At the recent Farnborough International Airshow, in England, US-based global major aerospace group Boeing unveiled a new tool to model data, which it designated Cascade, which was created to map the ways that the global commercial aviation sector could reach the international target of having net-zero carbon emissions by 2050.

“There are multiple ways to a future where aviation has zero climate impact,” noted Boeing chief sustainability officer Chris Raymond at the launch of the tool. “We created Cascade on a foundation of credible data and analytical models to allow users to explore various pathways to net zero.”

Different options to provide energy for aircraft propulsion, while significantly reducing or even eliminating carbon emissions, exist. The main ones are hydrogen, electricity (either pure or hybrid technologies) and sustainable aviation fuels (SAF).

“We have to take a holistic view to decarbonisation,” he pointed out. “And when we do that, it is clear that [SAF] is a necessary lever. We know it will take a ‘SAF and’ approach and not a ‘SAF or’ approach to achieving net zero by 2050.”

“Hydrogen and/or electric propulsion systems will most likely be available for short-haul commercial flights by 2035, but the majority of emissions come from long-haul widebody flights and to tackle these emissions, SAF is the only proven solution,” observed International Air Transport Association (IATA) senior VP: environment and sustainability Sebastian Mikosz at the body’s annual general meeting in June. “We know it works, and we need to double down our efforts to get all actors of the industry on board, including governments, to increase production, availability and uptake.”

SAFs are very similar in their chemistries to fossil fuels, but they are produced from sustainable feedstocks. These feedstocks can be rapidly growing plants (called energy crops), forestry waste, food scraps, animal waste fat, used cooking oil, and solid waste from businesses and homes, including paper, packing and textiles, or a mixture of these. Air bp, for example, makes its SAF from used cooking oil and animal waste fat.

All the major commercial airliner manufacturing companies (in alphabetical order, Airbus, Boeing and Embraer) and aeroengine companies (CFM International, GE, Pratt & Whitney and Rolls-Royce) have worked to make their products compatible with SAF. Most, if not all, have successfully flown their aircraft/engine combinations using 100% SAF. Already, fuel blends containing up to 50% SAF have been certified by ASTM International, the recognised authority on these matters (ASTM originally stood for the American Society for Testing Materials). Certification of 100% SAF for airliners now seems only a matter of time.

According to IATA, SAF would provide 65% of commercial aviation’s carbon mitigation by 2050. Achieving this goal would require an annual SAF production capacity of 449-billion litres by 2050. Currently, global SAF production capacity is 125-million litres. Investments are already in place to increase this to five-billion litres a year by 2025. But rapid large-scale ramping up of SAF production after that would need incentives, because of the current high cost of these fuels. Last year, the price of SAF varied from two and four times that of conventional jet fuel. However, this year the price of jet fuel has risen dramatically, making SAF more competitive – for the moment.

“Incentives to transition electricity production to renewable sources like solar or wind worked,” highlighted IATA director- general Willie Walsh at the June AGM. “With similar incentives for SAF, we could see 30-billion litres available by 2030. Though still far from where we need to be, it would be a clear tipping point towards our net-zero ambition of ample SAF quantities at affordable prices.”

The US, he pointed out, had taken the lead. That country was providing large incentives that will take its production of SAF to 11-billion litres by 2030.

Southern Africa: Aborted Takeoff

Worldwide, momentum to switch commercial aviation from using fossil fuels to employing SAF is clearly building. In Southern Africa, however, there has thus far been only one SAF test programme. This involved Boeing, State-owned national flag-carrier South African Airways (SAA), global organisation the Roundtable on Sustainable Biomaterials (RSB), Sunchem SA (the South African subsidiary of the Dutch Sunchem company) and Dutch group SkyNRG. The result, in 2016, was the first passenger flight in Africa using SAF, blended with conventional jet fuel, to power a Boeing 737 operated by SAA subsidiary and low-cost carrier Mango. But only once such flight was flown.

SAA’s subsequent financial crisis and later the Covid-19 pandemic have meant that the programme has made no progress for years. However, Boeing and RSB are continuing to work together to support SAF in Southern Africa, by means of a SAF feasibility study. Elsewhere in Africa, Boeing is working in Ethiopia to help that country develop SAF feedstock production capacity and with Ethiopian Airlines to include aviation sustainability in the curriculum of the Ethiopian Aviation Academy.

The lack of SAF activity in Southern Africa is not due to any want of interest on the part of the region’s airlines, or their representative body, the Airlines Association of Southern Africa (AASA). “AASA supports SAF very strongly and is incorporating SAF as a key element of the environmental strategy that will be adopted at its AGM in October,” highlights South African aviation and sustainability consultant, SAF expert and IATA SAF trainer Ian Cruickshank.

Of course, Africa currently contributes only a small amount of total global carbon emissions. But, with the continent’s rapidly increasing population, that proportion will increase. And if the continent lags behind other regions in decarbonising its economy, its relative contribution to greenhouse-gas emissions will grow even more. On the other hand, Africa has enormous potential as a producer of SAF.

