The Potential of CO 2 Hydrogenation to Produce e-Fuels: Thermodynamic and Techno-economic Analysis

Since the 19th century, petroleum has underpinned societal development and industrial progress, serving as a primary source of heating, power, and transportation fuels. However, its detrimental effects on the environment and urban areas have highlighted the urgent need to transition toward more sustainable energy alternatives. CO2 hydrogenation to electrofuels (i.e., e-fuels) emerges as a promising pathway for cleaner energy production. This study focuses on the thermodynamic and techno-economic aspects for 12 different e-fuels: methane, ethane, propane, butane, pentane, gasoline, kerosene, diesel, methanol, ethanol, butanol, and dimethyl ether. For thermodynamic assessment, Aspen Plus V14 software was used to simulate an equilibrium reactor fed with pure CO2 and H2 streams under different temperatures, pressures, and H2/CO2 ratios. The results showed an increase in fuel fractional yield and CO2 conversion with higher pressure and lower temperatures. The initial economic analysis considered the determination of the production phase rentability parameter (i.e., α); a value above 1 indicates that fuel sales surpass the combined costs of green hydrogen and operational expenditure. Excluding capital expenditure and assuming fuel prices equivalent to conventional production methods, the analysis revealed potential rentability for gasoline under both best- (200 °C, 50 bar) and worst-case (350 °C, 20 bar) conditions, corresponding to the highest and lowest yields, respectively, whereas diesel was found to be profitable only under the best-case scenario. When capital expenditure and parameters such as workforce were considered, the initial investment was estimated at approximately 7–8 million euros, excluding additional costs associated with gas purification, transport, and storage. The cumulative cash flow showed progressive decreases, suggesting the unviability of the project under current conditions. However, a sensitivity analysis of hydrogen costs indicated potential feasibility for gasoline and diesel production if hydrogen prices drop to half their current levels.