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Examining the role of SAF in a net-zero aviation industry

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The aviation industry is responsible for 2-3% of global CO2 emissions.

With current projections estimating an increase in air travel from two to five billion passengers by 2050, CO2 emissions could reach 21.2 gigatons a year.

These need to be abated if the aviation industry wants to reach its net-zero targets.

Sustainable aviation fuel (SAF) has the potential to cut lifecycle emissions from aviation by up to 80%, making it the largest contributing factor to decarbonising air travel.

Biofuels International asks Angela Robledo, Business Development Director, Low-Carbon Fuels at Worley about the firm’s contributions to this market and the role of SAF in the aviation industry.

What is Worley’s biggest impact in the SAF industry?
Worley’s purpose of delivering a more sustainable world has our people, customers, and planet in mind. SAF is one of the sustainable, lowcarbon solutions that will contribute to a cleaner future.

By partnering with our customers, we’re delivering projects to help them to achieve their net-zero targets and that supports a society that has an everincreasing appetite for low-carbon solutions. We transform ideas and concepts into reality.

With a portfolio of over 80 low-carbon fuels projects, we design and engineer these types of plants around the world.
For instance, we’ve been working for the past two years with Shell to design and build its biofuels facility at Shell’s Energy and Chemicals Park in Rotterdam. Once operating, it will be one of the largest of its kind in Europe, producing 820,000 tonnes of SAF and renewable diesel every year.

How much investment is required to decarbonise the aviation industry?
The International Air Transport Association (IATA) has estimated the cost to decarbonise the aviation industry at US$1.55 trillion (€1.42 trillion) over the next three decades. During COP26, over $130 trillion (€123 trillion) of private capital was committed to transforming the world’s economy to achieve netzero, which means funding availability is not the roadblock to achieving decarbonisation. However, these funds are very carefully allocated to projects, where technical and commercial risks must be mitigated.

The capital deployment required to develop infrastructure, scaleup production and support the commercialisation of new technologies and concepts is critical. We can only move forward and reduce risks if the industry works together to achieve the common goal.

What technology pathways have been developed to produce SAF?
There are seven technology pathways approved by the American Society for Testing and Materials (ASTM) to produce SAF.

These can be grouped into five main categories: hydroprocessed esters and fatty acids (HEFA), alcoholto- jet (ATJ), Fischer-Tropsch (FT), hydrothermolysis and microbial conversion. HEFA is the only one demonstrated at large industrial commercial scales with a projected capacity of approximately 90,000 barrels per day by 2025.

ATJ and FT synthesis are catching up quickly, with some projects in Europe and the USA expected to come on stream later this year.

Hydrothermolysis and microbial conversion are proven at small demonstration or pilot facilities, with additional research and development needed to achieve their full potential. Our expertise in process technologies and delivery models allows us to deliver projects for our customers regardless of the technology they select to reach their low-carbon fuels targets.

There are concerns that SAF is sourced from biomass that competes with the food supply chain. How are SAF producers tackling this challenge?
Today, most SAF is produced from fats, oils and greases (FOGs) using the HEFA pathway.

The availability of feedstocks, synergies with existing infrastructure and ease of retrofitting existing hydroprocessing units are all contributing factors for this technology to take a leading position in the market.

While SAF produced via this route is demonstrating that cleaner aviation fuel is possible, some of the feedstocks being used such as soybean oil, compete directly with food supply. Oil crop production uses agricultural land and water resources that can be used to grow edible crops instead.

These factors are driving the price of these vegetable oils, which has a twofold effect in this supply chain. The availability of these oils for food consumption is declining and the cost of producing of SAF is increasing.

Estimates show that FOGs alone will not be available or cost competitive to supply the entire SAF demand estimated from 2030.

By then, we will need to make use of alternative feedstocks, such as municipal solid waste (MSW) and waste carbon for synthetic SAF production. Logistics and the quality of MSW and technologies to effectively capture and clean carbon are challenges that we’re working on with our customers. As we solve them, synthetic SAF, or e-jet, will increase its contribution to the supply of clean jet fuel that aircraft will be powered by.

