Fig. 4: Comparison of domestic synthetic production costs and import costs for varying import scenarios.

The three panels (a–c) refer to different import scenarios. In each panel, the bar charts show the production-weighted average costs of domestic production of steel, hydrogen and its derivatives, split into its cost and revenue components. These have been computed using the marginal prices of the respective inputs and outputs for the production volume of each region and snapshot. Capital expenditures are distributed to hours in proportion to the production volume. Missing bars indicate that no domestic production occurred in the scenario, e.g., for the case of methane, where all demand is met by biogenic and fossil methane and no synthetic production occurred (cf. energy balances in Supplementary Figs. 24–25). All hydrogen is produced from electrolysis; i.e., the model did not choose to produce hydrogen via steam methane reforming with or without carbon capture. For each bar, the yellow error bars show the range of time-averaged domestic production costs across all regions. The black error bars show the range of import costs across all regions. The maps on the right of each panel relate the hydrogen production volume to the weighted cost of domestic hydrogen production (colorbar). The shown scenarios use technology assumptions for 2040, allow crude steel and ammonia relocation, and do not constraint import volume in (b, c). Confer Supplementary Fig. 22 for information on the domestic cost supply curves. Source data are provided as a Source Data file. Maps made with Natural Earth. HBI = hot briquetted iron.