Back when I was active on a lot of engineering discussion boards and was working to make more efficient electrolyzers there was a lot of talk about free energy. That ranks right up there with perpetual motion. But on the other hand, outside the cost of the equipment and maintenance any renewable such as wind or solar is free energy.
With that in mind I set out to design the simplest way to produce hydrogen from water utilizing energy that is available around us. I came up with several designs but the simplest was as follows;
First you would suspend a copper wire that is roughly 100 feet long about 30 feet off the ground and insulate it from the posts you are using to hold it. This will a large electric charge to build in this wire (possibly 400 volts or more). This happens because the Earth is a huge generator and there is a constant flow of electrons between the earth and the sky.
Then you drive a metal stake about 8 feet into the ground. This will be to drain off the built up charge in the suspended wire into the Earth. Does this sound like the grid? Well yeah it does except we don't need a power plant because the Earth is our source of electricity. Really the grid would be charged as it is without any power plants but it wouldn't really be a usable charge. You can think of a power plant and amplifying and fluctuating the existing charge lol
Now we build an electrolysis cell. We would use two stainless steel plates as our electrodes and some suitable glass or plastic container. We connect our suspended wire to one electrode and our ground stake to the other. We then fill the container with pure water and put our electrodes into it (one on either side with no metal to metal contact).
At this point we have created a water capacitor. There will be no current flow because water is an insulator and a dielectric. The potential difference between those two plates should be several hundred volts.
Next we add some electrolyte to our water. Some readily available choices would be sulfuric acid (H2SO4), Sodium Hydroxide (NaOH) or even baking soda (NaHCO3). These are ionic compounds which allow the water in our cell to become electrically conductive and a current to pass between our wire and the ground.
These electrolytes each require a different minimum voltage to work but they are all around 2 volts. The cell would allow the wire to drain the surplus charge of electrons off through the cell and the current flow would produce hydrogen and oxygen gases and the cell would always maintain a minimum voltage due to both the capacitive aspects of the cell and the limit of the minimum voltage requirements of the electrolyte.
If you hooked the cell up to a regenerative fuel cell so that the gases produced in the cell would be delivered to the fuel cell then you could power something like an LED light (the amounts of gases produced would probably be small). But that LED light would burn 24/7 essentially forever (until the system wore out). A regenerative fuel cell combines H2 and O2 gases and the resulting water would run back down to your electrolysis cell. You could use the fuel cell itself as the electrolyzer but then it would be doing both functions at once and I don't think that would work lol.
I kind of want to build one of these systems as an art piece somewhere and just have the light burning as a memorial to human ingenuity. I don't think there is any real commercial application for this device but it would be a great piece of art. And you could substitute a copper plate for the suspended wire and it would still probably work. I designed this as an example that free energy does exist and that there are many more things possible than we have yet thought of.