- Onboard Integration Achieves a Compact and Lightweight Design and Is Expected to More Than Double Operating Range -

DANGJIN, South Korea – June 10 – The Korea Railroad Research Institute (KRRI) (President: Sagong Myung) has successfully developed a liquid hydrogen supply system for railway mobility and held a demonstration of a hybrid propulsion system utilizing liquid hydrogen as a propulsion energy source on June 9 at a test site in Dangjin, Chungcheongnam-do. The event was attended by approximately 30 representatives from the railway industry, including Hyundai Rotem, as well as related organizations.

KRRI has been developing key technologies for liquid hydrogen-based hydrogen-electric locomotives, including fuel cell parallel control technology, power control-based (DC-DC hybrid) propulsion technology, and an onboard integrated liquid hydrogen storage and supply system.

The newly developed Onboard Integrated Liquid Hydrogen Storage and Supply System (hereinafter referred to as the “System“) maximizes thermal insulation and vaporization performance while achieving a compact and lightweight design suitable for onboard installation through integrated system architecture.

The System consists of a highly insulated storage vessel* designed for the safe, long-term storage of cryogenic liquid hydrogen and a vaporization system** that provides a stable supply of gaseous hydrogen to fuel cells through efficient vaporization and pressure control.

The storage vessel incorporates a thermal insulation structure utilizing Kevlar, a high-performance synthetic fiber that offers exceptional strength while remaining lightweight and maintaining stability at elevated temperatures.
By applying a high-efficiency plate heat exchanger and in-tank self-pressurization PBU (Pressure Build-Up) technology, the system achieves approximately a 75% reduction in volume compared with conventional tubular heat exchangers, resulting in a more compact and lightweight vaporization system.

The liquid hydrogen supply technology rapidly converts cryogenic liquid hydrogen at –253°C into gaseous hydrogen at ambient temperature and regulates the supply pressure within a range of 12–17 bar before supplying it to fuel cells. The technology was developed for application in propulsion systems for high-power mobility platforms such as railways and ships.

The System is the world’s first platform capable of parallel control of four 100 kW-class fuel cells. It also incorporates two 300 kW voltage stabilization devices (DC-DC converters), two 150 kWh battery packs, an onboard integrated liquid hydrogen supply system, and a 600 kW load bank. Various performance tests, including load fluctuation tests and fault response tests, will be conducted in the future.

Currently, detailed regulations governing the utilization of liquid hydrogen have not yet been established in Korea, making demonstration projects under a regulatory sandbox framework necessary.

KRRI began preparation for a regulatory sandbox in December 2021 and obtained government approval in July 2023. Subsequently, the Phase 2 Safety Management Plan was approved by the Ministry of Trade, Industry and Energy and the Korea Gas Safety Corporation.

Accordingly, KRRI plans to conduct additional integrated system tests covering the liquid hydrogen storage tank, DC-DC converter, and load equipment to verify the performance of core liquid hydrogen mobility technologies in accordance with approved testing procedures and safety management plans.

This research was conducted as part of KRRI’s basic research program under the National Research Council of Science and Technology (NST) (Chairman: Kim Young-sik) through the project entitled “Development of Compact and Lightweight Onboard Liquid Hydrogen Supply System Technology.”

The System can be applied to railway vehicles and is expected not only to support hydrogen trams but also to accelerate the conversion of aging diesel trains to liquid hydrogen propulsion systems. In addition, it is expected to more than double the maximum operating range of existing hydrogen trains from approximately 600 km on a single refueling.

※ Relevant Research Project
- Project Title: Development of Compact and Lightweight Onboard Liquid Hydrogen Supply System Technology (Research period: January 1, 2025 ~ December 31, 2026)
- Principal Investigator: Kim Gil-dong, Principal Researcher, KRRI

Kim Gil-dong, Principal Researcher at KRRI and principal investigator of the project, stated, “Compared with conventional gaseous hydrogen, liquid hydrogen technology offers groundbreaking improvements in storage and transportation. It also provides significant advantages for railway applications, including rapid refueling and long-distance operation,” adding, “Alongside improvements to the regulatory framework, we plan to first apply this technology to hydrogen electric trams to verify operational efficiency and continue expanding our commercialization efforts.”

Sagong Myung, President of KRRI said, “We expect this system to significantly expand the application of liquid hydrogen in mobility sectors requiring large fuel capacities, such as railways and maritime transportation,” adding, “We will continue to strengthen the development of various K-Hydrogen Railway technologies to support carbon neutrality and address climate change.”

※ Reference: Photos from the Onboard Liquid Hydrogen Storage and Supply System Achievement Presentation Event





Press Contacts
Sunghyun Baek
Korea Railroad Research Institute
baeksh@krri.re.kr
+82 31 460 5162