KeyPoints for improving Green Hydrogen

Green hydrogen, the only near-zero emission form, requires so much energy to produce that its resulting energy inefficiency is its greatest weakness.

The problem with hydrogen electrolysis is financial feasibility, as the process has typically been expensive and highly inefficient. Producing hydrogen at the scale required to replace fossil fuels is a proposal that never excited investors, as water electrolysis efficiency rate is roughly 75%. This means that for every 1 kg of hydrogen, which has a specific energy of 143 MJ/kg (39.7 kWh), electrolysis requires about 200 MJ of electricity (55 kWh).

This form of hydrogen is made using electrolysers, which split water into hydrogen and oxygen in the process of electrolysis, powered by renewable electricity generated from wind or solar energy.We’ll need lots of electrolysers, running on renewable or nuclear electricity, to replace the tens of millions of tonnes of hydrogen currently made from fossil fuels without carbon capture. This hydrogen is used to make chemicals and fertilisers – all uses which will be needed post-decarbonisation. We’ll need lots of electrolysers, running on renewable or nuclear electricity, to replace the tens of millions of tonnes of hydrogen currently made from fossil fuels without carbon capture.

the only solution for Green Hydrogen and energy transition is developing next-generation electrolysers with more than 95% efficiency .While these electrolysers may have the potential to marginally improve the energy efficiency of electrolysis, they unfortunately do not address the fundamental problem of the process – it destroys exergy.

Exergy is, most simply, a measure of the potential of a unit of energy to do work.

For Developing next-generation electrolysers it shall consider the following

1. Improved Electrode Materials:

Choosing materials with high catalytic activity and stability can reduce overpotential, the extra energy needed to drive the electrolysis reaction.

- Platinum (Pt): A precious metal widely used as a catalyst due to its high catalytic activity and stability in electrochemical reactions.

- Iridium (Ir): Another precious metal with excellent corrosion resistance and catalytic properties, often used as an electrode material in harsh environments.

- Ruthenium (Ru): Known for its catalytic activity, ruthenium is used in various electrochemical applications, including electrolysis.

- Transition Metal Oxides: These materials, such as nickel oxide (NiO), cobalt oxide (Co3O4), or manganese oxide (MnO2), exhibit catalytic activity and can serve as alternatives to precious metals for electrode applications.

- Carbon-Based Materials: Carbon-based materials like carbon nanotubes, graphene, or carbon black can also function as catalyst supports or electrode materials, offering high surface area and conductivity.

2. Enhanced Electrolyte Conductivity:

Using electrolytes with higher conductivity facilitates faster ion transport within the cell, reducing internal resistance and improving efficiency

- Potassium Hydroxide (KOH): An alkaline electrolyte commonly used in alkaline electrolysis due to its high conductivity and compatibility with electrode materials.

- Sodium Hydroxide (NaOH): Another alkaline electrolyte similar to KOH, often used in electrolysis applications.

- Ionic Conductivity: Refers to the ability of an electrolyte to conduct ions. Higher ionic conductivity allows for faster ion transport within the electrolyte solution, reducing internal resistance in the electrolyzer cell.

3. Optimized Cell Design:

Designing electrolyzer cells with minimal distance between electrodes and efficient flow paths for electrolyte can reduce resistance and enhance mass transfer.

- Flow Channels: Channels or pathways designed within the cell structure to facilitate uniform distribution of electrolyte flow and minimize concentration gradients.

- Porous Electrodes: Electrodes with a porous structure to enhance surface area and facilitate gas and liquid transport, improving mass transfer efficiency.

- Membrane Separators: Thin membranes placed between electrodes to prevent mixing of reactants and products while allowing ion transport, essential for separating gases produced during electrolysis.

4. Increased Operating Temperature:

Operating at higher temperatures can lower the activation energy for electrolysis reactions, improving efficiency. However, this must be balanced with considerations for material stability and safety.

- Solid Oxide Electrolysis Cells (SOECs): High-temperature electrolysis cells that operate at temperatures typically above 500°C, utilizing solid oxide electrolytes like yttria-stabilized zirconia (YSZ) or ceria (CeO2) for ion transport.

- Thermal Management: Techniques and systems employed to control and regulate temperature within the electrolyzer cell, ensuring optimal operating conditions while preventing overheating or thermal degradation of materials.

5. Utilization of Renewable Energy:

Powering electrolyzers with renewable energy sources such as solar or wind can reduce overall carbon footprint and make the process more sustainable.

- Solar Power: Energy derived from sunlight, often harnessed through photovoltaic (PV) panels to generate electricity for electrolysis.

-Wind Power: Energy generated from wind turbines, utilized to power electrolyzers directly or to produce hydrogen during periods of excess wind energy production.

- Hydropower: Energy derived from the gravitational force of flowing or falling water, commonly used to generate electricity for electrolysis in regions with suitable water resources.

6. Advanced Control Algorithms

Implementing sophisticated control algorithms can optimize operating parameters such as current density, temperature, and flow rates to maximize efficiency under varying conditions.

Model-Based Predictive Control: Control strategy that utilizes mathematical models of the electrolyzer system to predict future behavior and optimize control actions accordingly.Adaptive Control Control method that continuously adjusts control parameters based on real-time feedback from the electrolyzer system, adapting to changing operating conditions and optimizing performance.

7. Catalyst Utilization

Incorporating catalysts at electrode surfaces can accelerate the reaction kinetics, reducing energy losses and improving overall efficiency of electrolysis.

Metal Oxides: Transition metal oxides such as nickel oxide (NiO), cobalt oxide (Co3O4), or iron oxide (Fe2O3) can serve as catalysts or catalyst supports, offering high activity and stability.