As the world shifts toward clean energy, green hydrogen—produced using renewable electricity—has emerged as a key player in decarbonizing industries like transportation, steel, and chemicals. However, a major barrier to widespread adoption is high production costs. Among the available electrolysis technologies, alkaline electrolyzers (ALK) present a promising path to cost reduction.

 

In this blog, we explore:

Why hydrogen production costs need to decrease

How alkaline electrolyzers work and their cost advantages

Recent advancements making ALK more competitive

The future outlook for affordable green hydrogen

 

The Challenge: High Costs of Green Hydrogen

Currently, most hydrogen is produced from fossil fuels (gray hydrogen), which is cheap but emits CO₂. Green hydrogen, made via water electrolysis powered by renewables, is clean but expensive due to:

High electricity costs (if not from surplus renewables)

Capital expenditures of electrolyzers

Maintenance and efficiency losses

For green hydrogen to compete, electrolyzer costs must drop significantly—and alkaline electrolyzers are leading the charge.

 

Why Alkaline Electrolyzers (ALK)?

Alkaline electrolyzers are one of the oldest and most mature electrolysis technologies. Compared to alternatives like PEM (Proton Exchange Membrane) and SOEC (Solid Oxide Electrolysis Cells), ALK offers:

1. Lower Capital Costs

No expensive materials: Unlike PEM electrolyzers, which require platinum and titanium, ALK uses nickel-based electrodes and liquid alkaline electrolytes (KOH or NaOH), reducing material costs.

Simpler construction: ALK operates at lower pressures and temperatures, avoiding costly high-performance components.

2. Longer Lifespan & Durability

Proven reliability: ALK systems often exceed 60,000–100,000 hours of operation with proper maintenance.

Less sensitivity to impurities: Unlike PEM, ALK tolerates varying water quality better, reducing pretreatment costs.

3. Scalability for Industrial Use

Large-scale hydrogen production: ALK systems are already used in ammonia plants and refineries, benefiting from economies of scale.

Compatibility with intermittent renewables: While PEM responds faster to variable power, newer ALK designs are improving flexibility.

Recent Innovations Driving Costs Down

 

While ALK has traditionally lagged behind PEM in efficiency, recent advancements are closing the gap:

1. Advanced Electrode Materials

Nanostructured nickel catalysts improve efficiency, reducing energy consumption.

Coating technologies enhance durability, lowering replacement costs.

2. Dynamic Operation for Renewable Integration

New ALK designs allow rapid load-following, making them better suited for wind and solar power fluctuations.

3. Manufacturing Scale-Up

Mass production of ALK stacks reduces per-unit costs.

4. Hybrid Systems (ALK + PEM)

Some projects combine ALK’s low cost with PEM’s responsiveness, optimizing performance.

 

The Future: Can ALK Make Green Hydrogen Affordable?

With continued R&D and scaling, alkaline electrolyzers could help reduce the cost of green hydrogen, making it competitive with fossil-based hydrogen. Key steps include:

✔ Further efficiency improvements (targeting <45 kWh/kg H₂)

✔ Automated manufacturing to cut production costs

✔ Integration with cheap renewable power (e.g., excess solar/wind)

 

While PEM electrolyzers often steal the spotlight for their high efficiency and flexibility, alkaline electrolyzers remain a cost-effective workhorse for large-scale green hydrogen production. With ongoing innovations, ALK could play a crucial role in making clean hydrogen affordable—accelerating the transition to a zero-emission energy future.

Alkaline electrolyzers have been a cornerstone of hydrogen production for decades, offering a reliable and cost-effective method for water electrolysis. However, their efficiency—defined as the ratio of energy input to hydrogen output—can vary significantly depending on several factors. Understanding these factors is crucial for optimizing performance, reducing costs, and improving the feasibility of green hydrogen production.

In this blog, we'll explore the key factors that influence the efficiency of alkaline electrolyzers and how they can be managed to enhance overall system performance.

 

1. Electrolyte Concentration and Composition

The alkaline solution (typically potassium hydroxide, KOH, or sodium hydroxide, NaOH) plays a critical role in ion conductivity and reaction kinetics.

Higher concentrations (20-30% KOH) improve ionic conductivity but can increase corrosion risks.

Lower concentrations reduce corrosion but may decrease efficiency due to higher ohmic losses.

Additives (e.g., inhibitors) can help mitigate degradation while maintaining performance.

 

2. Temperature Effects

Operating temperature significantly impacts reaction kinetics and overall efficiency:

Higher temperatures (70-90°C) reduce the thermodynamic voltage required for water splitting, improving efficiency.

Excessive heat (>90°C) may accelerate material degradation and increase gas crossover risks.

Optimal thermal management is essential to balance efficiency gains with system durability.

 

3. Current Density

The current density (A/cm²) directly affects hydrogen production rate and efficiency: 

Higher current densities increase hydrogen output but also raise ohmic losses and overpotentials.

Lower current densities improve efficiency but reduce production capacity.

Finding the optimal operating range is key to balancing efficiency and throughput.

 

4. Electrode Materials and Catalysts

The choice of electrodes influences overpotentials and longevity:

Nickel-based electrodes are common due to their stability and catalytic activity.