That SAF production potential certainly exists in Southern Africa, Cruikshank points out, even if no SAF is currently being produced in the region. The ability to make SAF locally was proven by the Boeing/SAA/RSB/Sunchem/SkyNRG project.

“When the original flights were conducted in 2016, all sustainability issues were covered as we obtained RSB certification for the feedstock,” he assured. “That requires a holistic and comprehensive management system to ensure social, economic and environmental sustainability matters are addressed BEFORE [he stressed] the feedstock can be certified as sustainable. Additionally, we had WWF-SA (World Wide Fund for Nature – South Africa) as partners to scan for unintended consequences and sustainability issues.”

The WWF-SA has been stimulating research into the Southern African production, transport and storage of SAF. Its most recent report on the issue, entitled ‘Fuel for the Future: A Blueprint for the Production of Sustainable Aviation Fuel in South Africa’, released in May, was compiled for it by the Council for Scientific and Industrial Research, Stellenbosch University’s Centre for Process Engineering, Imperial Logistics, and Blue North Consulting, with financial support from Boeing.

“A domestic SAF industry could be a pillar of South Africa’s low-carbon economy, playing a key role in the just transition process,” states the report. The country already has the “technical potential” to make 3.2-billion litres of SAF a year. Adding ‘green hydrogen’ to the SAF production process could increase this to 4.5-billion litres annually. “This is enough to replace the use of conventional jet fuel domestically up to a maximum blending threshold of 1.2-billion litres per annum, while also providing 2[-billion to] 3.3-billion litres for export.”

The country has more than one pathway to develop large-scale domestic SAF production, notes the report. These pathways are largely complementary and so the country does not have to select which to follow, but could simultaneously pursue more than one option, or indeed all the options. Development of a full-scale domestic SAF production system could create more than 100 000 green jobs in South Africa, across the entire supply chain.

“Reducing jet fuel imports by developing a domestic SAF industry can improve South Africa’s balance of trade by R118-billion per annum,” highlights the report. “Full export of all SAF would further improve the balance of trade, generating about R159.5-billion per annum from sales at the minimum sale price.”

The most recent SAF initiative in the region is that of South African chemicals and energy group Sasol. In June, the group signed a memorandum of understanding (MoU) with German aircraft manufacturer Deutsche Aircraft, to develop technologies for green- hydrogen-based ‘power-to-liquids’ (PtL) SAF. Sasol is the world leader in Fischer-Tropsch technology, originally developed in Germany to produce liquid fuels from coal, and the proposed PtL SAF would be chemically similar to Sasol’s coal-to-liquids products. The proposed SAF would probably be produced by using carbon dioxide, taken from the atmosphere, and green hydrogen. The two companies will also work together to achieve the certification of this SAF, both for use in blends and for use on its own.

“Joining forces between aircraft manufacturers and fuel producers is vital, if we want to ensure that aviation becomes sustainable, while ensuring the highest possible safety standards,” noted Sasol ecoFT senior VP Dr Helge Sachs, at the signing of the MoU.

The region’s airport companies are also on-side regarding the adoption of SAF. “They are supportive in general because they do not have to do anything,” observes Cruickshank. “SAF is a drop-in fuel and indistinguishable from conventional jet fuel once blended. An airport wouldn’t notice any changes at all to their processes.”

As a result, a lot of the region’s existing fuel supply infrastructure could be repurposed to produce, transport and store SAF. South Africa’s currently mothballed fuel refineries could, he cites, be re-employed to produce SAF.

Positive Policies Needed

“Acceptance is not a problem and the region is ideally suited for SAF, as we have mapped out the potential feedstocks and considered the sustainability of the feedstock and the outlook is excellent,” he sums up. “We actually have the foundation available to get us moving very rapidly.”

But the region is not moving rapidly. Airlines, airports, petrochemicals companies, researchers, environmental groups are all on-side. “The state of readiness, as distinct from the potential, for the production of SAF is currently an issue, as there are no dedicated projects focusing on the refining of biojet fuels,” he reports.

What is lacking in Southern Africa, and what has happened and is happening elsewhere in the world, is government commitment. “The region’s leadership does not seem to understand the urgency of the emissions reduction challenge nor the incredible macro- and socioeconomic benefits that SAF could bring to the region,” he points out. The responsible government departments are very aware of the issues and opportunities, but seem unable to bring these to the forefront of their respective national policy agendas. On the other hand, governments, such as South Africa’s, have displayed action in imposing carbon taxes, including on the domestic airline industry.

In South Africa, the income from this tax is not ring-fenced for environmental or carbon-emission-reduction programmes and projects (one of which could be the stimulation of local SAF production). So, South African airlines have to pay for their carbon emissions but are effectively prevented from mitigating those emissions. Moreover, international agreements to reduce aviation’s carbon emissions, to which South Africa and other Southern African States are party, will in due time impose financial penalties on airlines that do not reduce their emissions. For Southern African airlines to meet those emission reductions and avoid those penalties will require the local production of SAF.

“It is clear that the region needs some positive policies to get the SAF industry started,” affirmed Cruikshank. “Blending mandates are absolutely useless, as can be seen with current fuel mandates that everyone is simply ignoring.”