E. Greenbaum
GTA, Inc.,
United States
Keywords: gigawatt-scale hydrogen production, utility grid balancing, offshore wind
Summary:
Please see the uploaded PDF file for literature citations and supplemental information. Background: GTA is a prototype R&D engineering company focused on integrating offshore wind and ocean energies with subsea electrolytic hydrogen and oxygen production. Subsea electrolytic hydrogen production and storage systems are the safest approach to gigawatt-scale clean hydrogen. All unit operations needed for subsea electrolytic hydrogen production and storage are already being performed by the workforce of the offshore gas and oil industry, albeit in different contexts. Objectives: Subsea hydrogen LDES systems are fire and explosion proof. Combustible oxygen is not accessible. The hazards of above-ground PEM electrolyzer hydrogen production and storage systems are documented. Brophy has provided guidance for a category of electrolyzers that are needed: “Electrolyzers need to live outside. Equipment that is designed with its own all-weather enclosure and that solves the hazardous area classification, ventilation and safety issues within its own footprint is enormously valuable.” , The objectives of the presentation are to provide examples of these electrolyzers. Methodology: A lab-scale TRL 4 proof of concept electrolyzer was designed and built as previously described. Smooth nickel 200 ribbon wire electrode arrays were positioned on opposite sides of a porous polyethylene sheet that separated the cathode and anode compartment of the electrolyzer. The electrolyzer housing was fabricated from machined cast acrylic. The TRL 4 electrolyzer was validated at NREL under the DOE H2@Scale CRADA program. Key findings: Native purity of hydrogen emerging from the cathode compartment was 99.65%. This is sufficient purity for many industrial applications. A single oxygen removal step lowered the background oxygen concentration to 9.4 ppm and brought the purity of the hydrogen close the SAE J2719 fuel cell standard. Implications and Significance: The electrolyzers were constructed from relatively inexpensive commodity materials that are sold worldwide in competitive markets. Supply chain issues are unlikely to be problematic. Thermoplastic polymers are recyclable and can be manufactured using rapid digital automation techniques.