Green hydrogen, derived from water electrolysis using renewable energy sources, is emerging as a critical component in the energy transition towards decarbonisation. Unlike hydrogen produced from fossil fuels, green hydrogen is considered a clean and sustainable alternative as it results in zero direct emissions, making it valuable for sectors like long-haul transportation and power storage. The process of electrolysis, splitting water into hydrogen and oxygen using electricity, is the foundation of green hydrogen production. The efficiency and cost-effectiveness of this process depend on the type of electrolyser technology used, with advancements focused on enhancing performance and scalability while reducing costs. Renewable energy sources such as wind, solar, and hydropower power electrolysis, ensuring that green hydrogen production remains environmentally friendly. However, challenges related to water supply and purification, as well as storage and transportation, must be overcome for widespread adoption. Innovations in these areas, like utilizing brine from desalination and exploring ammonia-based transportation, are being developed to address these challenges. The integration of renewable power sources with electrolysis is crucial for maintaining the sustainability of green hydrogen production. Continued advancements in power storage, grid integration, and renewable energy efficiency are essential for making green hydrogen economically viable. As the demand for sustainable energy solutions grows, green hydrogen's ability to store and transport renewable electricity positions it as a key player in the energy transition towards a more sustainable future.