The report "Green Hydrogen Supply: A Guide to Policy Making" by IRENA provides an overview of the potential of green hydrogen as a clean and sustainable energy source. The report highlights the importance of policy making in promoting the widespread adoption and sustainable use of green hydrogen. It discusses the current state of the green hydrogen market, the potential benefits and challenges of green hydrogen, and the policies and measures that can be implemented to support its development. The report also provides case studies of countries that have successfully implemented policies to promote green hydrogen. Overall, the report serves as a valuable guide for policymakers and stakeholders interested in promoting the adoption of green hydrogen.