The Role of Green and Blue Hydrogen in the Energy Transition—A Technological and Geopolitical Perspective

Hydrogen is currently enjoying a renewed and widespread momentum in many national and international climate strategies. This review paper is focused on analysing the challenges and opportunities that are related to green and blue hydrogen, which are at the basis of different perspectives of a potential hydrogen society. While many governments and private companies are putting significant resources on the development of hydrogen technologies, there still remains a high number of unsolved issues, including technical challenges, economic and geopolitical implications. The hydrogen supply chain includes a large number of steps, resulting in additional energy losses, and while much focus is put on hydrogen generation costs, its transport and storage should not be neglected. A low-carbon hydrogen economy offers promising opportunities not only to fight climate change, but also to enhance energy security and develop local industries in many countries. However, to face the huge challenges of a transition towards a zero-carbon energy system, all available technologies should be allowed to contribute based on measurable indicators, which require a strong international consensus based on transparent standards and targets.