Numbers don’t lie, as the saying goes, but like anything else, they can be misleading when taken out of context. A figure like 2 percent, for instance, is seemingly small. It also happens to be the carbon emissions produced by the aviation industry as a percentage of all human-induced CO2. In tonnage, that translates into 915 million – the amount global aviation was responsible for in 2019 when it transported 4.5 billion passengers, according to the Air Transport Action Group.

By 2050, however, when traffic is expected to have more than doubled, with 10 billion passengers choosing to travel by plane, that figure could shoot up to as high as 22 percent – or 1.9 billion tons of CO2 – if no efforts are made to decarbonise.

While awareness around climate change has grown and continues to do so – from individuals’ “flight shame” to companies cutting back on business travel as they try to limit their carbon footprint – the desire for air travel continues unabated, as was witnessed last summer when traffic returned to 70 percent of 2019 levels as soon as covid-related travel restrictions eased.

But aside from the sector’s social impact – connectivity – its economic impact also cannot be overlooked. According to ATAG, if aviation was a country, it would rank 17th in the world, generating $961.3 billion of GDP per year.

Given aviation’s social and economic significance then, the solution doesn’t lie in stunting its growth, but finding ways to make it less polluting.

From the ground up airports, which many of the infrastructure fund managers Infrastructure Investor spoke with for this story described as being at the “core of this ecosystem”, can serve as a catalyst for the sector’s needed transformation.

The first place to start is with airports’ Scope 1 and Scope 2 emissions. The first category includes things such as vehicles, ground support equipment, onsite waste and wastewater management, onsite power generation, boilers and furnaces. The second comprises electricity purchased, heating, cooling and lighting.

“Everything that’s related to fleets of vehicles that we use for maintenance, for baggage handling, we are progressively converting to electric vehicles at all our airports,” says Romain Limouzin, deputy COO, Europe at Meridiam, which is invested in New York’s LaGuardia Airport; Queen Alia International Airport in Amman, Jordan; Sofia Airport in Bulgaria; and Ivato and Nosy Be airports in Madagascar. The Paris-based firm is also aiming to bring renewable energy production onsite at all its airports.

Electrification of ground equipment is an initiative other GPs we spoke with are also implementing at their respective airports, and are at various stages of completion.

Aside from being the first place to start, Scope 1 and 2 are also the easier emissions for airports to tackle as they are generated by activities/operations that fall under airports’ direct control.

Sphere of influence

Scope 3 emissions, on the other hand, which have the biggest impact – accounting for more than 90 percent of airports’ carbon emissions – are not under these assets’ direct control. They are, however, within their sphere of influence.

The first step is to be able to measure and monitor those emissions, something Ardian set out to do when it began developing digital tool Air Carbon.

“The reason we built [Air Carbon] and the reason we focused on Scope 3 emissions is because Scope 1 and 2 are generally well covered now by ready-to-use software,” Pauline Thomson, director and head of digital innovation at the Paris-based firm, says. “Scope 3 emissions for airports is particularly tricky because you have a lot of stakeholders involved in data on landing and take-off of airplanes; data on ground-handling; on the use of auxiliary power units by airlines; on passengers commuting to the airport. It’s a lot of different data sources that need to interact together.”

Air Carbon, which Ardian is using at all its airports – Milan’s Malpensa and Linate, Naples and Turin – is able to not only measure carbon emissions in real time but to forecast up to 10 years ahead the gains in carbon reductions measures taken today could generate.

Speaking of measures that can be taken today, there are several, one of which is what Thierry Cojan, principal at Brisbane-headquartered QIC calls “green landings”.

“Typically, you seek to have a shorter and steeper approach [of the airplane], which means you have less low altitude flight time,” he explains.

Optimising landing trajectories is a process that is implemented after consultation between the airport, the airlines, local communities and the air traffic management system “to understand what flight paths can be operated, when it can be implemented and ensuring that the relevant safety and operating procedures are in place to act upon that”, Cojan adds.

At Brussels Airport, which along with Brisbane and Hobart airports, is backed by QIC, around 70 percent of landings, on an annual basis, are “green landings”, according to the airport’s website. Also known as continuous descent operations, they are called green landings because they generate less noise pollution, consume less fuel and emit less greenhouse gas emissions.

Naples Airport is also working on optimising landing and take-off routes. “It’s also something we want to be able to measure through Air Carbon – the emissions gained through that,” Thomson comments.

Taxi service

Another function that lends itself to significant carbon emissions reduction is the taxiing of aircraft to and from the gate. According to OAG, a data provider for a number of industries including aviation, anywhere between 2-17 percent of an airplane’s fuel is consumed during taxiing. That represents around 28 percent of airports’ Scope 3 emissions, Ardian states in its recent study, The Fight for a Net-Zero Aviation.

One solution is replacing the APU airplanes typically use during this part of their operation with electric tugs.

An example of this type of equipment is the TaxiBot. A semi-autonomous robotic vehicle that is powered by electricity, it was developed in collaboration with IAI, Airbus and Alvest subsidiary TLD. Used by Schiphol Airport in Amsterdam since 2020, it is said to cut CO2 emissions during taxiing by 85 percent and reduce noise pollution by 60 percent, since it enables the aircraft to move without running its engines.

