this post was submitted on 09 Apr 2024
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Thats literally what a "ground" is electrically. The ground.
We literally design electrical systems to do exactly this, all day long. You can literally "dump power into the ground."
No, you can't.
The ground in a circuit doesn't dissipate energy
the energy gets dissipated elsewhere. That's what ground is: it's what we call the electrical part of a circuit where the energy has already been dissipated (I'm being a little casual with my electricity, but I think it's a valid statement nonetheless
ground is defined as the zero potential).
You can try this out by plugging a wire from hot to ground in your house (please don't do this). The energy gets dissipated in the wires. This is bad, because it is a lot of energy dissipated very quickly. Best case you throw the breaker. Worst case you burn down your house.
You can run it through a very large grid of aluminum fins which get hot, and you know, I don't know, boil water with it or something to be used for uh, purposes, such as heated water. :)
So... You can use it. As exactly described. By the description of the problem.
Sorry for being snarky, but this is exactly what the "paying people to use your energy" part of this situation is.
Yep absolutely
a few kW? I can burn that no problem. A MW? Well...that takes a little more thought. A GW? That's a whole different ballgame.
Haha, thanks for taking my comment with humor and stride. Yeah, you're right. I still think having too much energy is a good problem to have overall.
I do microsolar and when my batteries are full (rare), I just unplug them. The solar panels just sit baking in the sun, and then cool off at night.
What is microsolar? Tried looking it up, didn’t come up with much.
It's having a very small (typically less than 2 kW) solar system
It's weird that that's possible as such an easy solution, and all those electrical engineers never thought to use it, instead putting in load banks and all sorts of contrivances to heat metal in an emergency, or find complex ways to hide excess production in normal load and balance production by managing the generators.
Even weirder that the people who run solar grids opted to pay people to take excess power rather than just dumping it on the ground, although a lot of them have also taken to heating metal instead, or water for smaller home setups.
Yes, you can technically connect your generator directly to the ground. This isn't something people want to do because it can damage equipment.
It's why that heating metal trick is used as part of the emergency shutdown rather than as part of load regulation, and they don't want to use it because they have to make sure the right bit of metal melted.
None of this has anything to do with people needing to react to excess current in an electrical grid, and not just let it be a situation that happens. It requires intervention was the point of the phrase.
As a professional engineer who literally designs solar power plants for a living, this is not how electricity works. It is true that solar inverters can throttle their output by operating at non-optimal voltages, but you can't just dump power into the ground without causing major issues to the grid infrastructure.
Why?
I'm not doubting you, I'm just a big curious nerd
In an ideal picture, ground isn't where energy gets dissipated
there's no such thing as "dumping energy to ground" (or if you prefer, everything is "dumping energy to ground").
If ground dissipates significant energy, this has all sorts of Very Bad implications. For starters, the ground can no longer be at uniform potential if it dissipates
so now we have a ground that isn't actually at ground! (This just follows from Ohm's law.)
Another way of stating this is to imagine what sort of circuit you need to "dump energy to ground." This is probably just a wire connecting hot to ground
but what happens if you do this in your home, i.e., plug a wire from hot to ground (please do not do this!)? It gets really, really hot, and will probably either throw the breaker, melt, or start a fire. The reason it gets hot is because it's the wire that dissipated the energy.
Ok. So the reason the wire gets hot is because it has finite resistance. So what if we choose an imaginary superconductor instead? Well, now we're trying to draw infinite power, which is bad! In practice of course it won't be infinite, and will be determined by the resistance of the power lines feeding it. But remember that wire that got really hot? Now we're treating the power lines that way. So this is really not good, and besides, we wanted to use a controlled amount of power, which this clearly isn't.
So, we can be smarter here and add some resistance to our load
instead of a wire from hot to ground, we now have maybe a coil of low-but-finite resistance wire. This works great, and it's just a resistive heater.
The problem isn't dumping energy at a human scale (e.g., an individual space heater)
the problem is when you have excess power on an industrial scale.
If all the energy is actually being released by the wire through resistance, then why's the potential of the ground changing?
The potential at the ground isn't (or shouldn't) be changing
which is the same thing as saying the power isn't being dissipated in the ground. So the power isn't being "dumped to ground," it's being dumped through the wire.
So basically, two options: 1) you dissipate power in the load, which is what should happen, and everyone is happy. 2) you dissipate power across your ground, which means ground is no longer really ground, and all sorts of nasty and dangerous things can happen.
Does lightning cause those nasty things to happen?
I think so. A huge amount of energy is now trying to get to ground. Power will now be dissipated across the ground (so, from the lightning rod to the earth). This is bad ("ground" is no longer at ground potential everywhere), but probably not as bad as the alternative.
I think one way to think about it is that, ideally, ground is a single point in a circuit that is defined to be at zero potential, always. Anything that appreciably violates this assumption causes bad things to happen, though often the bad things are subtle/not that bad (e.g., your guitar amp starts buzzing more than you want).
A chance for @bradorsomething, son of Gondor, to show his quality!
When we refer to the grounded conductor (the neutral), it does have a reference to the ground potential of the building receiving power. But the current generated by the power plant seeks the least resistive path back to its source, and the grounded conductor provides a path back to the generation plant that carries no voltage potential for electricity to draw towards or away from - the wire simply accepts the flow of energy to or from the power plant, to complete the circuit without changing the voltage potential.
There is also a grounding wire, which is green or bare, which is present in building in the US to allow anything electrified by stray wires to complete the circuit and trip the breakers in the panel. This wire joins to the grounded conductor (the white colored neutral) at the main panel where the utility provides power… utilities use the neutral as their ground, so current completes the circuit back to the power plant through the neutral.
When I say “the circuit looks for a path back to its source,” I’m playing a little fast and loose here… the current seeks the most potential to complete the circuit pathway. This path is almost always the return path to the power plant.
Join us next week, when I explain that lightning doesn’t care much about our wire at all, because at that scale it’s like the ocean caring about a moat at a sand castle!
If you could do that there'd be tones to research going on about how to extract the energy stored in the ground as the storage capacity would in many orders of magnitude greater than we have now. We'd also be probably capturing the energy released in thunderstorms.