Water Supply via Desalination: An Imperative for Green Hydrogen Production
Amidst the evolving landscape of sustainable energy, hydrogen emerges as a potential game-changer. However, while much attention is given to the electricity required for hydrogen production, another essential component often gets sidelined: water.
Water: A Key Ingredient in Hydrogen Production
To produce hydrogen, a stoichiometric water demand of 8.9 kg H2O per kg of H2 exists. Factors such as water loss during fine purification, and the water contained in the saturated hydrogen and oxygen post-electrolysis, mean that the initial freshwater demand hovers around 15 kg H2O per kg H2. However, this demand is influenced by several variables including the technology supplier and water quality.
Sustainability beyond Hydrogen
A truly green hydrogen production doesn’t stop at zero carbon emissions. Water, as a dwindling resource in many parts of the world, demands careful management. Sustainable hydrogen production should safeguard against the adverse effects of water consumption on local environments and communities.
An analysis showcasing the global aridity index by Zomer et al. presents a revealing picture. Countries blessed with high humidity, such as Colombia, Brazil, and Ukraine, can rely on existing water grids. For these regions, water costs are assumed to be around 2 EUR per m³ of H2O. However, the story changes for countries in arid zones like Algeria, Australia, India, Mexico, and others. Here, a solution emerges from the seas.
Turning to Desalination: A Viable Solution
For countries grappling with water scarcity, desalinating seawater offers a potential lifeline. The dominant technology in this field is seawater reverse osmosis (SWRO). Its widespread adoption can be attributed to its minimal electrical power demands and no necessity for thermal energy.
| Parameter | Value | Unit |
| Specific energy consumption | 3.6 | kWh/m³ |
| CAPEX | 1,640 | EUR/(m³*d) |
| OPEX | 128 | EUR/(m³*d)/yr |
| Lifetime | 30 | years |
| TRL | 9 | – |
Despite the prowess of SWRO, challenges loom large. The most pressing issue is the disposal of brine, a by-product of desalination. Without careful management, brine can wreak havoc on underwater ecosystems. Thus, ensuring an environmentally-friendly dispersal of brine is of utmost importance.
Conclusion
As the world leans into a sustainable future, the intricate balance between energy, water, and environment becomes paramount. Ensuring an adequate water supply via methods like desalination not only propels hydrogen production but also aligns with the broader vision of a sustainable tomorrow.