Green hydrogen (GH₂) is emerging as a key driver of global energy transition, offering a sustainable pathway to decarbonize energy systems and achieve climate objectives. This review critically examines the state of GH₂ research production technologies and their integration into renewable energy systems, supported by a bibliometric analysis of the recent literature. Produced via electrolysis powered by renewable energy, GH₂ shows significant potential to decarbonize industries, enhance grid stability, and support the Power-to-X paradigm, which interlinks electricity, heating, transportation, and industrial applications. However, widespread adoption faces challenges, including high production costs, infrastructure constraints, and the need for robust regulatory frameworks. Addressing these barriers requires advancements in electrolyzer efficiency, scalable fuel cell technologies, and efficient storage solutions. Sector-coupled smart grids incorporating hydrogen demonstrate the potential to integrate GH₂ into energy systems, enhancing renewable energy utilization and ensuring system reliability. Economic analyses predict that GH₂ can achieve cost parity with fossil fuels by 2030 and will play a foundational role in low-carbon energy systems by 2050. Its ability to convert surplus renewable electricity into clean energy carriers positions it as a cornerstone for decarbonizing energy-intensive sectors, such as industry, transportation, and heating. This review underscores the transformative potential of GH₂ in creating a sustainable energy future. By addressing technical, economic, and policy challenges and through coordinated efforts in innovation and infrastructure development, GH₂ can accelerate the transition to carbon-neutral energy systems and contribute to achieving global climate goals.