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StandardSudden1283 t1_iyh0ihh wrote

Reply to comment by Ann_not_a_cult_er in New device can make hydrogen when dunked in salt water by TurretLauncher

2nd law of thermodynamics.

You'll never get more out of electrolysis than it requires

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Black_Moons t1_iyh9lmp wrote

This. If you use an IEC engine to burn hydrogen... you end up with: WATER!

You can't extract energy from turning water into something that gets turned back into water, because you ended up with the exact same substance you started with.

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LucyEleanor t1_iyir4d1 wrote

Plus lose alot of energy to heat.

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Black_Moons t1_iyj886d wrote

Yep. Electrolysis is very inefficient. But even if you made it 100% efficient, and somehow made an IEC engine 100% efficient, you'd still only be making an energy storage system at best.

Realistically, the above two systems are like, 60% and 30% efficient at best? So your talking 18% overall. Not really worth doing until we have so much renewable energy that what to do with all the extra between the hours of X and Y becomes an issue.

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LucyEleanor t1_iyj90yp wrote

We can make hydrogen fuel cell systems smaller and lighter than normal ice's though, so atleast they have their use in drones.

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ledow t1_iyjjd6o wrote

Hydrogen needs to be stored at 10,000 psi to come anywhere NEAR the energy density of a conventional fuel.

Though you can get more energy per kilo of hydrogen, you can't do that without basically compressing it to enormous pressures or taking up a ton of room, or using up lots of chemicals and energy to lock it into other substances (which add to the mass).

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LucyEleanor t1_iyjjhkb wrote

Well drones do use mini scuba tank guys full of compressed h2. Idk the psi tho

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[deleted] t1_iykisj3 wrote

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Black_Moons t1_iykond6 wrote

that is a really inefficient way of storing energy. about 18% efficiency after electrolysis and internal combustion engine.

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[deleted] t1_iykstc9 wrote

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Black_Moons t1_iykx3l8 wrote

Reshape heavy energy consumer industry like cement plants, aluminum smelters, ammonia production, etc to run during peak hours only, by giving them better per-hour pricing so instead of drawing power 24/7 and requiring baseload generation, they can run off peak hour renewables and enjoy lower costs of energy. They will have to increase facility size to compensate for lower productivity however.

Also, redox flow batteries arnt half bad..

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