Navigating Turbulence: Hydrogen’s Role in the Decarbonization of the Aviation Sector
Despite consistent efficiency gains in aviation, the sector’s rapid growth has led to a substantial increase in emissions, accounting for 2% of global energy-related CO2 emissions in 2022—roughly 80% of pre-Covid-19 pandemic levels.
In today’s aviation landscape, the sector relies on conventional aviation fuels. To achieve meaningful decarbonization in aviation, the fundamental source of emissions—the fuel—must be addressed.
Two key methods come to the forefront for addressing the challenge of decarbonizing aviation. Firstly, decarbonizing the fuel itself offers a solution without requiring structural change in how aircraft operate and fly today. Secondly, innovation in the means of propulsion could pave the way for aviation to shift from carbon-based fuels to hydrogen combustion or even entirely non-combustion methods like electricity.
Battery electric propulsion provides higher system efficiencies. Yet, it also poses a multitude of issues for commercial aviation. The primary challenge lies in their relatively low specific energy. In the foreseeable future, this type of propulsion will likely be suitable for light-payload and limited-range aircraft.
Hydrogen-based propulsion can be utilized in aircraft through two distinct methods: firstly, via hydrogen combustion, and secondly, through the use of fuel cells. However, widespread adoption of these aircraft and the development of their necessary infrastructure will inevitably take time. Hydrogen-powered flight is unlikely to serve as the primary means to achieving carbon neutrality by the mid-21st century. This accomplishment is more likely to be attributed to Sustainable Aviation Fuels (SAFs) and further efficiency enhancements.
Given that 80+ per cent of life cycle emissions are released at the combustion phase of the aviation fuel. Lower Carbon Aviation Fuels (LCAFs) encompass a diverse array of innovative technologies and processes aimed at curbing GHG emissions in the production phase of aviation fuel, which translates to GHG emissions reductions comparable in effect to efficiency gains that were only seen in the 1970s when the Boeing 747 was introduced with its HBR turbofan engines.
Numerous stakeholders in the aviation sector share the belief that SAF will be the primary driver behind significant reductions in fossil-based emissions by the 2050-2060 waymark.
SAF can be generated through various pathways, with hydrogen expected to play a significant role in eSAF production. Nevertheless, hydrogen is vital in the processing and refining of most SAF pathways, and the expansion of the SAF value chain is anticipated to be intricately connected to the development of decarbonized and renewable hydrogen.