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Etihad’s ‘Greenliner’ reveals a glimpse of a extra sustainable future for aviation

(CNN) Whereas some delegates eventually week’s COP27 local weather convention had been criticized for arriving by personal jet, others arrived in Egypt aboard flights that had been described as being emission-free, as they had been powered totally by sustainable aviation gasoline.

The flights had been a part of a program referred to as “Greenliner,” run by Etihad Airways, the nationwide service of the United Arab Emirates, as a testbed for sustainable air journey options.

Business aviation accounted for simply over 2% of world CO2 emissions in 2021, which suggests it could be a modest contributor to local weather change. However the quantity does not inform the entire story, as air journey impacts the local weather in additional advanced methods than simply carbon emissions, and its affect is predicted to rise sooner or later, as increasingly individuals will need to fly.
Whereas renewable power and electrical automobiles provide clear pathways to decarbonize sectors like energy and street transport, it is much less straight ahead for the aviation trade.
Because of this, the trade will not be on observe to satisfy its web zero goal by 2050, and is banking on two thirds of that transition coming from sustainable aviation gasoline (SAF). It is constituted of waste merchandise and might curb emissions by 80% on common — nevertheless it at present accounts for simply 1% of world jet gasoline utilization. One thing wants to vary, quick.

That is why SAF is likely one of the key parts of the “Greenliner” program. “It is basically a name to motion,” says Mariam AlQubaisi, head of sustainability at Etihad. “The thought took place in late 2019 to launch a message to the trade: let’s attempt every part doable to decarbonize.” This system is predicated across the Boeing 787 Dreamliner, however Etihad has an analogous initiative, referred to as Sustainable50, devoted to the Airbus A350. Since its launch, Greenliner has championed the adoption of SAF and tackled points akin to plastic waste and inefficient flight routes.

Etihad’s “Sustainable50” Airbus A350.


The “Greenliner” moniker is usually used to check with a particular 787 plane, which AlQubaisi calls this system’s “mascot.” Unsurprisingly, it is painted inexperienced — which she says is a strategy to pre-empt accusations of greenwashing.

“Any challenge any airline would launch will at all times be scrutinized below the umbrella of greenwashing,” she explains. “Portray the plane inexperienced was a strategy to problem that and say it’s devoted to a function. We’re proudly owning as much as our emissions: We’re saying sure, we’re a significant emitter — however we’re doing one thing about it .”

A fast repair

Etihad ferried delegates to Sharm El Sheikh in Egypt, the place COP27 passed off, by including a stopover to its common Washington Dulles to Abu Dhabi service. The flight was described as “emission-free” attributable to being powered fully by SAF — however confusingly, the planes truly used conventional jet gasoline.

The obvious absurdity highlights challenges with each SAF infrastructure and speaking inexperienced initiatives. The airplane did not have SAF on board as a result of present rules prohibit industrial flights from utilizing greater than 50% SAF, as not all engines are licensed for greater concentrations. Plus, not all airports have the infrastructure to make use of it, and the inexperienced gasoline should come from a manufacturing facility comparatively near the airport to keep away from canceling out the discount in flight emissions with these coming from transportation.

So, Etihad bought sufficient SAF to energy the flight and delivered the gasoline to Los Angeles Worldwide Airport, which has the mandatory infrastructure and services. There, the SAF was built-in into the airport’s refueling system with conventional gasoline, and utilized by whichever plane had been refueling that day. This technique known as “Guide & Declare,” and it is at present the one approach for a flight to assert it is utilizing 100% SAF. The emissions are merely offset elsewhere, relatively than on one particular flight.


Etihad’s “Greenliner” program assessments out sustainable initiatives on this Boeing 787 Dreamliner.


AlQubaisi calls it a “fast repair” till rules change, however for SAF to develop into extra widespread, extra progress is required. “The worth of SAF is 4 to 5 occasions that of typical jet gasoline and it is restricted in provide. Solely two our bodies are allowed to certify it, so till now we have extra and till governments intervene to incentivize manufacturing, SAF will proceed to be restricted, she says.

Etihad has used SAF extensively in a sequence of “EcoFlights,” which make use of the service’s 787 and A350 fleet to evaluate new sustainability initiatives. These culminated within the airline’s most environmentally pleasant flight ever, a London Heathrow to Abu Dhabi service on October 23, 2021. The flight, Etihad says, achieved a 72% general discount in emissions through the use of 38% SAF (by way of ‘Guide & Declare’ ‘) and adopted a number of different measures, akin to lowering single-use plastic by 80% and delivering baggage by way of electrical tractors.

It was additionally the primary industrial flight to check a novel strategy to fight emissions, through the use of navigation and synthetic intelligence to keep away from the formation of contrails. These are vapor trails that kind when ice crystals coalesce across the exhaust gases emitted by plane engines, and end in momentary clouds that lure warmth, contributing considerably to the warming impact of air journey. However modifying the airplane’s route or altitude may help dramatically. “The warming you are avoiding by merely including slightly extra time to the journey is as much as 60%, if no more,” says AlQubaisi. “What’s good about that is that it is carried out by way of particular algorithms that make the system develop into smarter the extra we use it.”

A greener future?

Etihad’s “EcoFlights” have trialed a variety of applied sciences and strategies geared toward lowering emissions, akin to an optimized climb and a steady descent, last-minute engine start-up, taxi procedures utilizing a single engine, and washing the engine with a particular foam that improves effectivity by lowering the build-up of deposits.


Sensible navigation may help to scale back a single flight’s carbon footprint.


Many of those strategies have since made it into on a regular basis operations, and in recognition of those efforts Etihad was named “Environmental Airline of the Yr 2022” on the annual Airline Rankings awards. In keeping with Geoffrey Thomas, Airline Rankings’ editor-in-chief, Etihad has proven “clear management within the push for sustainable flight.”

There’s nonetheless quite a bit to be carried out, AlQubaisi says: “That is an trade that has had free rein on air pollution for a few years and it is about time we come clean with our accountability to decarbonize.”

The important thing to reaching a greener aviation is everybody working in direction of it, she provides: “Hopefully you will hear of extra airways becoming a member of the Greener program, as a result of it does not matter who does it first — what issues is who does it higher.

“We are able to do higher collectively, as a result of sustainability will not be an space for competitors, it is an space for collaboration.”


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