Introduction

As the world shifts toward renewable energy, green hydrogen—produced using electrolysis powered by clean electricity—has emerged as a key player in decarbonizing industries like transportation, steelmaking, and chemicals. Among the different electrolyzer technologies, alkaline electrolyzers (ALK) currently dominate the market. But why?

In this blog, we’ll explore the advantages of alkaline electrolyzers, their role in green hydrogen production, and why they remain the preferred choice for large-scale projects.

 

What Are Alkaline Electrolyzers?

Alkaline electrolyzers have been around for decades and are one of the most mature technologies for hydrogen production. They use an alkaline solution (typically potassium hydroxide, KOH) as an electrolyte and nickel-based electrodes to split water (H₂O) into hydrogen (H₂) and oxygen (O₂) through an electrochemical reaction.

Key Reaction:

At the cathode: 2H₂O + 2e⁻ → H₂ + 2OH⁻
At the anode: 2OH⁻ → ½O₂ + H₂O + 2e⁻

 

Why Alkaline Electrolyzers Dominate the Market

1. Proven Technology & Reliability

Alkaline electrolyzers have been used for industrial hydrogen production since the early 20th century. Their long track record makes them a low-risk choice for large-scale projects compared to newer technologies like PEM (Proton Exchange Membrane) or SOEC (Solid Oxide Electrolyzers).

2. Lower Capital Costs

One of the biggest advantages of ALK systems is their cost-effectiveness. They use non-precious metals (e.g., nickel instead of platinum or iridium), making them significantly cheaper than PEM electrolyzers, which rely on expensive catalysts.

3. Scalability for Industrial Use

Alkaline electrolyzers are ideal for large-scale hydrogen production, such as ammonia plants or refineries.

4. Longer Lifespan & Durability

With fewer degradation issues than PEM systems, ALKs often have lifespans about 20 years, reducing long-term operational costs. Their robust construction makes them suitable for harsh industrial environments.

5. Compatibility with Renewable Energy

While ALKs traditionally required stable power inputs, advancements in dynamic operation have improved their ability to work with intermittent renewable sources like wind and solar.

 

Challenges & Future Improvements

Despite their advantages, alkaline electrolyzers face some limitations:

Lower Efficiency at Partial Loads – They perform best at steady, high-capacity operation.

Slower Response Times – Less flexible than PEM electrolyzers for rapid start-stop cycles.

Liquid Electrolyte Maintenance – Requires periodic refilling and corrosion management.

 

However, innovations such as:
Advanced electrode materials (improving efficiency)
Zero-gap configurations (reducing energy losses)
Hybrid systems (ALK + PEM)
are helping ALKs stay competitive.

 

Conclusion: Alkaline Electrolyzers Lead the Green Hydrogen Race

While newer electrolyzer technologies are gaining attention, alkaline electrolyzers remain the market leader due to their cost efficiency, scalability, and proven reliability. As green hydrogen demand grows, ALKs will continue playing a crucial role in the energy transition—especially for large industrial applications.

For now, they are the go-to solution for cost-effective, large-scale green hydrogen production.

In the field of hydrogen production, choosing the right electrolyzer stack is crucial. Currently, the two most popular types of stacks are the Alkaline Electrolyzer stack and the PEM Electrolyzer stack. But which one is better suited to your needs? Let’s dive deeper to help you make an informed decision.

 

1. What is an Alkaline Electrolyzer Stack?

An ALK Electrolyzer stack uses an lye solution, typically potassium hydroxide (KOH), as the electrolyte. This technology has been around for decades and is known for its reliability and cost-effectiveness. Due to its lower operational costs and longer lifespan, alkaline electrolyzer stacks are well-suited for large-scale hydrogen production.

 

2. What is a PEM Electrolyzer Stack?

A PEM Electrolyzer Stack(Proton Exchange Membrane) uses a solid polymer electrolyte. This type of stack is more compact and can operate at higher current densities, making it suitable for applications where space is limited. PEM electrolyzer stacks can better adapt to variable power inputs, making them ideal for use in conjunction with renewable energy sources such as wind and solar.

 

3. Conclusion

The choice between alkaline electrolyzer stack or PEM electrolyzer stack depends on your specific needs for hydrogen production.

ALK electrolyzer stack: suitable for low-cost, large-scale, and low water quality requirements scenarios, such as industrial by-product hydrogen and power grid peak shaving.

PEM electrolyzer stack: suitable for scenarios with high purity, fast response, and limited space, such as hydrogen refueling stations and vehicle mounted hydrogen production.

By understanding the advantages and disadvantages of each electrolyzer stack, you can optimize the hydrogen production process and achieve sustainable development goals more efficiently.