Energy and chemicals group Sasol, which recently secured product-sustainability certification for jet fuel and diesel produced from used cooking oil and vegetable oils at its Natref refinery, says any potential ramp-up to 200-million litres, or beyond, will now depend on market demand.

Business building, strategy and technology executive VP Sarushen Pillay tells Engineering News that an onsite audit by TÜV SÜD confirmed that Natref is able to produce products classifiable as a sustainable aviation fuel (SAF) and renewable diesel in line with International Sustainability and Carbon Certification, or ISCC+.

These certified fuels, which trade at a premium relative to traditional jet fuel and diesel, will be marketed to airliners facing tightening sustainable-fuel mandates, as well as mining, logistics and corporate entities seeking to reduce their carbon footprints.

“The concept now is to sell the SAF produced at Natref to global airliners that are seeking to claim carbon credits, and which refuel at the OR Tambo International Airport,” Pillay says.

He is also optimistic that its ‘drop-in’ renewable diesel could prove attractive to mining and other entities looking for new avenues to accelerate their decarbonisation over-and-above their ongoing transition to renewable electricity so as to reduce the exposure of their exports to carbon border levies.

The refinery in South Africa's Free State province has a nameplate capacity of 108 000 bl/d and Pillay says that, with no or low capital investment, up to 15% of that capacity could be deployed in future to produce hydroprocessed esters and fatty acids, or HEFA, fuels.

However, the initial ramp-up will be modest, with about two-million litres this year, 16-million litres next year and with the far higher production target planned for the end of the decade.

Asset transformation VP Vimal Bhimsan reports that the certification process confirmed the greenhouse-gas (GHG) intensity of SAF produced with used cooking oil to be 22 gCO₂eq/MJ, more than 75% lower than the 94 gCO₂eq/MJ associated with jet fuel from crude.

It also showed the GHG intensity of renewable diesel derived from used cooking oil to be 23 gCO₂eq/MJ, compared with 94 gCO₂eq/MJ for diesel derived from crude.

Bhimsan stresses that the certification also involves the measurement of the full value chain, including water use to grow the crops that may be employed in future, such as potentially using vegetable oil derived from Solaris and Moringa crops.

Sasol, Anglo American and De Beers are piloting the production of vegetable oils from Solaris and Moringa plantations on degraded mining land, while also using treated acid mine drainage.

The immediate focus at Natref, however, is on securing used cooking oil that is already being collected and aggregated domestically, but which is mostly being exported to Europe for reprocessing.

CHEMICALS CERTIFICATION
In addition, certain chemicals produced at Secunda using bioethanol as an input have also been certified, notably monomers that are used in downstream chemical products such as plastics, acrylates and solvents.

Sasol, which is looking to reduce Secunda’s massive carbon footprint, believes there is potential to source far more bioethanol from the South African sugar industry, which is in search of new sources of demand to provide a lifeline to a sector that is in distress.

Bhimsan acknowledges, though, that this will require a coordinated national effort to facilitate the investments that will be needed to upscale production.

Meanwhile, Sasol is also assessing the potential to buy some of the wood chips currently being exported through Richards Bay for use in its Secunda gasifiers to produce lower-carbon chemicals.

The JSE-listed group is also participating in the Hyshift Consortium that is aiming to produce SAF using green hydrogen in its existing Fischer-Tropsch reactors.

However, producing such power-to-liquid fuels as Secunda would not currently meet Europe’s Renewable Fuels of Non-Biological Origin compliance criteria.

These involve strict additionality and temporal matching rules for renewables generation and hydrogen production, which means that any green-hydrogen-derived SAF currently produced at Secunda cannot currently access the EU’s market that makes a minimum SAF blend mandatory. There are ongoing discussions between South Africa and the EU on integrating a flexible-allocation methodology in future, however.

Pillay indicates that the initiatives at both Natref and Secunda form part of a broader strategy to leverage existing assets as a springboard into future low-carbon markets, and rebuffs claims of possible ‘greenwashing’.

He argues that the certification process proves the fuel’s sustainability advantages over the traditional crude route, while highlighting the social, employment and community benefits associated with employing and/or repurposing existing assets.

“This project achieves all of that while also giving you a near 80% emission reduction. So, I believe it ticks all the boxes of a sustainable product,” he states.