Hydrogen is gaining importance in the transformation of the energy industry due to its multiple uses as an energy vector. Currently, the main production has a fossil fuel origin through processes such as coal gasification or natural gas reforming . The related Levelized Cost Of Hydrogen (LCOH) oscillates between 1.3 and 2.5 €/kg, depending on the technology and location . In the next future, hydrogen produced from renewable energy could become competitive not only due to the progressive reduction in the technologies costs , but also due to CO2 taxes in certain regions . Recently, LCOH of 2,8-3,5 €/kg for hydrogen production from off-grid PV plant have been reported in Australia , thus showing that hydrogen production from solar plants could already be competitive in certain locations. Currently, two commercially available electrolysers technology exist: alkaline electrolysers and proton exchange membrane (PEM) electrolysers. Alkaline electrolyser are a fully mature technology commonly used for large-scale systems due to their longer lifetime and cheaper cost . However, they have several drawback such as a slower response time in case of dynamic operations . On the other hand, PEM electrolysers have larger flexibility in terms of power fluctuations, but present larger costs . In this work, alkaline electrolyser have been preferred due to their smaller costs for large scale production. Solar PV plants have an inherent variability in the power production caused by the fluctuation of the solar resource. Previous works have demonstrated the difference in variability when considering a single point irradiance measurement compared to large PV plants power production measurement because of the smoothing within the plant due to the spatial extent of PV modules . However, when calculating the LCOH of utility scale PV plants coupled with hydrogen electrolysers, historical data is often unavailable.