Still, this is not a decision that falls to airports. But they can provide incentives to airlines to use them, in the same way they encourage airlines to renew their fleet by providing preferential tariffs on taxi time at airports.

Milan’s Malpensa and Linate airports already have such incentives in place, Edouard Bertagna, senior investment manager at Ardian, says. “There are incentives currently linked with noise reduction as in practice, the latest generation of aircrafts are quieter and emit about 20-25 percent less CO2 than their predecessors,” he explains.

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Fueling sustainability

Despite this improvement – CO2 emissions per passenger have declined by 25 percent over the past 15 years – global emissions from international aviation have still more than doubled since 1990, according to Ardian’s study.

The main culprit is the kerosene used, which accounts for roughly 95 percent of an airplane’s carbon emissions during its lifecycle. Finding alternatives to kerosene would therefore have the biggest impact on cutting carbon emissions in aviation.

That’s where sustainable aviation fuels come in. Produced from sustainable feedstock – either waste or biomass – SAF has the potential to reduce aircraft carbon emissions by up to 80 percent. While sustainable fuels emit as much carbon as traditional fuels when burned, the carbon reduction is achieved at the production stage.

The problem, however, is that there is not enough SAF being produced to meet the industry’s decarbonisation needs. Around 330 million tons of SAF will be needed if the aviation industry is to reach net zero by 2050. That’s a huge jump from the 120,000 tons produced in 2021.

“We believe [the aviation industry] started a bit too late,” says Bogdan Avramuta, market analyst for hydrogen, wind and aviation at Rethink Technology Research.

“There’s enough biomass, organic matter that can be transformed into SAF, so that’s not a problem,” he adds. “A plan with the agricultural industry should have been put in place and that never really happened. That’s why we don’t believe SAF will scale up to what everybody wants it to be.”

Avramuta’s criticism is not misplaced considering that the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) – the aviation industry’s first commitment to curb CO2 emissions, signed in 2016 – would only begin to be implemented (pilot phase) on a voluntary basis between 2021 and 2023. The first phase, which is set to be implemented between 2024 and 2026 is also voluntary. It isn’t until 2027, when the second phase begins, that it will become mandatory.

Still, the infrastructure GPs we spoke to are not giving up on sustainable fuels. “While SAF production is not a core competency of the airport, it’s crucial for the airport to be ready,” QIC’s Cojan remarks. “What it all comes down to is making sure that the infrastructure is in place; the investments, if necessary, are identified; and that ultimately, as a partnership with the end users, there is agreement on driving that forward.”

Meridiam’s Limouzin also points to a collaborative approach. “Our teams on the ground at our different airports are already co-operating closely with the airlines. For example, we’ve launched a number of studies for sustainable aviation fuels and are currently comparing different types of new fuels – biofuels, synthetic fuels, hydrogen.

“We are consulting with experts to understand the feasibility of each of the options, their potential future uses and the most effective ones. So, that’s something we’re already doing because we believe it will come and we definitely want to be at the forefront of that.”

Sustainable aviation fuels are en route. According to Karine Guenan, vice-president, ZEROe H2 Ecosystem at Airbus, all of the manufacturer’s aircraft are certified to operate on 50 percent SAF. The company is committed to “bring by the end of the decade the capability to blend up to 100 percent on our existing aircraft models”, she said, speaking at a conference on aviation hosted by Ardian last November.

And the infrastructure required to accommodate this transition already exists at airports. As Avramuta explains: “From the point where you have liquid SAF in the tank to fuelling the airplane, the infrastructure is already in place because it’s the same as that needed for kerosene.”

Intermodality in the interim

But while the industry waits for production of SAF to scale up, there are other actions it can take in the meantime.These include, but are not limited to, using electric vertical take-off and landing aircraft (eVTOL) for first- and last-mile travel to and from the airport for passengers and staff. Last November, Groupe ADP inaugurated the first vertiport in Paris. Developed by Skyports, it will serve as a “testbed for future electric vertical take-off and landing”, ADP said in a statement.

Aside from decarbonisation, urban air mobility can also provide airports with a new revenue stream.

Linate Airport offers a good example of combining those two elements. The airport’s operator, SEA Group, which also operates Malpensa Airport, collaborated with the city of Milan and other partners to develop the Linate Airport metro station, which opened in November. The new link is expected to attract not only air travellers but also residents in the surrounding region who work in Milan’s city centre, so, SEA Group has built a new car park that will serve commuters. The airport has also partnered with local authorities, installing super-fast EV charging stations powered by renewable energy.

“Basically [commuters’] trip to work will be sustainable and we will be making revenues from parking and from recharging electrical cars and there will be no flights involved,” SEA Group chief executive Armando Brunini told the Ardian conference. “So, we see intermodality going beyond just aviation.”

The various shifts related to the sector’s decarbonisation, including intermodality, will also come down to customer expectations and preferences, QIC’s Cojan says.

“This ultimately enhances the ‘social licence to fly’ for airports, and for investors in airports,” he comments. “So, it’s really about driving the right outcome for the community, which will include the airport’s local community, but also on a wider scale, the region, the country and the global environment.”