Increasing Hydrogen Production Efficiency Through Cell-Level Voltage Measuring 

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Takeaways 

• Stack-wide voltage averages conceal performance differences across individual cells. 
• Spatial analysis of cell voltages reveals differences in cell component performance and fluid dynamic inefficiencies. 
• Component validation in industrial environments improves procurement and design choices. 
• Real-life measurement complements simulations by providing data for model calibration. 
• Cell voltage measurement systems support maintenance and safety protocols by finding anomalies early. 

About the author 

Pino Kirsch is a mechanical engineer with a master’s degree in Energy Engineering from KTH Royal Institute of Technology in Stockholm. Previously he has worked with different applications for hydrogen usage in an automotive context as well as with large-scale electrolysers for a green steel plant. At Stargate Hydrogen Pino works as Stack Development Engineer, overseeing the performance development of the stack including simulation and testing activities. 

Increasing hydrogen production efficiency 

Increasing hydrogen production efficiency is often discussed in terms of large-scale system optimisation — upgrading power supplies, or redesigning gas separators. However, most practical and impactful opportunities lie within the electrolyser stack itself.  

Specifically, by closely observing how each individual cell performs.  

Electrolysers are made up of many cells connected in series, and while the system’s average voltage can indicate overall performance, it often masks meaningful differences between cells. A poorly performing cell can bring down overall stack efficiency. 

Cell-level voltage monitoring offers engineers a precise lens through which to evaluate the Increasing hydrogen production efficiency and make informed design and procurement decisions. This method shifts the focus from average performance to actual performance — a critical distinction in a field where efficiency improvements translate directly into lower costs and longer system lifetimes. 

Understanding the Diagnostic Value of Individual Cell Monitoring for Increasing Hydrogen Production Efficiency

Increasing hydrogen production efficiency is the ultimate goal, but choosing traditional stack monitoring methods is not the ideal approach. These methods only rely on calculating the average voltage by dividing the total voltage by the number of cells. While this provides a basic snapshot of efficiency, it assumes homogeneity across the stack — a rare occurrence in operational systems. 
 

Electrolyser cells are subject to variable conditions such as uneven pressure distribution, uneven electrolyte supply, shunt currents, and thermal gradients. These variables influence performance at the cell level, and when hidden behind an average, they prevent detection of problems. 

When increasing hydrogen production efficiency, monitoring each cell individually enables the detection of underperforming units, identification of the root causes of voltage drift, and early warning signs of impending failure. For example, localised increases in cell voltage often indicate higher resistance, which can be caused by issues such as catalyst deactivation, membrane blocking, or minor structural defects. By isolating these behaviours to specific cells, operators can respond proactively, adjusting system parameters or initiating maintenance before the inefficiency spreads. 

Fictitious Example: 
At a medium-scale hydrogen pilot facility, a gradual drop in efficiency was initially dismissed as part of system variability. But when a new CVM (Cell Voltage Monitoring) system was introduced, it quickly revealed that one cell had been operating consistently at a higher voltage, suggesting localised damage. Further inspection confirmed a particularly bad catalyst adhesion, which had increased the cell’s overpotential. Catching the issue early prevented a cascade of degradation across the stack and avoided the costly replacement of adjacent cells. 

Spatial Variation in Stack Performance and Its Engineering Implications 

Performance inconsistencies across the stack are not random; they often follow spatial patterns tied to the stack’s mechanical design and fluid dynamics. In alkaline electrolysers, cells closer to the electrolyte inlet typically have a particularly low resistance to fluid flow, resulting in consistently good electrolyte supply, while cells further downstream can experience inconsistent and reduced electrolyte supply. Similarly, structural factors such as cell compression and components’ manufacturing tolerances introduce variations that affect how evenly fluid and electric fields are distributed. 

These performance variations are particularly problematic because they can skew system behaviour in ways that are difficult to predict using simulations alone. For example, end-plate effects — at the electrolyte manifold’s inlet and dead-end, respectively — can affect electrolyte supply to the cells and enhance performance at the stack edges, while interior cells may suffer from more volatile electrolyte access. When engineers who seek Increasing hydrogen production efficiency only monitor the stack as a whole, these patterns remain invisible. By analysing individual cell voltages as a function of stack position, it's possible to detect these design-related inefficiencies and implement changes that improve uniformity and total efficiency. 

