Advancements in green hydrogen production: A comprehensive review of prospects, challenges, and innovations in electrolyzer technologies

Abstract

The global energy demand is projected to grow by 1.3 % annually until 2040, driven by population growth, economic expansion, and technological advancements. Fossil fuels, which currently account for 85 % of global energy consumption, are the primary contributors to greenhouse gas emissions, with over 36 billion tons of CO₂ released annually. In response, green hydrogen has emerged as a promising solution for decarbonizing energy systems, offering a sustainable alternative to fossil fuels. Produced through water electrolysis powered by renewable energy sources, green hydrogen is poised to play a pivotal role in the transition to a low-carbon economy. This review provides a comprehensive analysis of the current state and future prospects of green hydrogen production, focusing on advancements in electrolyzer technologies, including Proton Exchange Membrane (PEM), Alkaline Water Electrolyzers (AWE), and Solid Oxide Electrolysis Cells (SOECs). The review highlights key innovations in electrode materials, ultrasonic field applications, machine learning (ML) optimization, and renewable energy integration, which collectively enhance the efficiency, scalability, and cost-effectiveness of hydrogen production. Additionally, the economic and environmental implications of hydrogen production methods, categorized by their “color” (green, blue, grey, brown, and black), are critically evaluated. Prominently, large-scale initiatives such as HyDeal España, the NEOM Green Hydrogen Project, and H2H Saltend exemplify the global momentum behind green hydrogen deployment. Despite significant progress, challenges such as high costs, material durability, and the intermittency of renewable energy sources remain barriers to widespread adoption. This review highlights the importance of continued research and development, supportive policies, and technological breakthroughs to overcome these challenges and accelerate the global transition to a hydrogen-based energy economy. By addressing these issues, green hydrogen can become a cornerstone of sustainable energy systems, contributing to climate change mitigation and energy security.