Decarbonisation Technology - February 2024 Issue

Decarbonising the aviation industry The future of sustainable aviation fuels is driven by a commitment to ambitious decarbonisation targets and continuous innovation

Yvon Bernard, Carine Leclercq and Nicolas Simon Axens

T o address the array of climate targets set by national and international authorities worldwide, industries in every sector must seek efficient and dependable solutions in the transition from fossil fuels. These heightened demands, driven by environmental concerns and sustainability regulations, have created the complex challenge of finding cost-effective solutions to reduce reliance on fossil fuel resources. Achieving these ambitious targets – as outlined by the Intergovernmental Panel on Climate Change and various national pathways toward achieving net-zero emissions – will require behavioural changes, efficiency gains, and the leverage of renewable or low-carbon energy sources available around the world, including solar energy, wind energy, biomass, and more. Rising sustainability standards in the aviation industry Sustainable aviation fuel (SAF) is one of the solutions to decarbonise the aviation industry. Just as SAF must be combined with other decarbonisation solutions, experts do not expect that one single SAF production technology will be able to meet the increasing demand for this fuel. For this reason, government agencies, refining companies, and aviation industry stakeholders are collectively investigating the full range of technology pathways to substitute fossil-based jet fuel with SAF based on renewable sources. These sources include agricultural and forestry residues, alcohols, wastes, and energy crops, as well as CO₂ and renewable hydrogen. Today, aviation accounts for 3% of global greenhouse gas emissions, including 890

megatons of CO₂ emitted in 2022. For this reason, the International Civil Aviation Organization has set ambitious goals to reduce net CO₂ emissions by half by 2050, in comparison to 2005 levels. Furthermore, the global air transport industry, through the Air Transport Action Group, has embraced a long- term climate goal of net-zero emissions by 2050. This confirms the commitment of global airlines, airports, air traffic management, and manufacturers of aircraft and jet engines to reduce their CO₂ emissions in line with the Paris Agreement’s goal of limiting global warming to 1.5°C by 2100 (UNFCC, 2015). Main regulatory frameworks for SAF SAF will be essential to achieving the aviation industry’s ambitious decarbonisation targets. Regulations will play a large part in increasing the share of SAF used in aviation and defining the products that will qualify as SAF. Currently, there is no global consensus on these regulations. However, two main approaches currently exist in the industry. In the US, many fuel purchasers are considering carbon-intensity-based metrics to evaluate fuel sustainability, commonly utilising tools such as the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model developed by Argonne National Laboratory. Such models do not group feedstocks or processes by category, but rather they scientifically calculate a given feedstock’s overall greenhouse gas emission profile considering its production, transportation, processing, and use. The outcome is a scientifically based and quantified