Towards Water-conscious Green Hydrogen and Methanol: A Techno-economic Review

To enable a sustainable and socially accepted hydrogen and methanol economy, it is crucial to prioritize green and water-conscious production. In this review, we reveal that there is a significant research gap regarding comprehensive assessments of such production methods. We present an innovative process chain, consisting of adsorption-based direct air capture, solid oxide electrolysis and methanol synthesis to address this issue. To allow future comprehensive techno-economic assessments, we perform a systematic literature review and harmonization of the techno-economic parameters of the process chain’s technologies. Based on the conducted literature review we find that the long-term median specific energy demand of adsorption-based direct air capture is expected to decrease to 204 kWhel/tCO2 and 1257 kWhth/tCO2 while the capture cost is expected to decrease to 162 €2024/tCO2 with a relative high uncertainty. The evaluated sources expect a future increase in system efficiency of solid oxide electrolysis to 80% while the purchase equipment costs are expected to decrease significantly. Finally, we demonstrate the feasibility of the process chain from a technoeconomic perspective and show a potential reduction in external heat demand of the DAC unit of up to 34% when integrated in the process chain.