(48b) Development of Safety Standards for Large-Scale Water Electrolysis Systems

As global interest in hydrogen energy increases, large-scale water electrolysis systems are gaining attention for their role in producing green hydrogen. In South Korea, a hydrogen explosion incident in 2019 during a demonstration of a renewable energy-coupled electrolysis system triggered the development of regulatory frameworks, including the enactment of the Hydrogen Economy Promotion and Hydrogen Safety Management Act in 2020. This act defined hydrogen-related equipment and facility as water electrolysis systems, hydrogen extraction systems, stationary fuel cells, mobile fuel cells.

Recently, water electrolysis systems have been required to develop various technologies for realizing a green hydrogen society, such as nominal & partial load performance, pressurized operations, operation flexibility, capacity scaling, lifetime, investment & maintenance cost. In South Korea, demonstration projects have validated single-stack electrolysis capacities of approximately 1 MW with efficiencies reaching 4.8–5.0 kWh/Nm³H2. In this way, as system sizes continue to increase, these systems will increasingly be resembled to facilities of the plant size.

Thus, we are considering the need to update safety standards tailored to their scale and complexity. KGS AH271, the national standard governing water electrolysis systems in South Korea, currently applies to various electrolysis technologies(alkaline, AEM, PEM) without capacity restrictions. However, its design is largely oriented toward smaller-scale systems like enclosure type electrolyzers, lacking detailed guidance for facility-wide integration and risk mitigation at larger scales. International standards—such as ISO 22734, ISO/TR 15916, and NFPA 2, NFPA 70—offer more comprehensive approaches for facility-level safety, incorporating aspects like zoning, ventilation, explosion control, proper material selection, hydrogen leak detection systems, and risk assessment protocols. As large-scale hydrogen facilities pose higher risks due to increased volumes, pressures, and potential for gas accumulation, these omissions could lead to underestimation of operational hazards.

To support the development of more safe regulations, we first compared and analyzed domestic & international safety standards of water electrolysis systems. And then reviewed safety consideration in these systems. In the future, we are considering to adopt a risk based approach that includes risk assessments(HAZOP, LOPA, QRA), hydrogen dispersion and explosion modeling using CFD tools such as FLACS. Finally we will update KGS AH271 by verifying the validity of safety standard frameworks through in-depth discussion with experts from domestic industry, academia, and research institutes.

The outcome of this work is expected to serve as a foundation for revising KGS AH271 or drafting a new standard entirely for large-scale hydrogen production systems. Such initiatives will align domestic standards with global best practices, enabling safer deployment of hydrogen infrastructure in Korea’s evolving energy landscape.