This master thesis is structured into multiple chapters. Initially, the Literature Review will focus on why it is important to study innovation and innovative activities, which are at the basis for the development of economic development, growth and prosperity; secondly it will explain, through the analysis of previous studies how and why it is appropriate to study innovation through the output, and more specifically using patents, considering both advantages and disadvantages of using this method; last it will report studies that have been conducted, especially in recent years on green patented technologies and more specifically hydrogen technologies, illustrating their findings. Following the review of past literature, a chapter will be dedicated to the representation of the hydrogen value chain: from the production to the storage, distribution, transformation, and end- uses of this extremely versatile and promising resource.