Green hydrogen revolution: Advancing electrolysis, market integration, and sustainable energy transitions towards a net-zero future

Green hydrogen is emerging as a key driver in global decarbonization efforts, particularly in hard-to-abate sectors such as steel manufacturing, ammonia production, and long-distance transportation. This study evaluates the techno-economic and environmental aspects of green hydrogen production, storage, and integration with renewable energy systems. Electrolysis remains the dominant production method, with efficiency rates ranging from 70 to 80 % for Alkaline Electrolyzers (AEL), 75-85 % for Proton Exchange Membrane Electrolyzers (PEMEL), and up to 90 % for Solid Oxide Electrolyzers (SOEL). Capital costs are steadily decreasing, with AEL costs falling from $1200/kW in 2018 to $800/kW in 2024, while PEMEL costs are projected to decline to $600/ kW by 2030. Green hydrogen significantly reduces carbon emissions, with a footprint of 0.5-1 kg COQ per kg of HQ, compared to 10-12 kg for gray hydrogen and 1-3 kg for blue hydrogen. Its potential to cut global COQ emissions by 6 gigatons annually by 2050 underscores its role in climate action. However, its high water demand-approximately 9 liters per kilogram of hydrogen-necessitates efficient management strategies such as desalination and recycling. Economically, green hydrogen is becoming more competitive, with its levelized cost decreasing from $6/kg in 2018 to $3-4/kg in 2024, and projections indicating a further drop to $1.50/kg by 2030. Global investments exceeding $500 billion in 2024, along with major projects like Saudi Arabia's NEOM Green Hydrogen Project and Australia's Asian Renewable Energy Hub, are accelerating adoption. Policy frameworks such as the EU Hydrogen Strategy and the U.S. Inflation Reduction Act further support deployment. Despite progress, challenges remain in infrastructure, storage, and regulatory frameworks, necessitating continued innovation and international collaboration. Green hydrogen aligns with key Sustainable Development Goals (SDGs), including SDG 7 (Affordable and Clean Energy), SDG 9 (Industry, Innovation, and Infrastructure), and SDG 13 (Climate Action). As the world transitions to a low-carbon economy, green hydrogen presents a transformative opportunity, contingent on sustained technological advancements, investment, and policy support.