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by mikbp
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I read somewhere a comment claiming that a "water engine" (Stanley Meyer's fuel cell) is possible. Wikipedia calls it a perpetual motion machine, but a quick search indicates that the guy just claimed it used water as fuel (nothing about it producing more energy than it consumed).

The thing is that the topic is very prone to conspiracy-story telling (plus the guy died young), and I don't have the will and time to separate the wheat from the chaff.

Has anyone read about it and can make a nice review of the topic?

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Stanley Meyer's water fuel cell
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Brendan Long

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Stanley Meyer's fuel cell isn't using water as fuel, it's using hydrogen as fuel, but the way it produces hydrogen (using electricity to separate water into oxygen and hydrogen) takes more power than burning the hydrogen produces (because of energy lost to heat in the process).

Because it already requires electricity anyway, the water part is pointless and it's more efficient and simpler to just run an electric motor directly.

It's kind of like if you took a shopping cart and threw rocks at it to push it along, then claimed you invented a shopping cart that uses rocks as fuel. Technically the rocks are pushing the shopping cart, but the source of energy is your arm.

[-]Richard_Kennaway40

I don't know anything about Stanley Meyer's fuel cell, but turning electricity into hydrogen could be a way of storing the energy. Does it make any economic sense from that point of view?

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2Brendan Long
I'm not an expert on this but I've heard that hydrogen storage can be useful in some cases. It's not very efficient, but there's plausibly cases where it doesn't matter (like storing excessive power overnight from nuclear plants or excess power during the day from solar). It would have to compete with other storage solutions like batteries, molten salt, producing other fuels like natural gas, pumped storage, etc. though. When comparing it to other storage methods, it's important to keep in mind that hydrogen is a gas a room temperature, so it takes up a lot of space unless you use high-pressure and/or cryogenic temperatures to make it more dense. In case you're curious, some other use for hydrogen (even if producing it is inefficient) are industrial processes that need extremely-high temperatures (like steel production) and chemical processes that need hydrogen (like ammonia production).
1mikbp
It is not easy to store it for longer time, but that's one of the uses of hydrogen (for energy).
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[-]Dagon2-1

Just read the wikipedia article (https://en.wikipedia.org/wiki/Stanley_Meyer%27s_water_fuel_cell).  What made you think this was worth asking about, let alone that it's worth someone else's time to "make a nice review of the topic"?

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[-]mikbp10

I only skimmed it as well as an article. I think it is quite likely that someone here has been very curios about this is a topic and would be happy to write about it. It is just a question, so why not asking? I am not forcing anyone to answer it or even to read the question (and I have willingly make it short).

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