Why can't we store electricity in water?

Emmanuel,
Please read the reply below that I wrote a few years ago, but perhaps I can expand on the metaphor a little more.

Consider if I asked you to store fire. I have a campfire going right here, some logs are burning, just go ahead and catch some so we can save it for later.

It's impossible, right? The fire isn't a substance, it's the release of energy in the form of light and heat that results from the hydrocarbons (molecules containing chiefly carbon and hydrogen) in the wood being broken apart and recombining with oxygen from the air to form carbon dioxide and water vapor. The wood doesn't burn normally because it takes a certain level of heat to start the process, but once going, there is plenty of heat available to keep it going. In this sense, does the log count as stored fire? Does a match count?

A battery is "stored" electricity because the imbalance between the two terminals is "ready to go" current as soon as the circuit is connected. However, the unconnected battery does not "contain" electric current any more than an unlit match "contains" fire.

Consider if I asked you store a sound. Sound is just waves of vibrations in the air. We can detect those vibrations with our ears, or with a microphone. Our ears convert the vibrations to an electric signal that our brain understands. A microphone converts the vibrations to an electric signal that can be converted to other things and recorded, and then reversing the process recreate the original sound. However, you can't store the vibrations of air. You can capture air in a bottle, but the vibrations are not the air itself, they are just IN the air. The recording is not the storage of air vibrations, it's the storage of something the vibrations were converted into.

Much like a battery stores the imbalance of electrons that will create electric current, and can be created from electric current (charging the battery) but is not itself electric current. Copper wire, or water, or any other electric conductor, is just the medium through which electrons move about, like sound waves in air. The movement itself cannot be held, only converted.

Or an even sillier, more basic example, can we drive a car along an ordinary asphalt road, store the movement of the car in the road, and use it to power another car? No, because the road has nothing to do with what makes the car move.

A. Hi, Seema.

Please try to explain the context in which water has +Ve and -Ve charge, and what 'store electricity' means to you. I don't quite understand the question and I'm not real confident that you do either :-)

But if you can make the question a bit clearer, I think we can help. Certainly we can 'store energy' in the form of hydrogen electrolytically liberated from water.

Regards,

A. Do a google search of capacitors. You will find at least one article that talks about it storing a charge. Actually, they decided that the charge was stored only at the glass/water interface if I remember correctly. It is a tiny charge, probably in the nano Farad range, possibly in the micro Farad ranges.
I think that you will find that for the bulk of the water mass, that even tho it does have a + end and a - end to the molecule, that it is quite happy to share the charge rather than store it. As Ted said, when you add electrons to water, it will break the bond and form H and O gasses.

A. There are several ways in which energy can be stored in water. I can think of the following:
1. "Pure" water can be used as a dielectric in a capacitor which stores energy.
2. You can heat water and store (thermal) energy. Being in Bangalore you should be taking hot water bath daily! Energy is also stored in steam to run electric generators.
3.Potential energy stored in water in dams is converted into kinetic energy and then to electric energy in hydroelectric power stations.

Can you identify the source of energy in each of these?

Q. Why can't we use a double sided wind mill in generation of electricity?

A. Hi, Suryateja. I think you *can* use double-sided wind mills.

Are you sure that you fully understand this question? Please remember that it is smart to ask for help in answering questions that you may have, but usually less smart to ask a question that you don't understand; that can be wasting your opportunities for education -- please tell your teacher when you don't clearly understand a question. Good luck.

Regards,

A. Hi Anthony. Although I don't think that could actually work with most batteries, thinking outside the box is always a good idea!

Regards,

A. Is it worth explaining here that "electricity" isn't a substance that can be held or stored like coal or gasoline?

Electric current is the movement of electrons along a conductor (usually a copper wire). It can be electrons going from one end to the other (direct current) or back and forth along a short stretch over and over (alternating current).

Direct current is produced by a battery, which has one side that is holding a lot of extra electrons, the other side that is "missing" a lot of electrons, and a semi-permeable membrane or salt bridge between them to keep other things balanced that need to be. Solar panels can also produce direct current by using light rays to knock electrons around and forcing them to run along the wire to get back "home".

Alternating current is produced by spinning a ring of magnets around one section of the wire. Usually the magnet ring is being driven by steam that is generated by burning coal or busting uranium atoms into pieces, or sometimes by wind power or water moving through a dam.

So since electric current is all about motion, you can no more store it than you can the energy of a speeding bullet. You can have that bullet in your gun ready to go, but once you fire it, you can't pause and unpause it.

A. Many years ago, I did a lot of experimenting with anodic and cathodic ion-exchange membranes. One time, I arranged several small, clear, plastic tanks (about 100 ml each), containing various solutions, in a line, each separated by membranes, with electrodes at the ends. My object in one experiment was to set the positive and negative ions in one of the cells out of balance, to produce an over-abundance of either positive or negative ions so that the solution in that cell would have an over-all positive or negative charge. My idea was to be able to store whatever energy this imbalance would produce. Ultimately, I wondered what would happen if one combined a positive ion rich solution with a negative ion rich solution. Would energy be released?

The experiment worked, as far as my setup being able to produce this ion imbalance. However, nature would not allow this to happen. To make up for the charge deficit in the cell, it automatically split water off one of the membrane surfaces in that particular cell, continually. I could visually see it happening as bubbles (H2 or O2) coming off of a single point on the membrane. If I was producing more positive than negative ions, water split and gave off H2 gas and OH- ions, to make up for the deficit. If the solution were negative ion rich, the water split to give off O2 gas and H+ ions. In other words, I could not store energy in a solution, at least not in the way I was trying to do it. If it had worked, I might have blown up the lab. It was a complete surprise the way nature prevented me from doing it.

A. Our traditional automobiles work on I.C. engines where they made an arrangement such that they convert the combustion fuel energy to mechanical, so could there be chance of replacing these fuels with charged liquids (maybe something that could just explode on compression or some kind of electron-proton unbalanced reaction), simply a controlled explosion.