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Bolt Monitoring on PEM electrolysis stacks

With the surging demand for clean and efficient energy storage solutions, hydrogen has emerged as a promising candidate. This has led to a significant increase in the demand for PEM (Proton Exchange Membrane) electrolysis stacks, which play a crucial role in the production and storage of hydrogen. As the market for PEM electrolysers continues to expand, manufacturers have an exciting opportunity to capitalize on this trend.


Manufacturers looking to win (and retain) customers must be able to closely monitor a number of parameters in order to maintain the safety and performance of their electrolysers:

  • Hydrogen production can be dangerous – high temperatures, high pressures, and potentially explosive materials are all involved in production. Hence, the safety of electrolysers needs to be guaranteed.
  • PEM electrolysers can malfunction or lose efficiency in a number of ways, many of which are impossible to identify, evaluate, and track manually.
  • Multiple parameters need to be monitored closely to ensure that operations continue to run smoothly.


Read the in-depth article below to find out about the importance of the tie rods holding the stacks within the hydrogen electrolyser together and how the force operating on them can easily (automatically and economically!) be monitored. 

Bolt monitoring on PEM electrolyzers infographic - iso

How automated bolt monitoring makes PEM electrolysers more efficient than ever

Demand for hydrogen is on the rise across the globe, as the world finally begins to recognize the enormous potential of green hydrogen.  In fact, PwC predicts that demand will sit somewhere between 150 million and 500 million metric tonnes per year, depending on how fully governments and industries embrace green hydrogen as a clean energy source. 

Even if we don’t meet the upper end of that lofty prediction, that’s still a major boost in hydrogen production. A boom in demand for PEM electrolysis stacks is certainly on the way, too.

PEM electrolyzers can be temperamental beasts; the very nature of hydrogen production leaves your equipment vulnerable to malfunctions and inefficiencies. Many of those inefficiencies are almost impossible to identify, evaluate and track using purely manual processes. Uncovering an issue means putting parameters like pressure, temperature, and hydrogen production under constant, granular surveillance. 

One element in particular needs to be watched closely; the force operating on tie rods or bolts, which hold the stacks within a hydrogen electrolyser together. 

This need for detailed, accurate, real-time monitoring – and the difficulty of gathering this kind of information manually – is why PEM electrolyser manufacturers are exploring how advanced equipment and clever automation can get them the insight they need. 

Specifically, manufacturers are increasingly using force washers to monitor bolts and deliver information seamlessly to their PLC system. Before we discuss the specific technology, let’s explore why this kind of insight is essential for manufacturers. 

Common issues with PEM electrolysers

High temperatures, high pressures, explosive materials – hydrogen production can be a dangerous and volatile process. And PEM electrolysis stacks are vulnerable to a number of their own specific issues.

This is why manufacturers must absolutely reduce the possibility of explosions occurring. Especially when it comes to the tie rods that hold together the anode plates, cathode plates and membranes of the electrolyser. 

The exposure to high pressures and extreme temperatures means that the bolts tend to loosen over time so that energy begins to leak from the electrolyser. 

Monitoring the bolts manually would mean stopping production, an inefficient process that could only be conducted a few times a week at most. And, since it’s difficult for the naked eye to spot the signs that your electrolyser isn’t working efficiently, this laborious process still wouldn’t give you the insights you need. 

To really gauge the performance of your electrolysers and keep an eye on the status of the bolts, you’ll need to implement a form of automated, real-time monitoring. The kind of monitoring that allows you to identify problems as soon as – or even before – they occur. 

What does automated bolt monitoring for PEM electrolysers involve?

Force washers are load cells that are specifically designed for measuring clamping forces. Attach load cells to the bolts of your PEM electrolyser, and they’ll be able to constantly monitor the tension acting on the bolts. 

Of course, this information isn’t much use if you can’t access it or use it. That’s why force washers need to work seamlessly with your PLC, continuously gathering and transmitting data in real-time. With safety and efficiency hanging in the balance, you can’t afford to wait for long data transfer processes, which slow your reaction time and undermine the usefulness of the data.

Hydrogen renewable energy production - hydrogen gas for clean electricity solar and windturbine facility. 3d rendering.

Finding your perfect bolt monitoring solution 

There are a number of bolt monitoring solutions available on the market. When weighing up solutions, make sure you look for one that: 

  • Can perform well in harsh environments
    You can’t afford to have a force washer that crumbles under high pressures or temperatures. Ask any potential providers how they make sure their hardware is robust enough to stand the test of time.
  • Is cost-effective
    You’ll need to install many sensors – at least one per bolt – to gather the kind of data you need. If your force washers are too expensive, that will drive up costs rapidly. Of course, that doesn’t just mean you should go with the cheapest provider, since you don’t want to sacrifice quality or robustness in favour of savings. Instead, look for a provider who provides high-quality sensors that can adapt to a wide range of different use cases; that way, you’ll be able to save costs by re-using force washers for other applications.
  • Covers the complete measurement chain
    To really see the benefit of automated bolt monitoring, you need to see the data your force washers gather quickly – without wasting time with long data transfer processes or worrying about lost data. Look for a partner who can support you with the entire process of measurement, from sensors to electronics and PLC integration, so you can keep sight of the whole picture effortlessly. 

Optimise from every angle with HBK 

The condition of bolts might be one of the most crucial contributors to the performance of a PEM electrolyser, but it’s definitely not the only area that needs to be monitored. 

To truly optimise the performance of your PEM electrolysers – and show customers you’re conscientious about their ROI and their wellbeing – you’ll need to analyse their operations from every angle. Everything from pressure to temperature and the efficiency of hydrogen production can – and should – be carefully tracked. 

Building a robust, complete network of sensors to measure conditions inside your electrolysis stacks is an easy way to stand out from the competition and take the performance of your equipment to the next level. In other words, it’s an essential tool for any company looking to take advantage of hydrogen’s rise in popularity and win more customers with quality equipment.

At HBK, we’re helping companies around the world keep their PEM hydrogen electrolysers running smoothly, safely and efficiently. 

How do we do it? We use our: 

  • Extensive expertise in the hydrogen industry – Our engineers know what it takes to make testing and measurement simple and effective across the whole value chain of hydrogen production. 
  • End-to-end support – We’ll help ensure that your sensors, electronics and PLC work seamlessly together, putting the full picture of your performance at your fingertips. 
  • Expert assistance – We’re here to make sure you get the most accurate picture from your equipment. From setting up your sensors to analysing your results, we’ll offer expert advice and support from day one. 
  • Low TCO - HBK sensors are built to deliver excellent insights, without breaking the bank. And they’re flexible too, which makes it easy to remove your sensors and use them again for different projects and different areas of production, instead of wasting time and money on installing new equipment. 
  • Total reliability - We build our sensors to withstand the harshest environments – including those inside PEM electrolysis stacks. So you can cut down on maintenance time and analyse your data, completely confident that your sensors are always accurate and running smoothly. 


At HBK, we specialise in helping our customers build outstanding products – like hydrogen electrolysers – with robust, flexible, efficient equipment.  Equipment that brings the physical and the digital worlds together to deliver deeper insights and support data-driven decision-making.