Aviation continues to pose an ongoing headache when it comes to the climate crisis. With 65% of its emissions occurring in international airspace, the aviation industry is not included in the Paris Agreement, as no one country would take responsibility for reducing those emissions. Gladly, the International Air Transport Association has stepped up to the plate for sustainable development in aviation, pledging for the industry to go net zero by 2050.
But how does the aviation industry, a sector that has emitted more than 32.6 billion tonnes of CO2 since 1940, go green? Especially when half of that has been since 2000.
Well, as members of the aviation industry have raced to go (or at least appear) green, a key way of achieving this has been through carbon offsetting. The carbon emissions of the flight itself are not reduced, but companies will buy “carbon credits,” that support projects reducing carbon elsewhere.
On Tuesday, United Airlines announced a $100 million Sustainable Flight Fund for start-ups developing SAFs. Using investments from Air Canada, Boeing, JPMorgan Chase, Honeywell, and GE Aerospace, United seeks to support start-ups working on SAF research, production and technology.
Although the airline has purchased around 36 million litres of SAF since 2016, the total volume of the fossil fuel alternative it used constituted less than 0.1% of its total aviation fuel usage.
On February 16, DHL announced the launch of a service that allows UK customers using its international courier division, DHL Express, to choose to use SAF. Those who use DHL’s “GoGreen Plus,” can tailor how much SAF, sourced from BP and Neste, they wish to use in their shipping. Although this programme is currently only available to UK customers, DHL says it will become available globally in the coming months.
Through this roll-out, DHL appears to be following in the footsteps of private aviation company, Victor, which is known for its revolutionary 2019 200% carbon offset scheme. Although this move was heralded at the time, Victor caused a stir in January with its unexpected announcement that it was ending this programme.
Instead, the company appears to be focussing on its SAF scheme. This scheme allows customers to select up to 100% SAF for their journey, for only a marginally increased price. The customer’s purchase does not affect the fuel used in the specific flight they will travel on, but represents the amount of SAF Victor will purchase from Neste – a leading SAF producer – for use on future flights.
Unlike Victor, however, DHL currently has no plans to end GoGreen, its carbon offsetting programme.
What is SAF?
SAF isn’t one type of fuel, but rather encompasses a range of sustainable alternatives to traditional jet fuel. This can mean biofuels made from certain feedstocks (raw materials) or synthetic aviation fuels. SAF which meets industry standards has to prove that its physical and chemical characteristics are nearly identical to traditional jet fuel.
DHL is purchasing SAF from Neste and BP, both of which produce SAF made from used cooking oil and waste animal fat, some of which is sourced from McDonalds restaurants in the Netherlands. However, researchers are investigating further potential feedstocks for SAF including algae, household and business solid waste, lignocellulosics (dry plant matter), and renewable hydrogen.
How does SAF reduce emissions?
It’s worth noting that because SAF has to be nearly identical to fossil fuel, the emissions from burning both types of fuel are the same.
And these are not limited to C02 emissions. Although aviation accounts for 2.4% of the world’s carbon production, if we look at non carbon impacts, such as contrail cirrus (the line-shaped clouds produced by aircraft) and emission of nitrous oxides, we find that aviation accounts for 3.5% of present-day effective radiative forcing.
Effective radiative forcing, or ERF, is the imbalance in the Earth-atmosphere energy system since pre-industrial times, and is often used by scientists as a metric for climate change. Due to the fact that ERF enables comparison between various greenhouse gases (GHG) as well as other impacts that affect the climate system, it offers a much more accurate indicator of the sector’s “warming effect” rather than looking at carbon emissions alone.
Put like this, SAF seems very limited in the emissions that it cuts out in a flight. However, where it comes to shine isn’t in Scope 1 emissions, but in Scope 3.
But what do the different scopes mean?
The Greenhouse Gas Protocol laid out the “scopes” to account for the GHG emissions in any given sector.
Scope 1 is direct GHG emissions, i.e., those that occur from sources owned by the company. This includes emissions from combustion in owned or controlled boilers, furnaces, or vehicles, such as aircrafts.
Scope 2 is electricity indirect GHG emissions, i.e., the GHG emissions from the generation of electricity purchased by the company.
Scope 3 is a category for other indirect GHG emissions. For aviation, this is where the production of aviation fuel would fall.
So what puts the S in SAF? Curbing the emissions associated with fuel production, and using products that would otherwise go to landfill as feedstock.
Given the environmental impact of mining fossil fuels, this is no mean feat.
The world needs to reduce transport emissions and the amount of waste that cannot be recycled.
What if these problems resolved each other? 🗑️♻️
— Neste (@NesteGlobal) January 31, 2023
SAF is also remarkable in that it can be used in existing jet engines, so an airline, for example, doesn’t have to replace an entire fleet of aeroplanes in order to start using it, which would not only be slow and costly, but environmentally inefficient.
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However, currently, SAF is only approved to be used in blends of up to 50% with conventional aviation fuel. To put this into an industry context, DHL hopes to have blends of at least 30% in their air transport by 2030.
However, tests and research are underway to see if this could be upped to 100% SAF commercially at some point in the future.
One way to achieve this would be to blend two or more SAFs to create a fuel with characteristics suitable for 100% use in an engine. A second would be to adapt a current SAF production process to create a fully formulated SAF fuel in one process stream. The third option involves the investigation and development of new raw materials and processes that have not yet been approved.
In October 2021, the first in-flight study of a single-aisle aircraft running on unblended SAF was launched, and in March 2022, a ground engine test campaign was completed with the same fuel.
This year, on January 30, a short test flight of just under an hour, peaking at 32,000 ft, carried out by Emirates airlines, was the first test flight in Africa and the Middle East using 100% SAF.
And today, the first helicopter flight using 100% SAF took place in the UK.
Are people buying it?
Although SAF technology is advancing, SAF production is still limited, keeping costs high.
Because SAF incorporates a range of different fuels, determining exactly what the cost difference is compared to conventional jet fuel is a delicate matter.
Forbes found that a flight purchased from Victor using 100% SAF would mean an increased cost of 14% for the customer. However, IATA estimated that in 2021, SAF was two to four times more expensive than fossil jet fuels.
However, the demand is still there, as there are a number of airlines currently using SAF. On February 15, Boeing announced that it wanted to double its purchase of SAF from 2022, purchasing 21.2 million litres for 2023.
Time for a refill! ⛽
We're buying 5.6 million gallons (21.2 million liters) of @NesteGlobal blended sustainable aviation fuel for our U.S. commercial operations for 2023 – more than twice as much as last year.
— The Boeing Company (@Boeing) February 15, 2023
Neste plans to increase its production capacity for SAF to 15 times the amount by the end of 2023; from 100,000 tons to 1.5 million tons (more than 2 billion litres).
The market for SAF clearly exists, and provides an opportunity to reduce the aviation industry’s emissions in real time, rather than through carbon offsetting.
Is SAF enough to green the industry?
Despite some respite during the pandemic, the aviation industry is only expected to grow. The International Civilian Aviation Organisation predicts that demand for air transport will grow by 4.3% each year over the next two decades. In 2035, this will mean 200,000 flights taking off and landing every day.
While SAF is a serious step forward in significantly reducing aviation emissions, even blends of 100% SAF would be limited in the reductions they achieve, because Scope 1 emissions still remain untackled.
Despite the cautious optimism that SAF should inspire, it does not represent an alternative to curbing the demand for flights, and the necessary change required in human travel habits and behaviour.
Editor’s Note: The opinions expressed here by the authors are their own, not those of Impakter.com — In the Featured Photo: Aeroplane leaving contrails. Featured Photo Credit: William Hook.