May 20, 2024

A beginner’s guide to SAF

It could help propel the aviation sector towards its emissions targets but there's still some way to go. Gary Noakes answers some of the key questions

What is Sustainable Aviation Fuel?

A good question! There are three types, but arguably only one that’s truly sustainable.

SAF can be produced from household and industrial waste that would otherwise go to landfill. While this avoids the use of kerosene it does still emit greenhouse gases and often uses a recyclable resource like plastic waste.

Biofuels, produced from crops like rapeseed, are another form of SAF, but are land-intensive and prioritise fuel over food. The use of farm machinery, pesticides and transporting the raw material must also be factored in. However, when the plants are growing they absorb Carbon Dioxide (CO2)

A third type is derived from hydrogen and captured carbon, literally plucked from the air. This process uses water and renewable electricity, like wind power, to refine hydrocarbons into liquid fuel. It sounds unbelievable, but KLM has already powered a flight to Madrid with fuel produced by Shell based on CO2, water and renewable energy from sun and wind.

Why should corporates know about it?

SAF is important because it’s one way of making business travel more sustainable and should be on any corporate’s social responsibility agenda. Electric aircraft will never replace jet-powered over long distances, so SAF’s development as an alternative to kerosene must be encouraged.

What difference does it make?

Currently, SAF is making very little difference: at present it’s only 0.1% of total industry usage, but supply is ramping up.

SAF has a much cleaner ‘burn’ compared to conventional kerosene, with one carrier estimating a near 80% reduction in greenhouse gases, particularly CO2. In the case of plant-based fuels, CO2 absorbed by plants during their lifecycle is roughly equivalent to the amount of carbon dioxide produced when the fuel is burned, unlike fossil fuel. In addition, particulate matter is reduced by around 90% and sulphur by 100%.

Why is it not widely used yet?

Simply because there isn’t enough of it, which also makes SAF more expensive than kerosene. The premium paid for SAF varies from at least double the cost of kerosene to five times more depending on the source and location. The Environmental Protection Agency estimates just over 2.4 million gallons of 100% SAF were produced in the US in 2019, compared to 21.5 billion gallons of conventional kerosene used by US airlines, making SAF only 0.01% of the nation’s total jet fuel supply. The picture is similar or worse in other countries.

How are airlines using SAF?

Airlines are only currently permitted to use 50% SAF blend. In December, United Airlines claimed an industry first after it flew a Boeing 737 from Chicago to Washington with one engine run entirely on SAF and another on conventional kerosene. Longer term, aircraft will be delivered with SAF modifications as standard, but until then, blends will be used.

Will it get less expensive over time?

Yes, simple economics tells you that as supply increases the price will drop. And airlines are keen to encourage production. In January, Air France/KLM introduced a SAF levy of €1-€12 on departures from France and the Netherlands. The levy will finance the 0.5% SAF being added to KLM’s fuel mix.

Who is leading the way?

United Airlines, KLM, British Airways and Virgin Atlantic are among those beginning to use SAF and encourage production.

In December, United, which has pledged to be carbon neutral by 2050 without any carbon offsetting, committed to purchasing 7.1 million gallons of SAF – almost twice all current global airline SAF commitments.

United’s efforts are laudable but the scale of the challenge is apparent when you consider the carrier consumes four billion gallons of conventional jet fuel a year. United signed a deal in March with Houston’s Cemvita to produce SAF from CO2 and synthetic microbes, another process of taking CO2 from the air and producing a low carbon fuel.

KLM is in a partnership to build a commercial synthetic SAF factory at Amsterdam port, while Britsh Airways has taken its first deliveries of SAF produced in Humberside from used cooking oil. The Phillips 66 Humber refinery is currently processing nearly half a million litres a day and the airline’s contract is enough to power 700 net zero CO2 emissions flights between London and New York on a Boeing 787 – roughly nine weeks’ flying given its 11 flights a day.

Virgin Atlantic will use 2,000 metric tonnes (440,000 gallons) of SAF, due to be delivered to Heathrow in the first half of 2022.

What else is aviation investing in to cut its carbon footprint?

United is also funding Direct Air Capture technology that removes CO2 from the air and buries it. The first plant in the US is planned to capture and store one million metric tons of CO2, equivalent to 40 million trees. Technology like this can be added to an airline’s carbon offsetting programme.

Is SAF the answer?

It’s the biggest part of the solution along with hydrogen and electric power, once this is developed for short-haul flights. There are other ways to chip at the edges, for example continuous descents instead of stepped descents, single-engine taxiing and more accurate wind and weather data to permit better flight planning.

How are TMCs getting involved?

TMCs recognise SAF must be a big part of their sustainability approach. TripActions and its sister TMC, Reed & Mackay, have signed a partnership with Neste to offer SAF to all clients. The fuel is unlikely to be used on actual flights taken but is purchased as an offset.

The pair identify the volume of CO2 produced by the client, allowing Neste to quantify the SAF required to meet the client’s CO2 reduction goals. Fuel is then delivered “to the appropriate location” for use, audited by a third party.

A spokesman for Reed & Mackay said: “SAF is, broadly speaking, four times more expensive than jet kerosene, but specific costs for individual clients will vary.”

American Express GBT has a similar partnership with Shell Aviation. The idea is that by encouraging clients to purchase SAF, the premium paid can be invested and production increased.

Si-Yeon Kim, Amex GBT Chief Risk and Compliance Officer, said corporate investment in credible carbon offsets and SAF can restore consumer confidence and trust in the intrinsic value of travel. “Now is the opportune time to capitalise on these opportunities so that we can solve this together,” she added.