If i were to build a dam in a river, to focus the flow of the water and try to harness it. I guess i would create some sort of wheel that would be spun by the power of the water. How do i turn this into energy and eventually even store it?
In: Engineering
You need a generator or an alternator. They use magnets and coils of wire to turn mechanical work (turning the wheel) into electrical energy.
I think making something like Hydrogen is one of the better ways to store energy if you absolutely have to store it. Burning Hydrogen is “green” as the product is just water and you can burn it in fuel cells making electricity without intermediate steps. Main issue is that Hydrogen takes up way too much space, but it’s not as important if you can set up a facility for it.
Converting rotational momentum of a turbine into electricity is pretty easy, copper coils and magnets do the job for you.
In general, storing energy is hard and prohibitively expensive, people usually use energy as is right away and just produce more when needed.
One way would just to be hold back as much water as you can, and then release it to generate the amount of electricity you need at that given moment.
To force electrons to move through a wire, you move a magnet along a wire. Many materials will conduct electrons, but copper is the best all-around material for that, so let’s look at a copper atom
An atom has a blob in the center, like the sun, and it’s made up of protons and neutrons. All you need to know for electricity is that electrons orbit the nucleus, just like planets around the sun.
Each element has a different number of protons, neutrons, and electrons. Copper has 29 electrons per atom.
Electrons can be pulled out of an atom and shoved into the next atom by moving a strong magnet near it..
Imagine a row of copper atoms in-line along a section of copper wire. When they are at rest, each atom has 29 electrons. However, when you pass a strong magnet along the wire, just behind the magnet the copper atoms have 28 electrons, and just under the magnet, the copper atoms have 30 electrons.
Current will only flow if there is a continuous loop, called a circuit. When you turn a switch on, you are closing the switch-air-gap, and completing a circuit.
Now when you move the magnet, the copper atoms with 30 electrons are pushing electrons ahead of them to flow away from the magnet (so they can get back to 29 electrons), and the copper atoms behind the magnet with 28 electrons are pulling the electrons from the circuit to bring them back up to 29 electrons, which is where the copper atom is in balance with all its forces being stable.
Since its impractical to move magnets along a long straight wire, the copper wire is cleverly packaged into coils, and they are arranged in a circle like the numbers on an old analog clock.
Depending on how the internals are configured, this device could be called a generator, an alternator, or a dynamo.
Imagine you have a long line of golf balls, all touching and side by side. This is a wire, lets say its a copper wire because copper is easy to make into the long wire and its something the imaginary golf balls have an easy time rolling in (it could also be made from steel and some other metals). These golf balls are electrons, a metal, like copper, is an element whose electrons can “move” around.
If we push on the balls without them rolling (imagine on the other end something was blocking the way that will move if you push hard enough) we have just created Voltage, its the pressure pushing on the electrons. If they move we have Amperage, the number of electrons that move or flow down the line. How hard we have to push is the Resistance.
Now, we can’t just push the golf balls into nothing, that would make empty spots in our line and it wouldnt be a line anymore. So imagine the line goes off into the distance and comes twisting back around so that the other end is touching our starting spot. Now you can see that by pushing the balls forward they will roll like a train and fill up the spot where you moved them from. This is the flow of electricity, electrons move out but simultaneously move in from the other way. We could say the direction they go is positive and the direction they come from is negative.
Now let’s create some power. Magnets, or actually the magnetic field magnets make can gently push on those balls without touching them, very useful! If we spin the magnet we can push one ball forward every spin. This is nice but its not a lot, so let’s take our wire, the long line of balls, and wrap it around outside the spinning magnet many, many, many times. Now when the magnet spins it can push alot of balls at once and with a lot of pressure. We need a way to keep the magnet spinning, we could do it by hand but that isnt a real job. So lets hook the magnet up to a big fan and spin the fan. We could use wind, or steam (coal, gas, nuclear all heat up water to make steam to push the fan to turn the magnet) or we can use flowing water. We could also make a special type of wire that makes sunlight move the electrons but we can focus on the basics.
Now we have a big spinning magnet and lots of wire pushing electron and creating electricity. We can do way to many things with it for me to cover everything, but ill be happy to answer specifics. As for how to store it, we can use batteries. We actually use so much electricity that our magnets are practically spinning all the time, but sometimes we need batteries. There’s many types, but the basic idea is to take two different metals and submerge them in an acid. The acid has holes in it that want to be filled with electrons and the two metals have plenty to give. So if we add electricity to the battery it will “charge” and fill up all its spots. We can then take electricity from battery by connecting to it later. The actual number of electrons in the battery doesn’t go up or down they just change locations from the acid to the metal and back.
Usually water wheel type generators don’t require the electricity to be stored because the wheel is always running. That is as long as your source of water is continuous throughout the year.
One more idea- You could use the kinetic energy of the falling water and store it in a mechanical battery as rotational energy – aka use a flywheel-to then generate electricity with at a later time.
But as someone pointed out- hydroelectric is assumed to be fairly constantly available
https://en.m.wikipedia.org/wiki/Flywheel_energy_storage
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