Assessing the operational environment of a P2X plant from a climate point of view

Abstract

Production of synthetic fuels is important for a faster reduction of transport emissions. Power-to-gasoline technology can utilize CO2 captured from industrial processes as well as hydrogen to produce synthetic gasoline as a substitute fossil-derived fuel. However, greenhouse gas emission reductions, in this case, cannot be taken for granted. This study analyzes changes in greenhouse gas emissions caused by the integration of a power-to-gasoline plant into an existing operational environment in Lappeenranta, Finland. The operational environment consists of a cement plant, which is the CO2 source, a chlor-alkali plant producing excess hydrogen, and a gasoline plant. Cradle-to-gate greenhouse gas emissions of a system with a power-to-gasoline plant were compared to a baseline system with a conventional oil refinery using life cycle assessment methodology. Two cases of power-to-gasoline plants, one utilizing excess hydrogen and another with an electrolyzer, and four scenarios with different energy sources were compared to analyze the influence of hydrogen and energy sources on the system's greenhouse gas emissions. The results show that depending on energy sources, the use of excess hydrogen leads to a 22–40 kt CO2-eq (44%–77%) emission reduction compared to the baseline (51.5 kt CO2-eq). In the case of hydrogen production by water electrolysis, the use of renewable electricity for the electrolyzer leads to a 27 kt CO2-eq (53%) emission reduction compared to the baseline. The use of renewable heat increases the emissions reduction in this case to 37 kt CO2-eq (72%). In such scenarios, hydrogen production from water electrolysis can be more beneficial for the emissions reduction compared to the excess hydrogen utilization if the by-product oxygen from electrolysis substitutes oxygen obtained from air separation and the need for CO2 transportation is eliminated by building the plant close to the CO2 source.