To increase efficiency in green hydrogen production using alkaline electrolysis, several steps can be incorporated:

 To increase efficiency in green hydrogen production using alkaline electrolysis, several steps can be incorporated:

improving cell and stack design, optimizing operational parameters, and integrating advanced monitoring and control systems. This includes developing new cell components, optimizing gas flow, and using advanced control systems to manage temperature, pressure, and electrolyte flow rate. 

Here's a more detailed breakdown:

1. Cell and Stack Design Optimization:

Develop new cell/stack components:

Focus on improving materials and designs to enhance performance, especially at high current densities. 

High bubble removal rate:

Design cells with efficient bubble removal to minimize resistance and improve efficiency. 

Optimize electrode and diaphragm materials:

Explore new materials with enhanced conductivity, durability, and resistance to corrosion. 

Minimize gas crossover:

Improve the diaphragm to prevent hydrogen and oxygen from crossing over, reducing losses and ensuring hydrogen purity. 

2. Operational Parameter Optimization:

Temperature and pressure control:

Implement advanced control systems to maintain optimal operating conditions and prevent overheating or cavitation. 

Gas flow optimization:

Optimize gas flow rates to ensure efficient separation of hydrogen and oxygen and minimize losses. 

Electrolyte concentration and conductivity:

Monitor and control electrolyte concentration and conductivity to maintain optimal performance. 

Current density optimization:

Explore operating conditions at higher current densities while maintaining efficiency and longevity. 

System optimization:

Consider the trade-offs in system design, such as lye cooling sizing, to achieve the best overall efficiency and hydrogen costs. 

3. Integration of Advanced Monitoring and Control Systems:

Predictive maintenance:

Implement advanced process instrumentation and data analysis to enable predictive maintenance and minimize downtime. 

Remote monitoring and control:

Equip electrolyzers with advanced monitoring and control systems for remote monitoring, real-time adjustments, and predictive maintenance. 

Dynamic operating range:

Ensure that electrolyzers can handle fluctuations in power generation from renewable sources, such as solar or wind, by optimizing their dynamic operating range. 

Adaptive control strategies:

Develop adaptive control strategies that can adjust to changing operating conditions and maximize efficiency. 

4. Downstream Integration and Optimization:

High-pressure operation:

Consider integrating AWE with high-pressure operation to reduce compression energy consumption and improve overall efficiency. 

Integration with other technologies:

Explore integration with other technologies, such as gasification combined cycle systems, to improve overall system efficiency. 

By incorporating these steps, the efficiency of green hydrogen production using alkaline electrolysis can be significantly improved, making it a more competitive and sustainable technology.

The Four Main Types of Water Electrolysis Technology

Electrolysis cell during assembly

Which water electrolysis technologies are available on the market? What do they have in common? How do they differ? Our overview will shed some light on the subject.

In water electrolysis, water molecules are split into their basic components, hydrogen and oxygen, using electricity. If the electricity comes from renewable sources (e.g., wind or solar), green hydrogen is produced (keyword Power-to-X). So far so good. And yet, there are several technologies which can be used to produce (green) hydrogen production. We present an overview of the four main types of water electrolysis technologies and highlight their similarities and differences:

Alkaline Water Electrolysis (AWE)

Proton Exchange Membrane Electrolysis (PEM)

Solid Oxide Electrolysis (SOEC)

Anion Exchange Membrane Electrolysis (AEM)

Similarities of the four main water electrolysis technologies

Four technologies – a lot of similarities: all of the above-mentioned technologies have their design principle in common. As we saw in the explanations above, the cells of all technologies include an anode and a cathode, as well as a diaphragm, membrane, or electrolyte. The cells are surrounded by a bipolar plate and a current distributor. A cell is included into a zero-gap electrolysis stack, meaning that multiple cells are connected in series. Multiple stacks form an electrolysis stack module, varying from single digit megawatt to double digit megawatt, like thyssenkrupp nucera’s® 20MW scalum® unit. Similarities are clear now. But where do the four technologies differ? Let’s deep dive into the modes of operation to get a better understanding.

1. Alkaline Water Electrolysis (AWE)

Electrolysis Process

Simplified Alkaline Water Electrolysis process

Structure of AWE:

For Alkaline Water Electrolysis, electrodes are immersed in an alkaline solution, usually potassium hydroxide (KOH), which supports the transport of ions, and, thus, the electrolysis process. The electrodes are suspended in half cells that are separated by a permeable, ion-conducting membrane. This membrane is impermeable to gas and thus prevents oxygen and hydrogen from mixing.

AWE process:

At the cathode, electrons react with water, producing hydrogen (H2) and hydroxide ions (OH–).

2H2O + 2e– → H2 + 2OH–

The hydroxide ions can pass the diaphragm, while the hydrogen gas exits the cell. Hydroxide ions react at the anode and form oxygen (O2) and water (H2O), releasing electrons

2OH → ½O2 + H2O + 2e

Characteristics of AWE:

AWE works at high temperatures and high pressure.

It is characterized by high long-term stability and comparatively low investment costs.

Currently, AWE systems achieve the highest levels of efficiency.

AWE is ready for industrial-scale usage.