Figure shows the development distance distribution of all models with a LCOH2 in the target cost range. From this analysis, we can obtain the mean development distances that are required to achieve cost-competitiveness. As already indicated by Figure , PEC displays the longest mean development distance (0.86, standard deviation: 0.043) and only a very small number of models actually reach the target cost range (low frequency values on the y axis). The high mean development distance means that almost all potential for technological improvement has to be exhausted in order to produce hydrogen at the defined target cost. PC shows a significantly shorter mean development distance of 0.72 with a relatively broad distribution of models from 0.5 to 0.85 (standard deviation: 0.076). This implies that, while a significant amount of progress is required, the target cost can be achieved without having to use all of the innovation potential. In case of PV+E, the shortest mean development distance of 0.61 is observed with an equally broad distribution compared to PC (standard deviation: 0.080). Within the assumptions of this study, the shortest mean development distance indicates that PV+E requires the least amount of technological progress to reach costcompetitiveness.