Unlocking Sustainable Aviation: Leveraging CCUS for Net-Zero Emissions

The International Air Transport Association (IATA) has set its sights on achieving “net zero carbon emissions” by 2050. In 2019 alone, global flights contributed a staggering 915 million tonnes of CO2 to the atmosphere, adding to the already substantial burden of over 43 billion tonnes of CO2 produced annually by human activities. Without significant intervention, projections suggest that by 2050, aviation-related emissions could soar to 1.8 billion tons. This industry currently accounts for approximately 2.1% of all human-induced carbon dioxide emissions, with the number of passengers carried by airlines increasing steadily each year.

Jet fuel, the primary fuel used in gas-turbine-powered aircraft, typically consists of carbon chains ranging from C8 to C18, with the optimal chain length falling between C8 and C16. Given the industry’s reliance on fossil fuels, there’s a pressing need to explore alternative pathways to mitigate greenhouse gas emissions and achieve net zero emissions targets. Converting CO2 into fuels has emerged as a promising solution, garnering significant attention globally over the past decade. This approach not only reduces emissions but also produces valuable chemical commodities, offering a pathway toward sustainability.

Renewable and synthetic fuels have been identified as essential components in global efforts to combat climate change. Organizations such as the International Energy Agency (IEA), the Intergovernmental Panel on Climate Change (IPCC), and the World Economic Forum advocate for the widespread adoption of these fuels to align with global climate ambitions.

Liquid fuels derived from petroleum crude fractionation boast high gravimetric energy density, making them indispensable in the transportation sector, where they currently satisfy 60% of global oil demand. For instance, a liter of gasoline weighing approximately 0.75 kg stores an impressive 35 MJ of energy. In comparison, providing an equivalent amount of energy with a 50 kg lithium-ion battery would be required. While electric motors are more efficient than internal combustion engines, regenerative braking falls short in compensating for the added weight of batteries. Synthetic fuels offer a viable solution by providing an indirect pathway from low-carbon electricity to energy-dense fuel applications.

There are two primary methods for converting CO2 into liquid fuels: indirect and direct routes. In the indirect route, CO2 is first converted to CO or methanol before being transformed into liquid hydrocarbons. Conversely, the direct route involves the reduction of CO2 to CO through the reverse water-gas shift (RWGS) reaction, followed by the hydrogenation of CO to long-chain hydrocarbons via Fischer-Tropsch synthesis.

Fischer-Tropsch (FT) synthesis stands out as a widely utilized method for producing synthetic fuel. This technology, named after its inventors Franz Fischer and Hans Tropsch, yields a range of products suitable for various applications. These products include light gases (C1-C4), naphtha (C5-C11), diesel (C9-C20), and waxes (C20+), with the choice of catalyst and operating conditions influencing the product distribution. The Norsk e-Fuel project is pioneering the commercial application of FT synthesis in Europe, with its first plant expected to commence operations in 2023, boasting a production capacity of 10 million liters per year.

In conclusion, leveraging CCUS technologies for the production of synthetic aviation fuels offers a promising pathway to achieving net-zero emissions in the aviation industry. By investing in innovative solutions and embracing sustainable practices, the aviation sector can pave the way for a greener and more sustainable future.