Historically, the mass production of green hydrogen has not been viewed as a viable alternative energy solution for our climate crisis. But recent technological advancements in proton exchange membrane (PEM) electrolyzers offer new avenues for long-term viability and present an intriguing opportunity for manufacturers. Experts have long deemed electrolyzers as a central technology for meeting our “carbon peak and neutrality” goals, but substantive investments have lagged due to high manufacturing costs. What these recent advancements demonstrate, however, is that the long-term viability of electrolyzers is closer than many realize. As it currently stands, electrolyzers last longer, operate more efficiently and cost less than at any point in the technology’s history. Although electrolyzers did not become a key device in large-scale green hydrogen storage until the 1990s, their emergence in the alternative energy market has led to many new research and development (R&D) investments. Moreover, with a 90% reduction in uninstalled capital costs over the last 20 years, advocates can now convincingly argue that electrolyzers are the key to a sustainable energy future.
Advancements in Electrolyzer Technology
There have been a few important advancements made in electrolyzer technology. Improvements include thinner membranes, less precious metals, and optimization of designs. Implementation of Thinner Membranes. Why are thinner membranes so important? For starters, experts have speculated that thinner membranes allow electrolyzers to produce 150% more hydrogen or run at 10% lower energy consumption than traditional designs. This is due to the fact that thinner membranes reduce the overall distance protons have to travel across the porous transport layer (PTL). Accordingly, thinner membranes are responsible for faster ionic transportation and an increase in overall production. The most efficient electrolyzer design, however, combines thinner membranes with the implementation of perforated titanium sheets instead of conventional felt materials. Manufacturer investment in PTL has led to the creation of titanium PTLs (Figure 1, titanium sheets) as thin as 0.010″ that allow for lower oxidation rates, smaller footprints, and better resistance to bending and cracking. With this combination, PTLs can provide better thermal/electrical conduction and mechanical support, along with pathways for both reactant liquid water delivery to the catalyst layer and effective gas removal from the reaction sites to the outlet.
1. Porous transport layers (PTLs) from Mott are preferred in electrolysis applications due to an ultra-smooth design resulting in improved catalyst utilization and extended stack lifetime. Courtesy: Mott Corp. Reduced Precious Metal Coatings and Catalysts. Given the critical importance PTLs play in electrolyzer efficiency, limiting PTL deterioration is essential for manufacturers. Both the passivation of titanium and corrosion are limited by precious metal coatings that protect the electrolyzer. However, these coatings are often treated with platinum group metals, and this generates significant costs. As a result, any attempt to ensure electrolyzer economic viability necessitates a different coating strategy—and this requirement has helped to drive titanium sheet development. This solution has led to an enormous impact on manufacturing. A recent study found that thin layers of iridium can be sprayed on titanium PTLs, thereby eliminating the need for platinum group metal coatings. One key benefit of this approach is improved electrical conductivity at a cheaper price point. Ultimately, with reduced-iridium coatings, PEM electrolyzers have become significantly more cost effective. Optimization of Cell Design. Cells are critical for effective electrolyzer processes because they directly contribute to an electrolyzer’s total volume of hydrogen gas storage; the more cells manufacturers can stack atop one another, the larger the output. Optimizing cell design, therefore, means making the cell processes themselves more efficient as well as bettering cell interactions in the stack. Research teams have been working to optimize cell composition, leading to new and innovative designs. On the one hand, grooved electrode structures have been proven to provide up to 50% higher performance than existing electrode designs while also improving the cell’s overall durability. On the other, research has shown that cell transport can be improved with novel alkaline water-splitting electrolyzers. In fact, there is a case to be made that the biggest improvements left to be made with electrolyzer production lies with further cell design optimization.
More Green Hydrogen Coming Soon
In conclusion, the future of mass-production of hydrogen is closer than many people recognize. Currently estimated at $185 billion, the green hydrogen market is set to increase by more than 600% over the next 25 years. This anticipated growth is reflective of the role green hydrogen is set to play in our energy future as well as anticipated reductions in electrolyzer costs (a crucial selling point for manufacturers). However, this growth would not be possible without the improved efficiency and extended lifespans that have been achieved with recent electrolyzer advancements. Electrolyzers may have the most hidden potential of any green energy technology—the only question is which manufacturers are willing to capitalize. —Mott Corporation contributed this article.
