Direct Sea Water Electrolysis
Green H2 consumes large amount of DM water. Considering challenges of global water security, works are being carried out for development of sea water electrolysis.
Rationale
Green H2 consumes large amount of DM water. For National Green Hydrogen Mission Target (5 MMTPA), approx. 45 MCM (Million Cubic Meter) DM water shall be required. Considering challenges of global water security, sea water electrolysis may provide the much-desired solution. Accordingly, different methodologies for using sea water for hydrogen production need to be explored.
Brief About the Technology/Works being carried out
Studies are being planned by ET&PR group along with CSIR for the technologies given below. MOU in this regard has been signed with CSIR-CMERI and CSIR-NCL. After successful demonstration on a lab scale, the technologies shall be considered for implementation in Pilot AEM plant at NTPC Dadri.
- Technology-1: Direct sea water electrolysis by electrolyte engineering. The technology is based on addition of suitable inhibitor (developed indigenously by CSIR) in the existing alkaline or AEM electrolysers (having alkaline environment) to inhibit chlorine evolution and address other challenges associated with sea water electrolysis.
- Technology-2: Sea water electrolysis by directly coupling alkaline/AEM electrolyser with Forward Osmosis (FO) module
Uniqueness/Benefits of the Project
- Technology-1:
- Existing electrolysers can be used for direct sea water electrolysis by addition of indigenously developed inhibitor.
- No change in design of existing electrolysers shall be required.
- No energy required for desalination of sea water.
- Technology-2:
- Direct coupling of draw solution (KOH) of FO modules with existing alkaline/AEM electrolyser shall result in facilities/infrastructure requirement and less power consumption for water treatment.
- Indigenous polymer membrane developed by CSIR is expected to reduce the power consumption as compared to other FO technologies.
Future Prospects
There is huge potential for direct sea water electrolysis considering challenge of water requirements. Once proven, both the technologies can be used with existing electrolysers. Hydrogen hubs/bunkers shall be setup at ports, thereby providing another opportunity area for the technologies