CLEAN ENERGY HOLISTIC SAFETY FOR HANDLING HYDROGEN
Hydrogen is quickly becoming a
cornerstone of the global energy transition towards cleaner sources, but its full potential can only be realised with a holistic approach to the safety at
production facilities. Steven Elliott, Senior Director, Triconex Safety and Critical Control - Schneider Electric, explains more...
A
s the world pursues a future powered by clean energy, green hydrogen stands out as a key player in global
decarbonisation. While this is driving many new market entrants racing to bring hydrogen offers to the market, it also brings unique safety concerns that only require one small incident to potentially stall the hydrogen economy. Hydrogen is highly flammable, can embrittle
metals and has a small particle size that makes it difficult to contain without leakage. To overcome this, any investment in hydrogen should sit alongside a holistic approach to risk prevention that protects a facility at every stage in the lifecycle. This approach to safety ensures, for emerging companies and established businesses, the lessons of the past are not forgotten while addressing a new generation of threats that come from modern technology that will support offers for years to come. When NASA embarked on the mission to
send a man to the moon it turned to hydrogen as the solution for propulsion and stored energy. In fact, there is not a commercial fuel cell today that doesn’t owe some debt to NASA’s early exploration of the technology. Since then, hydrogen has been used as a fuel and energy solution in a number of applications, providing industry with the experience of managing hydrogen risks. But as investment grows and more industries become reliant on hydrogen, any
small incident can have a drastic impact on the entire value chain.
Incorporating safety in a hydrogen production facility starts with ensuring that safety is not an afterthought but an integral element of the design. The more time and effort invested during this stage, the safer a plant is throughout the full lifecycle. A process hazard analysis (PHA) or a hazard and operability study (HAZOP) are two structured methods that gather a team of experts to break the system down, highlight possible deviations, and document the causes and consequences to mitigate risk. Hydrogen’s highly flammable nature and low ignition energy means construction must include purpose-built components, including materials that prevent the risk of leakage. With properly certified equipment (explosion proof equipment, leak detection, real-time monitoring), facilities can minimise the likelihood of a spark by specifying effective bonding and grounding, using non-sparking materials wherever possible like plastic fan blades.
Once a facility is in operation, safety procedures and protocols should be continually reviewed alongside any new technology. This requires continuous oversight of hydrogen processes and constant attention to ATEX zones. Wireless temperature sensors can be fitted to the electrical bus bars, and thermal imaging can be used to find hot spots to reduce the risk of electrical fires or arc flash. While the risk can never be zero, risk management reduces it to an acceptable level by taking steps to reduce the likelihood of an incident occurring.
The typical hydrogen production plant consists of two key elements, the electrolyser itself and the supporting balance of plant equipment such as batteries, water, air, compressors, storage, and firefighting systems. The risks associated with both parts
38 DECEMBER 2024/JANUARY 2025 | PROCESS & CONTROL
are represented by high or low temperature, level, flow, and pressure. If an anomaly is detected or an emergency stop button is pressed, the control system should automatically bring the plant to a safe state. This includes cutting power to non-critical components such as compressors, activating ventilation systems and, release trapped volumes of gas in pipework. It should also raise an alarm to inform personnel.
But there are new threats, risks and hazards no longer limited to just the process. Cyber threats are now a factor of life. In 2023, the number of ransomware victims doubled compared to April 20221
. Cyber-crimes are
getting more frequent and more aggressive, requiring the same systemic approach to process hazards and mitigate risk. In the same way as a process HAZOP, a cyber-HAZOP breaks the system architecture down to a set of nodes to identify deviations and document the causes. An electrical-HAZOP does the same, highlighting deviations and documenting the consequences. Combining this risk assessment with the use of digital twins enables even more rigorous testing, as it brings all data sets together for insight into correlations and behaviours between the process and electrical systems. This represents a holistic safety approach to a hydrogen facility that can be applied as an end-to-end model of the green hydrogen production chain.
Ensuring system integrity is not just about keeping the hydrogen in the system, it’s also essential that the safety system and process control protection should work independently. This greatly reduces the risk of common causes of failure, as well as systematic failures that could affect the entire system. Physically separate systems with diverse technologies present the ideal way to protect overall safety. An overall process control system will bring the two domains of the process control
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