The Fuel Cell and Hydrogen 2 Joint Undertaking and its successor Clean Hydrogen Joint Undertaking set a series of key performance indicators (KPIs) that allows tracing the progress toward hydrogen production from renewable electricity coupled with water electrolysis. They are related to Energy consumption (KPI 1); Capital Expenditure (KPI 2); Efficiency Degradation (KPI 3); Flexibility (KPI 4); and Hot/Cold start (KPI 5). These 2023 KPIs are general technical goals settled to be fulfilled by all water electrolysis technologies. In that sense, the Clean Hydrogen JU settled for 2024, 2030, and beyond KPIs accordingly to each water electrolysis technology. Even though the KPIs are now adapted to each technology, the conditions assumed for each KPI are far to be a standard procedure on how it should be measured making it very difficult to do a direct comparison among technologies and between manufacturers. Despite that, these settings might be difficult to be reached with some of the available technologies due to their current inherent characteristics and especially for those less mature technologies. Nowadays, there is no specific electrolyser technology outperforming the rest across all the features essential for the effective production of renewable hydrogen. Nevertheless, currently, due to their maturity and despite their limitations, both AWE and PEMWE technologies will draw the main attention, although further R&D of AEMWE, SOEL, and PCCEL would bring those less mature technologies as alternative solutions in the future. In the end, innovation, and competition among these key technologies and their manufacturers, will lead to technological improvements and a better fit for different technologies and system designs on a case-by-case basis.