Rugged Cell

Designed for the Lowest Levelized Cost of Clean Hydrogen at Large Scale

Hydrogen Optimized’s patented RuggedCell™ unipolar alkaline water electrolyzers build on the proven Stuart technology platform with new innovations in high-power electrolysis. Designed for large-scale applications, RuggedCell™ technology:

  • Delivers the key benefits of PEM and bipolar alkaline electrolyzer systems
  • Solves the key issues associated with these technologies

The RuggedCell

  • Dynamic power response – from 0 to 100% in seconds
  • 20 year lifespan with minimal efficiency loss
  • Low-cost on-site maintenance
  • Free of Iridium and PFAS “forever chemicals”

EPCs, EPCMs and large clean hydrogen project developers:
for more detailed information on RuggedCell™ technology, click here.


RuggedCell™ Unipolar Architecture

The RuggedCell™ is unique among water electrolyzer systems for its unipolar architecture – a design historically associated with Stuart type cells. This enables many of the technology’s inherent advantages and makes it possible to build very high-power single modules for the world’s largest clean hydrogen facilities. Four main steps are involved in producing RuggedCell™ systems:

  1. RuggedCell™ assembly begins with repetitive individual Current Carrier Frame elements
  2. The elements are stacked in parallel to create very high ampere single cells, enabled by Hydrogen Optimized’s patented Current Carrier Frame
  3. Multiple single cell units are then combined into very high-power single water electrolysis modules
  4. Grouped together, the modules are the foundation of the world’s largest clean hydrogen plants


The RuggedCell™ system’s unipolar alkaline technology provides a wide array of attributes that make it ideal for large-scale clean hydrogen installations.

These attributes include low current density, operation at high amperes, low cost of materials, long asset lifespan, relatively low spare parts cost, and a low capital investment.


Computer-generated render of Hydrogen Optimized's RuggedCell.


The RuggedCell™’s unipolar design enables very high-power single modules for the world’s largest clean hydrogen facilities. These plants provide carbon-free energy for major industries such as chemical plants, utilities and heavy transportation. The system’s “at scale” design makes it possible to have fewer large modules instead of multiple smaller modules, thereby decreasing system complexity, and streamlining design, construction, installation and maintenance. This in turn facilitates the deployment of very large installations in “real world” renewable energy conditions, including at remote locations.

Historically, there was no need to consider electrolysis equipment for installations in the hundreds of megawatts. The RuggedCell™ was designed from the start to meet this need with a unique unipolar architecture.

Dollar sign in a black circle with a green arrow pointing downward indicating low cost.

Designed for the Lowest Levelized Cost of Clean Hydrogen at Large Scale

The RuggedCell™’s configurable system architecture enables cost-effective clean hydrogen plants ranging from tens of megawatts to gigawatt scale. Fewer large modules means minimal replication of substations, rectifiers, balance of stack, and balance of plant. PEM and bipolar alkaline systems, in contrast, require each of these components to be replicated numerous times for large installations.

Scale also drives up plant operating efficiencies. With no requirement for electrolyte circulation pumps, the RuggedCell™’s electrolytic cell performance delivers a high hydrogen yield for every kW of electrical power.

Two gauges with arrows pointing at zero and 100, representing dynamic range.

Dynamic Power Response

The patented RuggedCell™ system efficiently converts renewable electricity such as solar and wind power into clean hydrogen. Operating over the full dynamic range of available power, and capable of responding to wide variations in loads in seconds, the RuggedCell™ is well-suited to renewable power inputs. This capability makes it possible to avoid shutdowns at low renewable energy intensity while maximizing the conversion of electrical power to hydrogen. High gas purities are sustained over the full operating range, further driving down the levelized cost of hydrogen.

A Hydrogen Optimized employee inspecting the RuggedCell.

20 Year Lifespan

The RuggedCell™ is designed to minimize the root causes of performance degradation over time. The system delivers relatively stable efficiency over a long lifespan thanks to a proprietary electrode catalyst that is operated at a fraction of its capacity. Low system strain, and a unique unipolar electrochemical environment, provides mechanical and chemical stability over long timeframes.

Man wearing a yellow high-res jacket in a factory surrounded by stainless steel appliances.

Low-Cost Onsite Maintenance

The RuggedCell™ is designed for long-term reliability. In the event that maintenance is required, the system architecture allows for easy, on-site repair work. There is no need to ship electrolyzer cell assemblies to the factory; the RuggedCell™’s modular construction enables individual cells to be swapped out quickly and efficiently.

Furthermore, each individual cell is instrumented for real-time performance monitoring. That means issues can be quickly identified for rapid maintenance. Together, these features provide for cost savings and maximized plant up-time.

A quadrant photo:

No Iridium or PFAS Forever Chemicals

The RuggedCell™ design requires no platinum, iridium or other platinum group metals. This avoids the well-known supply chain and cost impediments associated with these materials. Instead, the cells are constructed with readily available materials – principally steel, copper and nickel. This enables cradle-to-cradle recycling of all parts, another key factor to achieve the lowest levelized cost of hydrogen.

Furthermore, no perfluorinated compounds (PFCs) are used. As a result, the RuggedCell™ system contains no toxic PFAS “forever chemicals”, which face regulatory scrutiny in some jurisdictions.


Hydrogen Optimized's RuggedCell water electrolysis system.

Proven Stuart Electrolysis Technology

The RuggedCell™’s design builds upon a foundation of proven Stuart unipolar technology. With a 100-year legacy and 1 billion cell-hours of operation, this technology has operated successfully in about 1,000 hydrogen plants in 100 countries.

Optimized for mass manufacturing, on-site maintenance and operational flexibility with renewables, the RuggedCell™ operates with an electrochemical environment identical to the Stuart cell.

Three blueprints rolled up on top of another spread-out blueprint.

EPCs Seeking Additional Information

EPCs, EPCMs and large clean hydrogen project developers:

For more detailed information on RuggedCell™ technology, click here.