[SMM Analysis] Seawater Hydrogen Production Enters "China Time": Desalination-Free Electrolysis Technology Establishes a New Paradigm

1. Technological Breakthrough: China Pioneers New Paradigm in Direct Seawater Electrolysis

Recently, the kickoff meeting for the Guangdong Provincial Key R&D Program project "Split-Module Seawater Electrolysis Without Desalination for Hydrogen Production Technology and System Equipment" under the "New-Type Energy Storage and New Energy" category was successfully held at Shenzhen University. The project will focus on developing core technologies and equipment for highly efficient, compatible, and stable direct seawater hydrogen production. It aims to create the world's first 110 Nm³/h seawater electrolysis system without desalination, establishing a development path from laboratory to factory and pioneering the marine green hydrogen sector.

The IEA's 2024 World Energy Outlook predicts global oil demand will peak by 2030, while hydrogen applications in shipping and aviation may accelerate oil demand reduction.

2. Global Technology Deployment and Project Progress by Major Countries

1. Europe:AEM Technology and Offshore Wind Scaling Demonstrations

The EU's SEA4VOLT project develops anion exchange membrane (AEM) electrolyzers targeting direct seawater electrolysis without pretreatment, using non-precious metal catalysts and fluorine-free membranes to reduce green hydrogen costs. Germany's NortH2 project plans to build a 10 GW offshore wind-to-hydrogen system by 2040, producing 1 million mt of green hydrogen annually, with its AquaPrimus subproject launching a 28 MW pilot in 2025. The Dutch PosHYdon project couples offshore wind with desalination for hydrogen production (13,000 mt/year), though relying on costly pretreatment.

2. US:Exploring Salt-Tolerant Materials and Scaling Applications

US research focuses on chlorine-resistant electrode materials and membrane technologies. A University of Houston team proposed in Nature Reviews enhancing catalyst stability through protective layers and heteroatom doping, while exploring hybrid electrolysis (e.g., organic oxidation replacing oxygen evolution) to reduce side reactions. Companies like Bloom Energy are testing solid oxide electrolyzer (SOEC) performance in high-salinity environments, though commercialization remains slow.

3. Japan:Hydrogen Strategy Driving Technology Integration

Japan's Hydrogen Society Promotion Act invests ¥15 trillion in hydrogen supply chains, collaborating with Siemens Energy on PEM electrolysis, though seawater projects still mainly use desalination pretreatment. Its JIDAI project aims to build a floating offshore hydrogen platform in Hokkaido by 2030, combining wind-based production with liquid hydrogen storage/transport, targeting costs of ¥20/Nm³ (~1.3 yuan/m³).

4. Australia and Singapore: International Collaboration on New-Type Hydrogen Production Technology

The "Solar Thermal-Plasma Seawater Splitting for Hydrogen Production" project, a collaboration between Australia and the National University of Singapore, received funding from the Australian government. It leverages the synergistic effects of photothermal processes to enhance hydrogen production efficiency, aiming to reduce reliance on precious metal catalysts. By integrating plasma resonators and nanomaterials, this technology holds promise for achieving low-cost hydrogen production in offshore areas.

III. Technical Pathways and Cost Comparison

Global seawater-based hydrogen production primarily follows two major technical routes:

1. Direct Seawater Electrolysis: Represented by the technology developed by China's Xie Heping team, this method requires no pretreatment and offers significant cost advantages. When offshore wind power electricity prices fall below $0.11/kWh, the hydrogen production cost can be reduced to $15.89/kg. By 2030, China's cost is projected to drop below $15/kg, reaching a competitive threshold with gray hydrogen.

2. Desalination Followed by Electrolysis: Though mature, this approach incurs higher costs. The Dutch PosHYdon project yields hydrogen at approximately $3.5/kg, while Germany's TractebelOverdick project, which relies on reverse osmosis desalination, reports costs around $4/kg.

IV. Challenges and Future Directions

1. Current Technical Challenges

Material Durability: Optimization is still needed for Cl⁻ corrosion and Ca²⁺/Mg²⁺ precipitation during long-term operation. Chinese teams have managed to control corrosion rates at 0.01 mm/year through bipolar plate coating technology.

Cost Optimization: Green electricity costs must drop below $0.2/kWh to enable large-scale commercialization. China is progressively approaching this target via PV+ESS integration and equipment localisation.

Standards and Safety: The International Organization for Standardization (ISO) is developing safety regulations for offshore hydrogen production platforms. China-led Technical Requirements for Direct Seawater Electrolysis Hydrogen Production Systems is expected to be released by 2026.

2. Future Development Trends

Application Expansion: Green hydrogen will integrate with chemical products like synthetic ammonia and methanol, forming an entire industry chain encompassing "production-storage-utilization."

International Collaboration: Cross-border projects will accelerate technology transfer and standard mutual recognition.

Seawater-based hydrogen production technology is transitioning from the laboratory to industrialization, with China's breakthroughs offering a "Chinese solution" for global energy transition. Sustained material innovation and policy support are poised to make seawater-derived hydrogen a mainstream green hydrogen supply technology post-2030, reshaping the global energy landscape.