
Technology

Hydrogen Optimized’s patented RuggedCellTM unipolar alkaline water electrolyzer build on the proven Stuart technology platform with new innovations in high-power electrolysis. Designed for large-scale applications, the RuggedCell™‘s 4th-generation Stuart technology delivers the key attributes PEM and bipolar alkaline electrolyzer systems.
- Delivers the benefits of PEM electrolysis technology
- Solves the key issues associated with PEM and bipolar alkaline and PEM technologies
PEM vs. Bipolar Alkaline vs. Stuart Unipolar Alkaline Water Electrolysis:
A Comparison of Key Attributes
Key Attributes | PEM | Bipolar Alkaline | Stuart Unipolar Alkaline |
---|---|---|---|
Compact footprint at scale | |||
Load following with renewable power | |||
No electrocycle circulation pumps | |||
Low capital cost | |||
Extensive commercial track record | some | ||
Electrolysis cell lifetime > 20 years | some | ||
PFAS “forever chemical”-free | |||
Iridium-free | |||
50 MW+ module | |||
Excellent gas purity over full dynamic range | |||
≈ 100% Faradaic Efficiency over dynamic range | |||
Stable efficiency over plant life | |||
Low-cost on-site maintenance |
Technology Characteristics At Large Scale
Technology Characteristics | PEM | Bipolar Alkaline | Stuart Unipolar Alkaline |
---|---|---|---|
Compact footprint at scale | Very High | High | Low |
Load following with renewable power | Low | Medium | High |
No electrocycle circulation pumps | High | Medium | Low |
Low capital cost | Short | Short/Medium | Long |
Extensive commercial track record | High | Medium | Low |
Electrolysis cell lifetime > 20 years | High | Medium/Low | Low |
Built for Large-Scale
The RuggedCell™’s unipolar design enables very high-power single modules for the world’s largest clean hydrogen facilities.
- RuggedCell™ assembly begins with repetitive individual Current Carrier Frame elements
- The elements are stacked in parallel to create very high ampere single cells, enabled by Hydrogen Optimized’s patented Current Carrier Frame.
- Multiple single cell units are then combined into very high-power single water electrolysis modules.
- Grouped together, the modules are the foundation of the world’s largest clean hydrogen plants.

Proven Stuart Water Electrolysis Technology: Built to Perform for Plant Life
The RuggedCell™’s unipolar design enables very high-power single modules for the world’s largest clean hydrogen facilities.
- 1 billion cell hours of proven Stuart technology experience
- Backed by 100 years of Stuart legacy in unipolar water electrolysis
- ~1,000 hydrogen plants in 100 countries

Stuart technology is built into every RuggedCell™
- Identical electrochemical environment
- Commonly available materials
- Proven durability over decades in alkaline environments
- Maintains stable energy efficiency without the use of Iridium
- Proven plant design
- Peripheral equipment has an outstanding track record
The RuggedCellTM’s 4th-generation Stuart technology is optimized for:
- Mass Manufacturing
- On-site maintenance
- Operational flexibility with renewables
The RuggedCell™’s Stuart Technology Legacy
Alexander T. Stuart commercialized the 1st generation of his unipolar water electrolysis technology in 1913. His novel approach utilized electrodes with a very high surface area to improve energy efficiency, with a high (24,000+) ampere current.

2nd generation Stuart technology, developed by Alexander K. Stuart and his team, advanced the electrode design to drive down resistance factors and further improve the energy efficiency of the cells, which could be configured into 100 MW modules.
3rd generation Stuart technology, developed by Andrew T. B. Stuart and his team, employed a monopolar approach that enabled low resistance factor unipolar cells in a more compact design for low and medium power applications.
From this more than century-old technology foundation, Andrew Stuart led a team that included his son Edward and daughter Samantha in the development the RuggedCell™, the 4th generation of Stuart technology. Their efforts enabled the mass manufacturing of very high power unipolar alkaline cell modules that could exceed 100 MW and be produced at exceptionally low cost.
A Stronger Technology Offering in Collaboration with ABB
Our company’s strategic relationship with ABB, a global leader in power and automation technologies, has made it possible for us to create a robust end-to-end solution for the world’s largest green hydrogen facilities. RuggedCell™ clean hydrogen plants
incorporate:
- ABB high-power rectifiers with RuggedCell™ high-power electrolyzers
- ABB distributed control systems, enabling 24/7 global operator and technical support
- ABB leadership in electrical engineering for renewable power connections to RuggedCell™ electrolyzers as well as grid stabilization
Continuous Customer Support:
Hydrogen Optimized Global Interactive Customer Care Centre
The RuggedCell™ is designed for easy, low-cost on-site maintenance:
- Each individual RuggedCell™ is instrumented for real-time performance monitoring
- Maximizes plant up-time
Should issues arise, we have created the Hydrogen Optimized Global Interactive Customer Care Centre. This facility provides the infrastructure and personnel to keep each client’s RuggedCell™ hydrogen plant operating continuously at optimum performance.
Should issues arise, we have created the Hydrogen Optimized Global Interactive Customer Care Centre. This facility provides the infrastructure and personnel to keep each client’s RuggedCell™ hydrogen plant operating continuously at optimum performance.
We offer service packages that provide:
- 4/7 interactive customer support, including directly to the plant operator
- Service technicians for both remote and on-site visits
- Plant data analysis to support optimal system performance
- Customized predictive maintenance schedule
- Plant maintenance support – on-site if required