Solid oxide fuel cells are basically the same as solid oxide electrolysers!

SOFC based machines have the advantage of being both fuel cells and electrolysers.

During times of extra renewable energy they can create hydrogen. During dunkelflaute they can then be reverse cycled to put energy back into the grid. 

This is a huge advantage over other types of pure electrolyzers.

The system using these of course is more complex, so let’s take a look at the technology:

How They Work:

Electrolyte: Uses a solid ceramic material to conduct oxygen ions.

Temperature: Operates at high temperatures (700-1000°C).

Reaction: Electricity splits water molecules into hydrogen and oxygen ions.

The oxygen ions move through the solid ceramic to form oxygen gas.

Pros:

• Very high efficiency
• Can use both electricity and heat, making it ideal for integrating with industrial processes.

Cons:

• High operating temperatures require special materials and can be challenging to manage.
• Expensive and complex technology.

Due to these high pressure and temperatures NOT all heat exchangers can handle this.

If you are planning to build an electrolysis machine using this technology, you should look into THERMOGYM advanced stainless steel and other materials.

Why do they heat up?

Fuel cell mode is exothermic, thus you get 1 watt of heat (roughly) for each watt of electricity that you get out.  So you “waste” the energy of the hydrogen into heat.

For electrolyser mode it is endothermic, thus you put in watts of electricity and get hydrogen and heat, this is pretty much the same, for ever watt of electricity you get 1 watts worth of chemical energy in the hydrogen and one watt in heat.

Thus round trip efficiency, is between 20-25%.  This process is ONLY useful (effective) in situations where you have EXTRA electricity that you don’t know what to do with on sunny and windy days, and you have a need during days/nights with no solar power.

All of the information:

Solid Oxide Electrolysers and fuel cells

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