Clean Hydrogen: A systematic review of technoeconomic aspects, production, transition policies and potential in the Brazilian and global scenario

Greenhouse gas (GHG) emissions are one of the major global challenges, intensifying the climate crisis and demanding sustainable solutions for the energy transition. Clean hydrogen (Hₗ) emerges as a promising alternative, aligned with the Sustainable Development Goals (SDGs). This article presents a systematic review, following PRISMA guidelines, on the advances, challenges, and opportunities of Hₗ, focusing on four categories: techno-economic aspects, production methods, transition policies, and the potential of clean hydrogen. The analysis covers studies from databases such as ScienceDirect and Web of Science, addressing regulatory strategies, technological innovations, and economic viability. Results indicate that, despite its high energy density and low environmental impact, Hₗ faces significant barriers, such as high costs and technological limitations. It is concluded that joint efforts in research, regulation, and investments are crucial to accelerate its implementation as a solution for global energy sustainability.