Techno-economic analysis and optimization of an alkaline water electrolysis in Power-to-Methanol process

Abstract

The transition to a sustainable energy system urgently calls for effective and economically viable power-to-X technologies. The Power-to-Methanol (PtM) concept is among the most promising uses of renewable electricity for producing synthetic fuels and chemicals on the pathway to carbon neutrality. A critical element of PtM involves the production of hydrogen by Alkaline Water Electrolysis (AEL), complemented by the capture of carbon dioxide from the atmosphere through Direct Air Capture (DAC). The hydrogen and CO2 are then synthesized using direct hydrogenation of CO2 into methanol - a versatile fuel and chemical feedstock. This thesis performs a detailed techno-economic analysis and optimization of an integrated PtM process, with high-pressure AEL and DAC as core components. A detailed process simulation is developed to evaluate the effect of pressure of AEL as well as entire system efficiency, AEL power consumption, and the interactions between various process variables. Sensitivity analysis pinpoints significant operating variables affecting performance and economic viability of the process: efficiency of electrolyzers, energy consumption by DAC, and methanol yield. Further optimization of various strategies for an advanced integration approach will be done, consuming less energy and consequently decreasing the cost of hydrogen production. On the other hand, a detailed economic analysis is performed regarding capital investment, operational expenses, net production cost of methanol, and other possible streams of revenue using DLR in-house tools. It also considers the impact of fluctuating electricity prices and policy incentives on overall economic feasibility. The results obtained in this research will provide broad insights into the viability and competitiveness of PtM ystems using pressurized AEL and DAC. This research addresses technical and economic challenges; hence, it contributes to the development of sustainable pathways of the fuel production, hence supporting the transition toward low-carbon energy.