Overview
UNIREC H₂ is ABB’s multi-pulse thyristor rectifier, purpose-built for industrial hydrogen production.
Delivering up to 25 kA at 1500 VDC, UNIREC H2 supplies stable, efficient DC power to all major electrolyzer types – including Alkaline, PEM, SOEC, and AEM.
Available in air- and water-cooled configurations, UNIREC H2 combines ABB’s proven thyristor technology with advanced digital control and protection.
Designed for both greenfield and retrofit hydrogen projects, it delivers scalable, reliable, and cost-effective DC power – tailored for OEMs, EPCs, and plant operators worldwide.
KEY BENEFITS of unirec h2
Easy to integrate
Designed as a modular, standardized rectifier system that reduces installation effort, shortens delivery schedules and simplifies integration into electrolyzer-based hydrogen plants.Proven ABB rectifier technology
Built on ABB’s long-established multi-pulse thyristor converter platform, used in thousands of rectifier installations worldwide and delivering stable, precise DC output for mission-critical industrial processes.Global ABB expertise & lifecycle services
Backed by ABB’s global manufacturing footprint and service network, ensuring expert commissioning, maintenance, spare parts availability and long lifecycle support.Compliance with demanding standards
Engineered to meet major international electrical, industrial and grid compatibility standards, including IEC 61000, IEC 62271, EN 50160 and IEEE 519, ensuring safe and compliant operation in all markets.Scalable for any hydrogen plant size
Modular building blocks available in air-cooled (up to ~4.5 kA) and water-cooled (up to ~6 kA) configurations, scalable to ~36 kA for large electrolyzer clusters - supporting projects from pilot units to multi-MW installations.High efficiency, grid stability and built-in protection
Up to 99.6% conversion efficiency, excellent thermal performance (water-cooled), multi-pulse transformer configurations for grid-friendly operation, and comprehensive protection (overcurrent, overvoltage, thermal, DC short circuit).FREQUENTLY ASKED QUESTIONS
UNIREC H₂ is a thyristor-based high-efficiency power rectifier designed to supply stable DC power to industrial electrolyzers for hydrogen production. It supports alkaline, PEM and other electrolyzer technologies.
Thanks to its modular architecture, UNIREC H₂ scales from pilot hydrogen units to multi-megawatt plants, with current blocks up to ~4.5 kA (air-cooled) and ~6 kA (water-cooled), expandable to ~36 kA.
Yes. Standardized modules, flexible cooling options and pre-engineered configurations simplify installation, reduce engineering time and support fast deployment for OEMs, EPCs and plant designers.
Yes. It complies with key industrial and grid standards including IEC 61000-6-1/-3, IEC 62271-1, EN 50160 and IEEE 519, ensuring safe and reliable operation globally.
Customers can choose air-cooled units for simpler installations or water-cooled units for higher power density and better thermal management. Water-cooled units deliver up to three times the power in the same footprint.
keep your system performing at its best for decades
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