The green hydrogen revolution

Green hydrogen is considered the most suitable choice for the future energy market, both as energy storage media, energy vector and fuel for transportation, industry and other applications.In the last twenty years, increasing efforts have been dedicated to green hydrogen technologies development, but still today a number of issues are claimed in justifying the delay in its large scale application and the starvation of its market. Moreover, some new questions seem ready to be put on the table for justifying the delay in green hydrogen technologies applications.In this paper, a critical analysis of recent literature and institutional reports is carried out with the aim of understanding what is the real state of the play. In particular, peculiar advantages and shortcomings of different green hydrogen technologies (biomass pyrolysis and gasification, water electrolysis, etc.) have been analysed and compared, with a focus on the electrolysis process as the most promising method for large scale and distributed generation of hydrogen.Some geopolitical and economic aspects associated with the transition to a green hydrogen economy-including the feared exacerbation of the water crisis -have been widely examined and discussed, with the purpose of identifying approaches and solutions to accelerate the mentioned transition.