SAF is a cleaner alternative, but is it cost competitive?
Today, the cost of production of SAF is significantly higher than fossil-derived jet fuel. The HEFA pathway provides the lowest production cost but it is still around two times higher than fossil jet fuel. Using gasification plus FT or ATJ, costs can be up to six times higher.

This is because of the high capital costs of some of the elements in the process. However, we’re seeing a decline in capital costs over time as demonstration plants come online and developers and financiers back larger plants.

Economies of scale are critical to achieving a lower cost per litre of SAF produced. At the same time, we need incentives and tax credits to lift smaller plants using novel concepts off the ground. The US government has recently announced up to US$4.3 billion (€4.07 billion) to support SAF projects and fuel producers with an aim to boost domestic supply to at least three billion gallons of SAF per year by 2030.

In Europe, governments are granting funds to finance early project development work and some European countries have already implemented an SAF mandate. These mandates and incentives drive the demand of SAF and gives certainty to owners that they will reach long-term offtake agreements with airlines.

What goals need to be achieved in this decade?
A net-zero target for 2050 is aviation’s goal but it might look too far away and consequently, we might not feel a sense of urgency today. However, with thousands of tonnes of CO2 to abate every year, every second counts.

Governments, producers and other industry players have set milestones along this long journey, with 2025 and 2030 being the first key checkpoints. According to announced renewable fuels projects, SAF production capacity is likely to reach over seven billion litres by 2025, increasing to 20-25 billion litres by 2030.

This is in line with IATA’s decarbonisation pathway, which requires 23 billion of SAF by 2030, equivalent to 5.2% of the total jet fuel demand. At Worley, we recognise that these goals will only be achieved through integrated and agile project teams applying fast but rigorous execution approaches that can match the level of capital deployment that is required.

What are the biggest engineering challenges Worley is finding solutions for?
There are several challenges that we’re finding engineering solutions for.

For instance, the quality of the biomass waste or municipal solid waste that feeds the process units is critical. This varies daily and managing the pretreatment and impurity decontamination is of vital importance to protect downstream catalysts and ensure final product quality.

Another challenge that we consider very early on in a project design is the integration of the multiple process units and licensors that conform to the facility. We see innovative opportunities around recycle streams between the gasifier and the partial oxidiser in a FT scheme or around the recycled wastewater streams produced as a by-product.

This creates a significant level of coordination and design iterations between technology licensors and operational risks that we must mitigate. It also adds complexity when defining the operating envelope as the recycles depend on a number of factors, such as catalyst, technology, by-products handling strategy and final product going to market.

Also worth mentioning is the uniqueness and firstof- a-kind technologies or elements that a SAF flow scheme often contains. The integration of these with existing established technologies and infrastructure is essential for the successful operation of the plant.

Will the aviation industry achieve its net-zero commitments by 2050?
We think it’s possible for the aviation industry to reach its net-zero targets. In addition to replacing fossil-derived jet fuel, the industry will implement other emissions abatement initiatives such as energy efficiency improvement solutions, carbon capture and storage facilities and will join carbon offsets schemes.

Also, world-leading manufacturers are designing hydrogen-fuel and electric aircraft, planned to be in the air by mid-2030s. The production of SAF will still be the key element to achieving a net-zero aviation industry by 2050. We’re witnessing increasing support from governments and regulators that will drive SAF demand.

The industry is coming onboard to decarbonise operations and accelerate the production and supply of SAF. We’re working to achieve a cleaner aviation industry – we have the tools and solutions to achieve net-zero. Let’s make it happen.

For more information: Visit: worley.com or contact Angela Robledo at angela.robledo@worley.com

Reference: 1. iea.org/reports/tracking-aviation-2020 2. iata.org/en/programs/ environment/flynetzero/ 3. whitehouse.gov/briefing-room/ statements-releases/2022/04/12/ fact-sheet-using-homegrownbiofuels- to-address-putins-pricehike- at-the-pump-and-lowercosts- for-american-families/