Hydrogen, often hailed as the fuel of the future, holds immense promise for a clean energy transition. However, like any energy source, it comes with certain risks that must be understood and mitigated.
Despite its environmental benefits, hydrogen poses inherent safety challenges due to its unique properties. Being colourless, odourless, and highly flammable, hydrogen can be difficult to detect, leading to potential ignition hazards. Additionally, when stored under pressure, hydrogen can cause explosions if not handled properly. Hydrogen embrittlement, which weakens metals and materials, is another significant concern.
The history of energy transitions reminds us that the adoption of new energy sources is often accompanied by challenges. Just as the early use of fossil fuels faced numerous accidents that shaped today’s safety measures, the safety protocols for hydrogen are also being shaped by lessons learnt from past incidents. Investigation reports are crucial resources for analysing root causes and implementing preventive measures.
In previous blogs, we have discussed the risks associated with hydrogen operations and storage in greater detail and showcased the analysis of these risks.
In this blog, we examine notable incidents and extract valuable lessons to ensure the safer adoption of hydrogen technologies. Understanding these risks is essential for promoting the safe and effective use of hydrogen as we move towards a cleaner energy future.
These incidents underscore the importance of understanding and preparing for the unique challenges posed by hydrogen as a new energy carrier.
Hydrogen storage tank explosion in electrolysis unit, Gangneung, South Korea, 2019
- Incident summary
The tragic accident in Gangneung, South Korea, serves as a reminder of the inherent risks associated with hydrogen storage and the importance of strict safety measures.
The incident involved an explosion in a hydrogen buffer tank at a testing site, where renewable hydrogen was being experimentally generated in a water electrolyser powered by solar panels. The explosion resulted in the loss of 2 lives, injured 6 people, and caused significant damage to buildings within a 100-metre radius from the tanks.1
- Cause
Preliminary results from the legal investigation indicate that the explosion was caused by a static spark in the hydrogen buffer tank, combined with the presence of oxygen in the hydrogen stream.
This oxygen contamination occurred due to a malfunctioning separation membrane in the electrolyser, which allowed oxygen to diffuse into the hydrogen stream.
The membrane malfunction was exacerbated by operating the electrolyser below its minimum power level, a condition frequently encountered due to the variable output of the solar panels.
Additional factors contributed to the incident including:
- Design flaws: The system design lacked an oxygen removal component or a static spark prevention mechanism in the hydrogen storage tank, likely due to cost-cutting measures.
- Ignored warnings: Despite detection signalling that the oxygen level had risen above 3%, production continued to validate the test.
- Management failures: There was a failure to adhere to the safety requirement of daily testing the hydrogen stream quality.3
- Lessons learnt
The Gangneung accident underscores several critical lessons for the safe handling and storage of hydrogen:
Understand potential failure mechanisms
It is crucial to understand the interrelation between the membrane gas permeability of the electrolyser and its potential defects under dynamic operating conditions, especially when using renewable power sources like solar. Such an understanding can help anticipate and mitigate risks associated with variable power inputs.
Know your safe operating limits and act when exceeded
Operating equipment outside specified conditions can lead to catastrophic failures. Implementing on-situ diagnostics system capable of triggering emergency stops when safety limits are exceeded is essential. The absence of an automatic gas storage isolation system exacerbates the risk during unsafe conditions.
Additionally, improved and standardised performance and safety tests are needed. These tests should define more realistic testing requirements and conditions, particularly for partial and low load cycles, to ensure safe operation and variable power inputs.
Find out how you can use consequence modelling tool to simulate this accident
Learn moreExplosion and fire during hydrogen transportation trailer filling in Santa Clara, California, June 2019
- Incident summary
Shortcomings during the filling of a multi-cylinder trailer with gaseous hydrogen at a gas storage and transportation facility in Santa Clara led to an explosion followed by a jet fire. Whilst no injuries were reported, the blasts were felt up to eight kilometres away.4
- Cause
During the filling of the tube trailer, a leak occurred. One of the drivers attempted an unauthorised repair of the leaking valve. The personnel did not follow the proper procedures and a miscommunication between the two drivers resulted in the reopening of the pneumatic valve, allowing hydrogen to flow into the disconnected manifold pipe.
Hydrogen accumulated in the confined space with inadequate venting, forming a flammable air-hydrogen mixture. This mixture ignited, resulting in an explosion. The explosion was followed by a jet fire, and additional hydrogen fires continued due to the activation of multiple pressure relief device (PRD) seals and damaged O-rings.
- Lessons learnt
Hazard awareness
Understand potential failures and enhance fire protection measures at trailer/tanker transfer stations. This includes implementing improved fire detection systems, fire suppression equipment, and emergency response protocols to mitigate the risk of fire and explosions during hydrogen handling.
