Towards water-conscious green hydrogen and methanol production: A techno-economic review
Wenzel Henrik, Müller Gian, Freia Harzendorf, Schöb Thomas, Felix Kullmann, Jann Michael Weinand, Stolten Detlef
Abstract
<h2>Summary</h2> 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 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 kWh<sub>el</sub>/t<sub>CO2</sub> and 1,257 kWh<sub>th</sub>/t<sub>CO2</sub>, while the capture cost is expected to decrease to 162 €<sub>2024</sub>/t<sub>CO2</sub>, with 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 techno-economic perspective and show a potential reduction in external heat demand of the DAC unit of up to 34% when integrated in the process chain.