Carbon-neutral methanol synthesis as carbon dioxide utilization at different scales: Economic and environmental perspectives

Methanol is emerging as the carbon dioxide utilization technology and hydrogen carrier that can produce methanol using captured carbon dioxide and hydrogen. In this study, four cases were classified as methanol production according to which pathway was used to produce hydrogen: case 1 (steam methane reforming), case 2 (coal gasification), case 3 (water electrolysis), and case 4 (direct methanol production by carbon dioxide electrolysis). To figure out the best pathway in terms of economic and environmental perspectives, itemized cost estimation, sensitivity analysis, uncertainty analysis, and carbon footprint analysis were performed for four cases of methanol production with methanol production capacities of 1, 10, 20, and 50 ton d-1. From itemized cost estimation reflecting carbon footprint analysis results, respective unit methanol production costs of 3.66, 2.99, 3.69, and 0.55 $ kg- 1 were obtained for methanol production capacity of 50 ton d-1. Compared to the unit methanol production cost (0.396 $ kg- 1) from fossil fuel-based production, direct methanol production has become feasible than other cases. And, from sensitivity and uncertainty analysis, the cost of reactant and electricity were major economic parameters for cases 1-3 and case 4, respectively, and the possible unit methanol production cost ranges due to the cost fluctuations in future were investigated.