Training and retraining of personnel
Train all personnel involved in hydrogen operations, including drivers, technicians, and other staff members. Training should cover proper handling procedures, emergency response protocols, and hazard awareness to ensure that personnel are equipped to identify and address potential safety risks effectively.
Design and process vulnerable to human error
Implement standardised filling procedures, conduct regular equipment inspections, and implement safety features such as flow-limiting devices to prevent inadvertent errors during hydrogen transfers. Additionally, there is a need for advancements in PRDs to better handle fire exposure and venting requirements.
Fire from a hydrogen pipeline, Binnenmaas, The Netherlands, 2007
- Incident summary
A long-undetected leak in the hydrogen pipeline led to a release of hydrogen gas. This gas cloud was ignited by nearby welding activities, causing a small fire on the soil covering multiple pipelines.6
- Cause
The hydrogen pipeline leakage resulted from a combination of tension factors. Over several years, the gradual settlement of the pipeline and surrounding earth caused bending at fixed points like building feed-throughs. This bending stressed a nearby CP coupling, eventually causing the leak. Unauthorised heavy traffic and the placement of heavy equipment on the soil covering the pipeline also contributed to the incident.
Moreover, inspection responsibilities were poorly coordinated. This lack of coordination resulted in a lack of overall safety accountability, exacerbating the risks associated with the pipeline operation.
- Lessons learnt
Pipeline technical durability
Establish stringent criteria for the quality, installation, and maintenance of CP couplings in pipelines to mitigate stress exposure over their operational lifespan.
Supervision practices
Reassess ground settlement measurement policies, emphasising rigorous surveillance to prevent activities atop pipelines from causing damage. Prioritise coordination and efficiency among supervisors and inspectors over increasing their numbers. Clarify supervision and inspection roles, ensuring clear task division and including external parties in supervisory roles during pipeline corridor construction.
The importance of safety assessments for facilities handling hydrogen
Safety assessments for facilities handling hydrogen are crucial for protecting personnel, communities, and the environment. These assessments proactively identify and mitigate potential hazards related to hydrogen handling, storage, transportation, and use. By incorporating lessons learnt from past incidents, facilities can leverage valuable insights into real-world challenges and vulnerabilities, enhancing safety protocols, and emergency response plans.
Safety assessments also play a vital role in regulatory compliance, demonstrating a facility’s commitment to safe and responsible operations. By continuously integrating lessons learnt, facilities can improve safety practices and foster a culture of continuous improvement, ensuring the safe and effective deployment of hydrogen technologies.
Although safety assessments can be conducted internally, engaging third-party experts provides a valuable opportunity to bridge gaps in in-house expertise. External specialists contribute fresh perspectives and specialised knowledge, thus enhancing the thoroughness and accuracy of the risk assessment process.
For facilities conducting in-house safety assessments, advanced tools like FLACS, EFFECTS, and RISKCURVES from Gexcon are available. These tools enable detailed safety assessments by simulating potential catastrophic hydrogen scenarios, enhancing time and resource efficiency and reliability, and supporting the development of preventive measures. By learning from past incidents and leveraging these tools, we can pave the way for a safer, more sustainable hydrogen future.
Conclusion
In summary, whilst hydrogen offers significant potential for a clean energy transition, it also presents inherent safety challenges that must be addressed. Past incidents highlight the importance of implementing robust safety protocols, providing comprehensive training for personnel, and addressing design vulnerabilities susceptible to human error.
Safety assessments, informed by lessons learnt from previous incidents, play a crucial role in identifying and mitigating risks associated with hydrogen handling, storage, and transportation.
By prioritising safety measures and leveraging technological advancements, we can enhance safety practices and ensure the responsible deployment of hydrogen technologies for a sustainable energy future.
Learn how to identify and manage hydrogen hazards for safe deployment, especially in public-facing applications.
Learn moreReferences
1. Kim, Y. (2019) Review: Hydrogen Tank Explosion in Gangneung, South Korea. Center Hydrogen Safety Conference. Available at: Link
2. The Korea Times (2019) Hydrogen tank explosion kills 2 in Gangneung. Available at: Link
3. European Hydrogen Incidents and Accidents database HIAD 2.1, European Commission, Joint Research Centre, Petten, the Netherlands. Available at: Link
4. Hydrogen Safety panel (2021) Report on the June 2019 Hydrogen Explosion and Fire Incident in Santa Clara, California. Available at: Link
5. ABC 7 News (2019) Hydrogen explosion shakes Santa Clara neighborhood. Available at: Link
6. ARIA (2007) Leakage of a hydrogen-pipeline due to an inadequate inspection philosophy. Available at: Link
Authors
Viktoria Bohacikova
Technical Product Specialist at Gexcon
Sonia Ruiz Pérez
Product Manager at Gexcon
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