The Future of Green Hydrogen: A Deep Dive into Electrolysis Technologies
As the world transitions to clean energy, hydrogen has emerged as a key solution for decarbonizing industries and reducing dependence on fossil fuels. Produced through electrolysis using renewable energy, green hydrogen is poised to revolutionize the global energy sector. This article explores the latest advances in electrolysis technology, their benefits, challenges, and the path to a sustainable future.
Why Electrolysis for Green Hydrogen?
Electrolysis is a process that splits water (H₂O) into hydrogen (H₂) and oxygen (O₂) using electricity. When the electricity required for electrolysis comes from renewable sources like wind or solar energy, the resulting hydrogen is called “green hydrogen.” Green hydrogen is entirely carbon-free, unlike blue hydrogen (produced from fossil fuels with carbon capture) and grey hydrogen (produced from natural gas without carbon capture).
Different Electrolysis Techniques for Green Hydrogen
- Alkaline Electrolyzer (AEL): The AEL uses a liquid alkaline electrolyte (sodium or potassium hydroxide) and two electrodes separated by a diaphragm. It’s a proven technology with relatively low capital costs, suitable for large-scale use. However, its efficiency is relatively low, and response time is slow.
- Proton Exchange Membrane (PEM) Electrolyzer: PEM electrolyzers use a solid polymer electrolyte membrane to separate hydrogen and oxygen. They offer high efficiency, fast response time, compact design, and good integration with renewable energy. However, they’re expensive to manufacture due to the use of precious metals like platinum and iridium.
- Solid Oxide Electrolyzer (SOEC): SOEC operates at high temperatures (700–1,000°C) and uses a solid ceramic electrolyte. It has relatively high efficiency and good integration with industrial processes, as well as the ability to recycle waste heat. However, high temperatures can lead to rapid degradation of the material, limiting its lifespan.
- Anion Exchange Membrane (AEM) Electrolyzer: The AEM electrolyzer combines features of AEL and PEM. It uses a polymer membrane to transport hydroxide ions, reducing the use of heavy metals and improving efficiency. However, the technology is still in its early stages, and there are issues with membrane stability.
Water Requirement for Electrolysis
The electrolysis process requires significant amounts of water. Specifically:
- PEM electrolyzer: 17.5 liters per kilogram of hydrogen
- Alkaline electrolyzer: 22.3 liters per kilogram of hydrogen
- Steam methane reforming (SMR) with carbon capture: 32.2 liters per kilogram of hydrogen
Hydrogen Production
Global electrolyzer production capacity is expected to reach 23 GW/year in 2023, with China accounting for 60%. Europe and the US will account for 20% and 16%, respectively.
Moving Forward
Investment in research and policies for green hydrogen is likely to increase in the future. Catalyst innovation, the use of artificial intelligence, and government policies will reduce electrolyzer costs. Globally, green hydrogen consumption is expected to increase significantly by 2030.
Electrolysis is at the heart of the green hydrogen revolution, providing an effective alternative for clean and sustainable energy. With the help of advanced technologies, policies, and investments, the path to a hydrogen-based future is being paved.
The Author Dilip Patil is Managing Director of Karmyogi Ankushrao Tope Samarth Co-op Sugar Factory, Ambad -Jalna. (Maharashtra)
