CAN POINT-OF-USE HYDROGEN PRODUCTION BE TRULY SAFE AND SUSTAINABLE BY DESIGN? EAT’S Si+ PATHWAY OFFERS A VERSATILE AND SCALABLE SOLUTION FOR CROSS-SECTOR APPLICATIONS

Despite the well-documented progress in hydrogen (H₂) production and use cases, realizing the H₂ economy’s full potential across sectors demands a shift towards decentralized, safe, and sustainable methods. Current methods face challenges such as water scarcity, environmental bottlenecks in transportation, and safety concerns related to H2 storage and supply chains. Notable global initiatives and projects like the People’s Republic of China’s comprehensive strategy on integrating H2 into various sectors, India’s “National Green Hydrogen Mission”, the European Union’s “eGHOST” and “GUESS Why – GUidelinEs for Safe and Sustainable-by-design systems based on reneWable Hydrogen”, and the United States of America’s “Safety Planning for Hydrogen and Fuel Cell Projects” reflect this multifaceted view. Despite this growth and various governments’ uptake, we believe that further innovation in the production method itself is essential to achieve decentralized, safe, and sustainable H₂ production, as the inherent limitations of traditional approaches (which produce H₂ not for point of use) from a supply chain perspective will persist no matter what’s the source of H₂ is?
To address the limitations mentioned above, we present a novel technology capable of on-demand H₂ production at the point-of-use: the “Si+ pathway for H2 production, delivery, and storage”, developed through our project funded by Hong Kong Innovation and Technology Commission’s Partnership Research Programme in collaboration with EPRO Advance Technology (EAT) Ltd., and engineered for versatile cross-sector applications, including energy generation (electricity generation and fuel for transportation), industrial uses (heating and drying, fuel for electricity generation, and as a material supplier for construction curing and insulation), environmental remediation (especially as a water pollution removal), and water access. The European Commission’s Safe and Sustainable by Design (SSbD) framework is applied to validate the EAT’s Si+ pathway’s potential thereby addressing the research question by accounting for the technology readiness levels (TRLs) from ideation to pilot scale. As the pathway is still in the development stage for commercial use, we limited the SSbD framework to (re)-design phase. Using the European Chemicals Agency (ECHA) database and regulations such as CLP – Classification, Labelling and Packaging (EC No. 1272/2008), FCM – Food Contact Materials (EC No. 1935/2004), and REACH – Registration, Evaluation, Authorization and Restriction of Chemicals (EC No. 1907/2006), we then analyzed the pathway for its design, production, use, and end-of-life to ensure alignment with the eight (re)-design principles; 1. Material efficiency, 2. Minimizing hazardous materials, 3. Energy efficiency, 4. Renewable sources, 5. Preventing hazardous emissions, 6. Reducing exposure, 7. Designing for end-of-life (EoL), and 8. Considering the whole life cycle.
Results indicate that, considering the whole life cycle, the Si+ pathway demonstrates high material efficiency. More than 90% of the Si+ is consumed, and after accounting for a 16% loss, the remainder is recovered as non-toxic sodium silicates, a valuable by-product for industrial applications such as concrete curing. Material efficiency in terms of reactants and products is further enhanced through system expansion, utilizing a single non-toxic resource under circularization principles. This compensates for at least 80% of the resources required for H₂ production, leaving calcium silicates as by-products suitable for insulation applications. This pathway effectively addresses a central challenge in the H₂ economy by providing a solution for storage and transportation issues. It utilizes a non-toxic solid form of Si+, avoiding hazardous chemicals and materials in the whole supply chain. Additionally, this pathway exhibits a unique capability to generate substantial amounts of H2 on-demand, up to 14 wt.% at moderate temperatures, with heat recovery capabilities suitable even for nanoscale combined heat and power cycles, thus supporting energy efficiency. Furthermore, integration of on-board solar photovoltaics is observed to be feasible due to the modular design, promoting the use of renewable sources. The design’s modularity and compactness facilitate easier decommissioning of reactors, based on our TRLs journey from designing 16 L/day, 150 L/day, and >100 kg/day reactors. All materials, especially stainless steel and other materials, can be recovered, making it an EoL-friendly design. Life cycle assessment of H2 production via this pathway in the European Union, considering the transport of solid Si+(recycled) and other resources from China, reveals a potential for emitting 1.09 – 1.49 kgCO₂e/kg H₂ produced. This assessment does not include the offsetting benefits inherent in the pathway. The Si+ pathway, through its inherent design, not only offered modularity and plug-and-play energy generation capabilities but also ensured adherence to safety and sustainability principles by design, making it an ideal solution for point-of-use H2 production.