(680f) Impact of Process Flexibility on the Techno-Economics of e-Kerosene Production Via the Methanol and Syngas Routes

The global push to achieve net-zero carbon emissions by 2050 has intensified the need for sustainable fuel alternatives, particularly in the aviation industry, which accounts for 2.5% of the global carbon dioxide emissions [1]. As of 2024, only biomass-based technologies have been commercialized for sustainable aviation fuel (SAF) production, meeting only 0.53% of the total jet fuel demand [2]. Biomass-derived fuels only reduce carbon emissions by 50-80% and will ultimately not be sufficient to meet the global demand for SAF [3]. Power-to-liquid (PtL) technologies [4] are the most commonly discussed alternative, which uses captured carbon dioxide and hydrogen produced using renewable electricity to manufacture e-kerosene [5]. One major challenge with PtL technologies is associated with the intermittency of renewable energy sources such as wind and solar, which can have a significant impact on the plant’s operability and economic performance.

In this work, we consider two chemical pathways for producing e-kerosene, one via methanol and the other via syngas as an intermediate. While the syngas route uses established technologies such as the Fischer-Tropsch process [6], methanol production via carbon dioxide hydrogenation is a less mature technology. However, methanol is much cheaper to store than syngas, which may offer a key advantage under intermittent input of renewable energy. To compare the two routes under such conditions, it is important to understand the role of operational flexibility and its impact on the economics of the process.

Using a combined design and scheduling optimization model [7] for each of the two routes, we investigate how the optimal equipment sizes, production schedule and the resulting levelised cost of e-kerosene (LCOK) change as functions of the process’s operating range (OP) and ramping limits. We consider a case study with an e-kerosene demand of 5000 kg/hr; it requires about 185,000 mt/yr of carbon dioxide which is the amount that is released from a typical bioethanol plant [8]. The results indicate that over 60% of the total cost is attributed to renewable electricity generation, using wind turbines and solar PV, and electrolysers. Our analysis shows that changing the minimum allowed production level of the methanol synthesis process from 90% (OP: 10%) of its capacity to 50% (OP: 50%) reduces the LCOK from $5.37/kg to $4.80/kg, primarily due to the lower cost of storing methanol as compared to hydrogen. Beyond 50%, additional increase in the operating range only yields negligible cost savings. In contrast, there is virtually no change in the LCOK of $5.44/kg with the operating range of the reverse water gas shift reaction process in the syngas route, primarily because the cost of storing syngas is higher than the cost of storing the equivalent amount of hydrogen. This study projects an approximately 50% reduction in the LCOK by 2050 for both the methanol and syngas routes, mainly driven by decreasing low-carbon technology costs. The study also shows that economies of scale (EOS) have limited impact under the 2025 conditions but become more significant by 2050 for both routes. This shift occurs because the share of the LCOK contributed by the renewable technologies, which do not benefit from EOS, decreases, while the share associated with chemical processes benefiting from EOS increases between 2025 and 2050.

References

[1] Our World in Data. Global aviation emissions. Accessed: 2024-12-20. 2024. URL: https : / / ourworldindata.org/global-aviation-emissions.

[2] OPIS (Oil Price Information Service). Jet Fuel Demand Continues to Recover. Accessed: 2024-12- 21. 2024. URL: https://www.opisnet.com/blog/jet-fuel-demand-continues-to-recover/.

[3] Tonni Agustiono Kurniawan. “Uncovering the Potential of Biomass from Agricultural Waste as Sustainable Biofuel in Aviation Industry to Promote Net Zero Emissions: A Critical Review”. In: BioResources 20.2 (2025).

[4] Eric G. O’Rear, Whitney Jones, Galen Bower, Emily Wimberger, and John Larsen. Sustainable Aviation Fuels: The Key to Decarbonizing Aviation. Accessed: 2025-03-12. 2022. URL: https:// rhg.com/research/sustainable-aviation-fuels/.

[5] Konstantinos Atsonios, Jun Li, and Vassilis J Inglezakis. “Process analysis and comparative assessment of advanced thermochemical pathways for e-kerosene production”. In: Energy 278 (2023), p. 127868.

[6] Stefan Bube, Nils Bullerdiek, Steffen Voß, and Martin Kaltschmitt. “Kerosene production from power-based syngas–A technical comparison of the Fischer-Tropsch and methanol pathway”. In: Fuel 366 (2024), p. 131269.

[7] Qi Zhang, Mariano Mart´ın, and Ignacio E Grossmann. “Integrated design and operation of renewables-based fuels and power production networks”. In: Computers & Chemical Engineering 122 (2019), pp. 80–92.

[8] U.S. Energy Information Administration. Ethanol Plant Production Capacity. Accessed: 2025- 01-22. 2025. URL: https://www.eia.gov/petroleum/ethanolcapacity/.