Greenhouse gas emissions can be limited through different sustainable solutions without impacting the global energy production. Nowadays the most suitable solution is represented by the insertion of Renewable Energy Sources (RES) and efficient storage systems in the energetic supply chain. In this context, hydrogen represents an interesting way to secure an economic and efficient energy supply in times of energy transition. Several routes can be experienced in the "hydrogen production paths", one of the most interesting is linked to Green Hydrogen since it comes from the coupling between electricity production from RES and electrolysis processes. Dealing with the topics above mentioned PEM water electrolysis is the most promising technique for high-pure efficient hydrogen production exploiting renewable energy sources.