United Airlines Chart a Course for Greener Skies with SAF

Is the sky the limit for sustainability or can we make even our most stratospheric activities green and clean?

This is a question that has long been asked of the aviation industry. As long as we've known commercial flight, we've known its issues.

Airlines contribute to 3% of global greenhouse gas emissions, thanks to around 37.8 million yearly flights producing around 800Mt of CO₂.

But is the carbon/convenience compromise something we should settle for? According to Nili Gilbert, Vice Chairwoman of Carbon Direct and Lauren Riley, CSO and Managing Director of Global Environmental Affairs at United Airlines, the answer is an emphatic no.

Instead, the industry should be investing heavily in R&D for sustainable aviation fuel, otherwise known as SAF.

As the aviation industry grapples with its environmental impact, SAF emerges as a crucial solution to reduce carbon emissions while maintaining global connectivity.

Nili and Lauren discussed the challenges and opportunities surrounding SAF in a live interview, offering audience members a peek behind the curtain of the airline elites, a small glimpse of the battle plans.

So what will the future of flight look like?

The promise of sustainable aviation fuel

Let's begin by looking into SAF. During the her interview with Nili, Lauren succinctly describes SAF as "an alternative to conventional jet fuel derived from waste and renewable feedstock, meaning it has up to 85% less carbon on a lifecycle basis".

This reduction is massive, so it's no wonder why SAF is such an attractive option for airlines seeking chasing net zero targets.

It's also one of the only carbon abatement strategies that the industry has to run with, so it's important that it's developed as soon as possible.

Lauren acknowledges this unique position that United and all other airlines are in, saying: “Whilst the 3% that aviation contributes to global emissions may not sound like a lot, what I anticipate happening is that number increasing as other industries decarbonise.

“We’re a ‘hard to evade’ industry, meaning we don’t yet have scalable solutions for flying.”

The current challenges to scaling SAF

Despite its potential, the current production of SAF is falling way short of industry requirements.

Nili points out that "if we look at the total production of sustainable aviation fuel last year relative to the amount of fuel that United alone uses annually, that the SAF share would be just 0.1% of your total usage".

Lauren confirmed this stark reality, adding: "In a given year, United consumes about four and a quarter billion gallons of fuel.

“Last year worldwide, 150 million gallons of SAF were produced".

In the grand scheme of things, the current state of SAF is little more than a small green shoot.

There's no need for despair just yet, though. This is just the beginning for SAF.

An aviation innovation explanation

Waste oils and fats

Currently, used cooking oil and waste fats serve as the primary feedstock for SAF production. However, Nili notes that "only 6-8% of total fuel needs will be able to be met by these waste oils," which suggests the need for additional sources.

Biomass and agricultural products

In the interview, Lauren discusses the potential of biomass, a fuel and energy source that has been in maturation for many years now.

"Whether that's municipal solid waste, corn sugarcane or other sources," she says, "we're able to collect a lot of that biomass and convert it through different technology pathways."

These sources could provide a more substantial supply of feedstock for SAF production.

Power-to-liquid technology

Both Nili and Lauren express a great deal of enthusiasm for power-to-liquid technology during their conversation.

"Power-to-liquid could create really what I see is a closed loop for aviation," Lauren says. "It pulls CO₂ out of the atmosphere. You convert that using a whole bunch of renewable power, green hydrogen and other stuff into a jet fuel that is lower carbon". 

Taking other measures in the meantime

The full maturation of SAF is still a long way away.

It may be decades before the best products or right supplies are available to sustain a truly sustainable aviation industry, so other measures must be taken in the meantime to reduce its environmental impact.

One simple solution is known as 'lightweighting'.

Essentially, this is all about reducing the weight of planes.

As Lauren explains: "The less you weigh, the less fuel you use. The less fuel you use, the less emissions you produce." #

Another involves a phenomenon called condensation trails, otherwise known as 'contrails'.

Contrails are the white, cloudy streaks that planes sometimes emit and they trap heat in the earth’s atmosphere and contribute to climate change.

They occur when a plane flies through part of the sky which has a different temperature, pressure or humidity than normal.

Avoiding these patches of sky could be rather simple, Lauren suggests. "It's got to be a system wide solution. We could feasibly have air traffic control and all operators working together so that we actually do solve the issue."

The role of policy and corporate partnerships

Nili and Lauren's discussion also highlights the crucial role of policy and corporate partnerships in advancing SAF adoption.

Lauren praises the US Inflation Reduction Act as "historic" in its support for sustainable aviation.

She also emphasiss the importance of corporate partnerships, noting that many companies "have their own climate commitments, some of them have budget assigned to really achieve those commitments".

Nili adds that these partnerships could help achieve economies of scale, potentially bringing down costs for all consumers in the future.

"With those actors paying up today, the vision is that we'll achieve the economies of scale that are required to bring the cost down for others," she explains.

Waiting for take-off

While the challenges are significant, both Nili and Lauren are optimistic about the future of sustainable aviation.

Lauren sums up the industry's stance: "We have the solution set, we just don't have the economics that line up to make it the preferred channel, the preferred path forward.

"We need to shift that paradigm so it becomes the preferred path forward".

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