A SAF future could be being built on an uncertain foundation

Photo: © Toa555

Tomorrow, in advance of COP28, a B787 will take off from London Heathrow and make what is otherwise a routine journey to New York, on Sustainable Aviation Fuel (SAF) alone.

What the scientists, politicians and media expect to learn about the fuel from their seats in the cabin remains to be seen. A great deal of hope, though, is going into the proof-of-concept; hope the flight’s specific CO2 emissions really can be reduced by 70%; hope there will be sufficient SAF available to make a substantial dent in the footprint of transport’s proportionately highest-polluting sector; and hope among airlines that SAF will allow them to continue ferrying influencers around the globe guilt-free, while changing nothing about their business model, save a bump in ticket prices.

But SAF’s biggest problem is one it shares with carbon capture and storage (CCS): it doesn’t really exist.

One of the world’s largest exporters of SAF feedstocks, Malaysia, also happens to be the world capital of virgin palm oil production. The implications of clearing carbon-breathing forests to make way for palm oil plantations is incredibly challenging to quantify; however, Transport & Environment (T&E) believes it has succeeded, finding that the net well-to-wake effect to be around three times as CO2-intensive as fossil diesel.

In 2020, Malaysia reclaimed just 70 million litres of used cooking oil (UCO), but still managed to export more than double that, 151m litres, to the UK and Ireland alone. The restaurants of Malaysia must be doing a whole lot of cooking. This year, UK airlines alone had bought some 18m litres of Malaysian UCO by the start of November.

The International Air Transport Association (IATA) calls upon governments to do more to make SAF available.

“Despite unequivocal demand signals, the SAF production market is not developing fast enough,” said Willie Walsh, IATA’s director general. “We need SAF everywhere in the world, and to that end the right supportive policies – policies that can stimulate production, promote competition, foster innovation, and attract financing – must be put in place today.”

In fact, governments are already attempting this. The text of the RefuelEU Maritime regulation, for example, contains provisions designed to discourage “a shift of crop-based biofuels… to maritime transport” for other modes.

“It is therefore appropriate to avoid the creation of a potentially large demand for food and feed crop-based biofuels, bioliquids and biomass fuels [in shipping] by promoting their use under this regulation,” said the EC.

There is good reason to doubt whether enough SAF could ever be provided. Recent research published by The Royal Society found that, to cover the 12.3m tonnes of fuel demanded annually by airlines in the UK alone, as much as 68% of British agricultural land would have to be devoted to biofuel production – depending on the crop.

As airlines well know, there are partial fixes available, such as that posited by Adel Ahmed Al Redha, COO of Emirates Airlines: larger aircraft, taking off less often and with far more seats. Likewise, a new iteration of the double-decker airline seat idea is trotted out on social media each year, to a fresh chorus of fart jokes.

In the case of air cargo, other fixes might be available – with no need to pressurise cargo, we could see radical changes to the footprint of aircraft, or new ‘flying wing’ designs.

As one study by the Aviation Environment Foundation notes: “The window of time for effective climate action is getting smaller by the day. Flights taking off now will generate CO2 which could remain in the atmosphere for hundreds, if not thousands, of years. We don’t have time to risk carbon accounting mistakes.”

As government and business functionaries convene in Dubai for COP28 – from Thursday until 12 December – its climate aims look, already, to be as least as much of a patchwork as UCO supply chains and there is a risk that more harm than good could come from expanding the use of what is called ‘SAF’.