With the confirmation of 11 new UK projects in the recent Budget, green hydrogen’s potential to play a pivotal role as a renewable energy source for the future is clear for all to see. However, despite the clear opportunities, the shift towards more wide-scale commercial applications means the importance of organising and optimising safety is paramount.
According to the International Energy Agency, low-emission hydrogen production is rising fast from a baseline of below one megatonne (Mt) in 2024, potentially reaching 49 Mt by 2030. However, the use of hydrogen as a fuel source is nothing new. Back in the 1960s NASA was faced with two fundamental issues during the space race; the propulsion needed to get humankind off of the Earth’s surface, and the power required to keep astronauts and the space module alive for the duration of the space mission.
They turned to hydrogen as the solution to both – not only does the gas pack an enormous punch in terms of propulsion, its lightweight nature made it ideal in the development of NASA’s first practical fuel cells that powered the first Apollo missions.
It has since gone on to find use in a multitude of industrial applications in energy intensive industries such as oil and gas, petrochemicals and refining. However, the drive for net zero means that we are now standing on the brink of a hydrogen-powered future and as such, the whole business model is changing; moving towards mass generation and distribution, and use in transmission and transportation. Therefore, hydrogen is getting closer to consumers at the point of use.
“Hydrogen is going to start appearing in places outside traditional industrial use and more within the commercial and domestic landscape”, commented Steven Elliott, Senior Director of Triconex Safety and Critical Control, Schneider Electric.
This shift in the hydrogen landscape means that an end-to-end approach to safety in the green hydrogen value chain is vital. Incidents around hydrogen have occurred in the past at the industrial level and these can impact market growth and harm public trust.
Steven continued: “It’s very hard to trust hydrogen because you can’t smell, see or taste it, so it’s hard to know whether it’s even there. In addition, when you look at the flammability and ignition range of hydrogen, it’s very easy to ignite. For example, a small 9V battery would be enough energy to ignite hydrogen if it finds its way out of the process. It’s flammability range is far higher than propane or gasoline and its minimum ignition point is much lower.”
Not only that, assumptions can be a clear and present danger when it comes to hydrogen and a failure to address knowledge gaps can result in incidents and setbacks. Because it has been around for some time, there is a familiarity with hydrogen and an associated knowledge can sometimes be taken for granted.
Steven added: “As a safety professional, the worst thing we hear are assumptions. Not everyone knows hydrogen. And as its use extends into the commercial and domestic market, that brings with it a fear. Like every gas, hydrogen has its own unique properties, and if you don’t understand it, you can’t control or keep it safe. People are very quick to make assumptions about the use of hydrogen without really understanding its properties.”
Scaling up hydrogen production
Typical equipment used in hydrogen generation – whether it be in small modular units or increasingly popular, larger plant sites – includes electrolysers, compression facilities, switchgear and transformers, rectifiers etc, which means a number of hazards are present relating to pressure and temperature.
Because hydrogen is 14 times lighter than air, it’s safe to assume that, should any gas escape, it will travel upwards and out of harm’s way, right? Wrong. Because the gas is under pressure, it will first travel out before it travels up, and its buoyancy does not exert significant influence until the gas has slowed sufficiently so that the momentum forces caused by the pressure have weakened.
Therefore, a significant proportion of any escaped hydrogen cloud can travel beyond the boundaries of the congested region of a facility. Not only that but hydrogen causes metal embrittlement. It’s therefore the enemy of steel and attacks it, and a mere pinprick combined with high pressure can cause jet fires.
“It’s also important to consider the blast radius” Steven continued. “It is estimated that one kilogram of hydrogen is equivalent to about 50 tonnes of TNT. In that context you can see the scale of magnitude, so understanding the risks and threats are crucial – whether that’s from the point of view of the consumer, buyer, manufacturer or engineering company – the race is on.”
As the way in which hydrogen is used, consumed and transported changes to a more domestic model, the location of production becomes a key consideration. A process hazard analysis and electrical hazard analysis can therefore identify risk, likelihood and consequence, and what mitigation measures can be put in place. Unfortunately, in addition to process and electrical hazards, the cyber threat is all too real in the modern world, meaning that threats are no longer confined within the facility.
Where a hydrogen facility is located matters. For example, over 40 new hydrogen buses have recently been deployed in Crawley, West Sussex, at a cost of £24m. Part of the infrastructure included a permanent refuelling station (the largest of its kind in the UK), capable of producing 1,600kg of hydrogen per day.
However, the Health and Safety Executive (HSE) stated that its location represented, ‘Sufficiently high risks to the surrounding populations, including a nearby school.’ “This means they can only use a small capacity of that refueling station” added Steven. “So, where you build is also going to be important, especially when you consider the move to more domestic market spaces.”
Another key consideration within the hydrogen process is the use of electrolysers; which use electricity to split water into hydrogen and oxygen, and are critical for producing low-emission hydrogen from renewable or nuclear electricity.
“These are tricky little rascals” Steven continued. “The reason I say that is because you’ve got two things you really don’t want – an ignitable gas with a very low ignition point right next to a high electrical load with an ability to cause a spark.
Increasing safety and reducing risk
With hydrogen set to play a pivotal role as a renewable energy source for the future, any investment must be underpinned by a complete approach to risk prevention that protects a facility at every stage in the lifecycle and in the value chain. As such, Schneider Electric is combining this risk assessment with the use of digital twins which enables rigorous testing and brings data sets from across process and electrical systems together for insight into correlations and behaviours. Once applied within hydrogen facilities this approach can then be applied as an end-to-end model across the whole energy supply 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 its full lifecycle. With hydrogen’s highly flammable nature, low ignition energy, metal embrittlement and small molecular size, construction must include purpose-built components, including Ex-rated systems and materials that prevent the risk of leakage, as well as digital monitoring and control systems that will react to high or low temperatures, levels, flows and pressures.
Steven added: “At Schneider Electric, we believe that the transition to green hydrogen must be accompanied by a comprehensive approach to risk management. By integrating advanced digital twins into our operations, we can ensure that every phase of the hydrogen production lifecycle is optimised and safeguarded. This innovative strategy not only enhances operational efficiency but also aligns with our vision for a decarbonised world, paving the way for a cleaner, greener future.”
Find out how Schneider Electric organises and optimises safety in hydrogen processes by watching the on-demand webinar here. The webinar shows how adaptation in the age of new energies is the key to driving a greener future.
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