Four Generations of Stuart Technology

High-Power Water Electrolysis: A Century of Proven Performance

The patented RuggedCell™ system leverages a century of Stuart family experience in water electrolysis. The system builds upon three previous generations of clean hydrogen production technology.

The high-power unipolar architecture underlying the RuggedCell™ has achieved over 1 billion cell-hours of reliable operation in approximately 1,000 hydrogen plants in 100 countries.

RuggedCell™ technology builds on this legacy with new advancements in high-power water electrolysis.

Initial Design
and Refinement

Initial design, deployment and broad commercialization of Stuart unipolar technology.

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Technology Expanded for Large Scale Applications

Technology advancement and scaling for industrial applications, with 100 MW modules.

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Shift to Low and Medium Powered Applications

Shift to small, packaged hydrogen production appliances for mobility applications.

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New Opportunity for Large Scale Hydrogen Production

Focus on large-scale modules, simplified manufacturing, and renewables for industry, energy, and fleet mobility.

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Generation 1: Alexander T. Stuart (1882-1950)

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  • Initial design and feasibility assessment of Stuart unipolar technology
  • Novel high ampere current approach utilized electrodes with a large surface area to improve energy efficiency


  • Technology advancement and demonstration at field installations
  • First patents granted


  • Ongoing technology refinement
  • Start of commercial sales under license

1948 Onwards:

  • Founding of The Electrolyser Corporation
  • Start of in-house electrolyzer manufacturing and direct sales to customers
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1927 Cells Patent

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A row of Stuart Technology electrolyzers.

Generation 2: Alexander K. "Sandy" Stuart (1924-2014)

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The Stuart unipolar technology platform was expanded for large-scale applications, with 100 MW modules.

  • Initially, the focus on large-scale plants was driven by a global search for fossil fuel alternatives in response to soaring oil prices and energy insecurity in the wake of the 1974 OPEC oil embargo.
  • This led to development of the EI-250 Cell System, which featured many of the core attributes of today’s RuggedCell™ water electrolyzers.
  • Advancements included a new, more efficient electrode design in place of steel sheets and the utilization of electrocatalysts to improve cell energy efficiency.
  • Major installations were provided to a Hydro-Québec–Air Liquide joint venture in Bécancour, Quebec (1987) and Peroxidos do Brasil Ltda. in Curitiba, Brazil (1988).
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Generation 3: Andrew T.B. Stuart (1962-Present)

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The technology focus shifted to compact mobile hydrogen production systems designed for low and medium-powered applications such as passenger vehicles.

  • The shift responded to market and regulatory demands to reduce air pollution.
  • 1991-1998: validated coupling of Stuart unipolar-type cells with solar power.
  • In the late 1990s, the Stuart Family’s Electrolyser Corporation was rebranded as Stuart Energy Systems Corp.
  • In 2003, Stuart Energy acquired a bipolar alkaline electrolyzer technology platform better suited to the small-scale applications it was targeting.
  • The company subsequently merged with another hydrogen technology company, Hydrogenics.
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Generation 4: Edward D.B. Stuart (1999-Present)

Headshot of Edward Stuart, VP of Development for Hydrogen Optimized.

Recognizing a new opportunity for large-scale water electrolysis in response to a global push to reduce carbon emissions, Andrew and Edward Stuart founded Hydrogen Optimized, Inc. in 2017.

  • Large-scale Stuart unipolar technology was identified as the best solution for hard-to-abate major industries.
  • The legacy technology was advanced to enable low-cost mass manufacturing and very high-power cell modules that can exceed 100 MW.
  • 2017: Initial trials and demonstration of the new-generation RuggedCell™ system.
  • 2021: Start of full-scale demonstration of the RuggedCell™ at the company’s newly opened Owen Sound facility.
  • 2022: successfully demonstrated coupling RuggedCell™ with intermittent renewable power
  • 2022: strategic partnership formed with ABB, which also invested in parent company Key DH Technologies Inc.
  • 2023: commercial market-ready 100 kA RuggedCell™ system proven; 100 MW/year manufacturing production completed.
  • With the ongoing implementation of factory automation, manufacturing capacity will reach 500 MW/year in 2024.
  • Output at the Owen Sound facility will be expanded to 2 GW/year as demand grows.


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