Fig. 4: The effects of hydrogen exports on domestic electricity consumers and domestic CO₂ mitigation on hydrogen exporters.

Panel a shows the effect of hydrogen (H₂) exports on domestic electricity cost with hourly hydrogen regulation. Therefore, the effect of hydrogen exports is isolated by normalizing the costs to 1 TWh hydrogen export in each column. This approach allows for a vertical interpretation in Panel a only, displaying the effects of hydrogen exports (vertical) at a certain domestic CO₂ mitigation level. Panel b shows the effect of domestic CO₂ mitigation on hydrogen export cost with hourly hydrogen regulation. Therefore, the effect of domestic CO₂ mitigation is isolated by normalizing the costs to 0% CO₂ mitigation in each row. This approach allows for a horizontal interpretation in Figure Panel b only, displaying the effects of domestic CO₂ mitigation (horizontal) at a certain hydrogen export quantity. Domestic electricity consumers profit from increasing hydrogen exports, especially at low domestic CO₂ mitigation and high exports. Hydrogen exporters profit from domestic CO₂ mitigation at medium mitigation efforts. See Supplementary Fig. 17 for absolute market-based costs for domestic electricity consumers and hydrogen exporters, Supplementary Fig. 6 for the interplay of hydrogen exports and domestic CO₂ mitigation if no hydrogen regulation is in place and Supplementary Fig. 10 for hydrogen exports up to 200 TWh.