Advanced coatings (e.g., Ni-Mo, Ni-Fe, or Ni-S) can reduce overpotentials, improving efficiency.

Degradation over time (e.g., passivation, erosion) must be managed to sustain performance.

 

5. Separator/Membrane Performance

The diaphragm (traditionally asbestos, now often composite materials) must allow ion transport while minimizing gas crossover:

Thinner separators reduce ohmic resistance but may increase gas permeation.

Pore size optimization is critical to balance conductivity and gas purity.

Degradation (e.g., fouling, chemical attack) can reduce efficiency over time.

 

6. Pressure Conditions

Operating pressure affects gas evolution and system efficiency:

Higher pressures (>30 bar) reduce downstream compression needs but may increase gas crossover and energy losses.

Atmospheric pressure systems are simpler but require additional compression for storage.

 

7. System Design and Stack Configuration

Optimal electrode spacing reduces ohmic losses.

Flow field design ensures uniform electrolyte distribution and gas removal.

Bipolar vs. unipolar configurations impact voltage efficiency and scalability.

 

8. Power Supply and Load Variability

DC power quality (ripple, stability) affects electrolyzer performance.

Renewable energy integration (solar/wind) requires dynamic operation strategies to maintain efficiency under variable loads.

 

Conclusion

Improving alkaline electrolyzer efficiency requires a holistic approach, considering electrolyte properties, temperature, current density, materials, and system design. Ongoing research into advanced catalysts, durable separators, and optimized operating conditions continues to push the boundaries of efficiency, making alkaline electrolysis a competitive solution for large-scale green hydrogen production.

By addressing these key factors, operators and manufacturers can enhance performance, reduce energy consumption, and drive down the cost of hydrogen—bringing us closer to a sustainable energy future.

1. Technical Principles  

    Define Hydrogen Production Requirements: Determine the appropriate hydrogen production technology based on the scale and purity requirements of your facility. For example, water electrolysis may be more suitable for research institutions or the electronics industry that require high-purity hydrogen in relatively small quantities, as it can produce hydrogen with a purity of over 99.99%. For large-scale industrial hydrogen use, such as in oil refining or chemical industries, steam methane reforming (SMR) may be a more economical choice if abundant fossil fuel resources are available.  

2. Capacity and Scale  

    Assess Hydrogen Demand: Accurately evaluate future hydrogen usage based on production plans and process requirements. Large chemical enterprises may require hydrogen production equipment with a daily output of thousands or even tens of thousands of cubic meters, while small hydrogen refueling stations or laboratories may only need equipment with a daily output of a few hundred or even tens of cubic meters.  

Consider Space Constraints: The footprint and height of hydrogen production equipment are also important factors. Steam methane reforming equipment typically requires a larger site, including reactors and purification systems, while water electrolysis equipment is more compact and occupies less space. If the facility has limited space, compact hydrogen production equipment, such as skid-mounted water electrolysis systems, should be considered.  

3. Purity Requirements  

   Production Process Needs: Different industrial processes have varying hydrogen purity requirements. For instance, in semiconductor manufacturing, hydrogen purity must exceed 99.999% to avoid impurities affecting chip quality, while in some ordinary chemical hydrogenation reactions, a purity of around 98% may suffice.  

Supporting Purification Equipment: If the hydrogen produced by the equipment does not meet the required purity, additional purification systems must be considered. For example, pressure swing adsorption (PSA) systems can further enhance hydrogen purity by removing impurities such as carbon dioxide, carbon monoxide, and water vapor.  

4. Cost Factors  

   Equipment Procurement Costs: The prices of hydrogen production equipment vary significantly depending on the type and scale. Generally, water electrolysis equipment, especially those using proton exchange membrane (PEM) technology, has a higher initial investment, while steam methane reforming equipment is relatively cheaper, though the price also depends on capacity and technical parameters.  

Operation and Maintenance Costs: These include energy consumption, raw material costs, and maintenance expenses. Water electrolysis has high energy consumption, with electricity being the primary operating cost, while steam methane reforming requires significant fossil fuel consumption, making raw material costs a major factor. Additionally, advanced hydrogen production equipment may require specialized technicians for maintenance, increasing operational costs.  

Lifecycle Costs: Consider the equipment's lifespan, depreciation rate, and maintenance costs to calculate the total cost over its lifecycle. Equipment with higher upfront costs but stable performance, long service life, and low maintenance costs may offer better cost-effectiveness in the long run.  

5. Safety and Reliability  

   Safety Performance: Hydrogen production involves flammable and explosive gases, making safety critical. Choose equipment with comprehensive safety features, such as overpressure protection, overtemperature protection, and hydrogen leak detection and alarm systems. Additionally, the materials and manufacturing processes of the equipment must comply with relevant safety standards to ensure safe operation.  

Reliability and Stability: The reliability of the equipment directly impacts production continuity and stability. Select suppliers with a strong reputation, mature technology, and extensive application experience. Their products are typically better designed, manufactured, and quality-controlled, reducing the risk of equipment failure and downtime.  

6.Supplier's Technical Support 

   Additionally, consider the supplier's technical support and after-sales services, including equipment installation and commissioning, operator training, maintenance services, and spare parts supply. Timely and professional technical support ensures smooth equipment operation and minimizes losses caused by equipment failures.