today in aviation. They only represent 0.1% of companies’ fuel consumption.

"Today, 90 million tonnes of biofuels are produced worldwide for different uses, mainly for the automobile. In 2035-2040, when land transport has migrated to suitable solutions, It is not delusional to imagine that the biomass is oriented for sectors that need it, "explains Stéphane Cueillé, specifying that this" biomass must be sustainable ", as can be waste, used oils, ...

But, even if such a transfer were to take place, it would not cover all the needs of air transport by this deadline.

"We believe that alternative fuels can take over," says Stéphane Cueillé.

For him, two paths emerge: the first consists in using green synthetic fuels, which are in fact solutions based on green hydrogen (or Power to liquid). Concretely, by combining hydrogen with CO2, we obtain kerosene, without biomass, usable as fuel. CO2 could come from the industries that generate it or be captured in the atmosphere. In Safran’s eyes, this is the simplest solution. It would also have the advantage of being able to be introduced up to 75% in a mixture with kerosene, or even more than 90% without “enormous R&T efforts”.

However, if this technology does not succeed, there remains, according to Safran, another solution, much more complex: using hydrogen as it is. This option, which could only be considered after 2040, would constitute a “huge” leap. Specific planes are needed, which are larger to carry very large cryogenic tanks necessary to store liquid hydrogen 2 to 3 times larger than kerosene.

Many uncertainties

Ultimately, Safran’s road map is indeed on paper. But it nevertheless presupposes a perfect alignment of the planets. However, serious obstacles exist. First of all, the hopes raised on sustainable fuels and synthetic fuels are conditioned to political support to set up a sector, first of biofuels, then of green hydrogen, for aviation. Such a sector will only be able to emerge if there is a demand for such fuels. For this, there must be an incorporation obligation for the airlines. Problem, in view of the international specificity of air transport, such regulation can only be done on a global scale, on pain of creating competitiveness gaps between the companies which would be forced to use much more expensive alternative fuels and those who would not be forced to. Given the slowness of the discussions to set up in pain the global compensation system for Corsia CO2 emissions from 2020, it now seems illusory to hope to bring all the countries of the planet together on such a project.

"Ideally, it should be at ICAO. At least in Europe", explains Stéphane Cueillé. "Europe must be in a position of influence and not be in breach with certain countries," he adds.

What if Boeing will soon launch the successor to the 737 MAX?

Another unknown that could disrupt the scenario of Safran. The launch date of the successor program for the A320 Neo and the B737 MAX. To reach the objective, these new planes would have to arrive on the market in 2035. Today is roughly the Airbus calendar. Recently its managing director, Guillaume Faury, indicated that he expected a launch in the middle of the next decade for entry into service in the early 2030s. Until the B737 MAX crisis, this calendar was also that of Boeing. The commercial success of the A320 NEO and the Boeing 737 MAX made it possible to reduce the need to launch their successor. And therefore to allow time for technologies to mature.

Today, with the B737 MAX crisis, there is a doubt. A new problem or a persistent boycott of the aircraft after its return to service could indeed push Boeing to quickly launch a new plane as feared by Philippe Petitcolin. A decision that would likely push Airbus to follow within two years, he said. However, the launch of a new program in 2022 for entry into service in 2027-2030 will not achieve the objectives of reducing expected fuel consumption. A plane launched so early could only gain 5%. Because the new technology engines will not be ready at that time. And given the sums involved and the lifespan of the planes, there would be no chance, of course, of seeing the aircraft manufacturers relaunch an aircraft in the process that is available by 2035.

In this scenario, the setbacks of the B737 MAX would lead to the failure to achieve the emission reduction targets set for 2050.

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