Supporting Scale-Up: Aligning Laboratory Models with Industrial Reality 

In the quest for increasing hydrogen production efficiency, cell-level voltage monitoring becomes an essential tool. By collecting real-world data from full-size stacks, engineers can test whether design assumptions hold under load, identify which cell positions are most vulnerable to performance drift, and refine stack architecture accordingly. This data also enables a feedback loop between R&D and engineering teams, allowing hypotheses from lab environments to be tested and adjusted based on actual field performance. It supports more realistic modelling and helps bridge the divide between controlled experiments and commercial deployment. 

Component Testing Under Real Operating Conditions for Increasing Hydrogen Production Efficiency

Material and component selection is one of the most decisive factors in determining an electrolyser’s efficiency, durability, and cost-effectiveness. However, laboratory testing, though valuable, rarely replicates the full range of stresses that materials encounter in a functioning stack. Lab setups operate at a much smaller scale and under precisely controlled flow, temperature, and pressure, minimising the unpredictable variables that exist in real-world systems. This creates a gap between theoretical performance and real-world reliability. 

Cell-level monitoring bridges that gap by allowing multiple material variations to be tested simultaneously within an industrial stack in one single test or during live operation. For instance, an operator might deploy alternating membrane types across the cells, using voltage data to track which materials maintain performance under operational loads, thermal cycles, and fluctuating flow rates. This method offers both comparative and contextual performance data, giving teams confidence in selecting materials that will perform well in real-world operations. 

Real-World Data vs. Simulation: A Balanced Approach 

* Due to computational limitations, it is not reasonably possible to simulate the real operation of a full-scale stack. 

Increasing hydrogen production efficiency via simulations is a powerful approach for first designs, concept exploration, and predicting behaviour under new conditions. However, without calibration from real measurements, their predictions can diverge from actual performance. Cell-level data provides the empirical anchor allowing digital twins and other simulation tools to deliver more accurate, context-sensitive results. Together, they enable more confident design decisions while reducing the need for repeated physical prototyping. 

Learn how Stargate Hydrogen uses simulations to improve stack efficiency. 

Evaluating Cost-Performance Trade-Offs with Data-Driven Precision 

One of the most difficult aspects of electrolyser system design is determining whether a component’s added cost is justified by its performance gain. Trying to reach Increasing hydrogen production efficiency without detailed performance metrics, teams often rely on lab results or supplier claims, which don’t reflect long-term behaviour under industrial conditions. Cell-level monitoring allows organisations to gather the type of long-term field-based data that reveals not just short-term efficiency, but also long-term reliability.  

This enables more sophisticated decision-making, such as calculating lifecycle cost versus output, or finding the break-even point for higher-priced materials. Procurement becomes less about assumptions and more about evidence, reducing both technical and financial risk in deployment. 

Managing Ohmic Losses and CVM Implementation for Increasing Hydrogen Production Efficiency

Ohmic losses refer to voltage drops due to the inherent resistance of the system’s conductive components, such as electrodes, bipolar plates, contact resistances and the stack terminal connections. These losses accumulate across the stack and distort the apparent voltage of the cells. Without cell-specific measurement, it becomes difficult to differentiate between systemic loss and genuine inefficiency at the electrochemical level. CVM (Cell Voltage Monitoring) systems solve this by isolating and measuring each cell independently, filtering out external losses. 

The technical implementation of CVM systems requires careful attention. They must remain reliable in chemically aggressive environments and have very high measurement accuracy. Modern CVM setups often resemble simplified battery management systems, with modular architecture, integrated data logging, and real-time analytics. This makes them not only diagnostic tools but also control instruments that can interact with broader plant automation and safety systems. 

Enabling Maintenance and Protecting Against Failure 

But not everything is about increasing hydrogen production efficiency; companies are also seeking reliability, and preventive maintenance relies on early warnings, and voltage data provides a key signal. A slow, progressive rise in a cell’s operating voltage might point to expected catalyst degradation, while sudden spikes can indicate defective electrical contacts between cell components or extensive contamination. When monitored continuously, these anomalies become triggers for inspections, maintenance scheduling, or automated system interventions. 

Final Thoughts: Why Cell-Level Precision Matters 

Hydrogen efficiency isn't about a single metric — it's the product of dozens of interdependent design and operational decisions. Monitoring voltage at the individual cell level brings clarity to these decisions, replacing assumptions with evidence. It enables engineers to understand stack behaviour in full complexity, supports smarter material choice, refines simulation accuracy, and reduces operational risk. The benefits extend from the R&D lab to the production floor and the operation phase, and ultimately shape the economic viability of green hydrogen technologies. 

If you would like to know more about increasing hydrogen production efficiency and the performance of Stargate Hydrogen’s products, get in contact with our team of experts, who will promptly answer your questions.