Decarbonisation Technology - February 2025 Issue

ENVIRONMENTAL IMPACT

SOURCES

PROCESS

FUEL TYPE

Petroleum fuel

Lower than petroleum diesel 70%

Biofuel

Lower than petroleum diesel Up to 90%

Figure 1 Progression of biofuels development has resulted in up to 90% lower emissions than from petroleum diesel

than 130 renewable fuel projects announced by more than 85 producers across 30 countries globally ( Thomsen, Mistry, & Block, 2023 ). Government incentives are playing a crucial role in driving SAF adoption. In the US, the Sustainable Aviation Challenge sets an ambitious goal for the airline industry to use 11 billion litres of SAF by 2030, equivalent to 15% of current jet fuel demand ( US DOE, 2021 ), ( IATA, 2022 ). The EU’s Fit for 55 package includes a proposed 2% SAF blending mandate by 2025 under the ReFuelEU Aviation initiative ( European Commission, 2022 ). One of the key advantages of SAF is its drop- in capability, meaning it can be used in existing aircraft engines without modification. This characteristic makes it an attractive option for airlines looking to reduce their carbon footprint without investing in new aircraft or engine technologies. Renewable diesel While SAF is focused on decarbonising aviation fuels, renewable diesel is transforming the road transportation sector, particularly for heavy-duty vehicles and long-haul trucking. Renewable diesel should not be confused with biodiesel, an earlier biofuel that gained popularity in the past decade.

Renewable diesel offers several advantages over biodiesel. It burns more cleanly and efficiently, produces lower emissions, and can be used in high concentrations without blending with traditional diesel (see Figure 1 ). These characteristics make it an attractive option for fleet operators looking to reduce their environmental impact without significant changes to their existing vehicles. The International Energy Agency (IEA) projects that renewable diesel production will triple by 2026 ( IEA, 2022 ). This growth is driven by increasing demand from road and sea haulage sectors, which have limited options for transitioning away from traditional combustion engines in the short term. Feedstock challenges and innovations The choice of feedstock is crucial in the production of both SAF and renewable diesel. Early biofuel production relied heavily on vegetable oils, resulting in fatty acid methyl esters (FAME) or biodiesel. However, concerns about fuel blending and engine compatibility have shifted focus to hydrotreated processes for drop-in fuels. Hydrotreated vegetable oils (HVO) have emerged as a popular option for producing