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A random nitpick that you might find interesting: in fact unused electricity is not "simply lost." Where would it go? Because of the law of conservation of en

A random nitpick that you might find interesting: in fact unused electricity is not "simply lost." Where would it go? Because of the law of conservation of energy, it would have to go somewhere, and we're talking about what might be a lot of energy. Electrical systems actually must generate exactly the required amount of electricity at all times. One particularly interesting tidbit I learned in one of my engineering classes: hydro dams are like giant capacitors. If you can't "push" more energy into the power grid, then you also can't push more water through the turbines; it gets harder to turn the turbines due to electromagnetism. And so the dam starts to fill up, more or less automatically, because of the laws of physics.

AgentConundrum 16y ago
Well, now I feel like an idiot. That comment was based on a poorly recalled statement regarding the ineffectiveness of Earth Hour. If you don't use electricity, it'll flow to the next guy, so your lack of use doesn't really have any effect. Still, you need to generate enough electricity to cover everyone's potential needs. Whether that electricity is used or not (where not means that unused electricity dissipates as heat or.. whatever happens to unused electicity?), it still needs to be available, and at a cost. Unused bandwidth doesn't need to be generated. It's simply a quiet line. Thanks for reintroducing logic to my brain. The rest of my argument mostly holds up though, right?
- Nick_C 16y ago
  > whatever happens to unused electicity? Re-orient your thinking a little and it will make sense. We're talking AC systems (not a SWER) so it is a closed-loop as far as the electricity is concerned. The electricity doesn't go anywhere, it constantly oscillates. What you are actually generating in a meta sense is ability to do work. You are overcoming the electrical resistance from all those users' machines doing work. Does that analogy help?
  - AgentConundrum 16y ago
    I understand the closed loop. I did a bit of research when I wrote my last comment and when I read that line is when I realized how dumb I was. So.. electricity gets pumped into the grid from some power station, and then [a given unit of electricity] loops repeatedly around the loop until it's either consumed by an appliance or is converted to heat by the resistance inherent to the transmission lines themselves?
dhimes 16y ago
One particularly interesting tidbit I learned in one of my engineering classes: hydro dams are like giant capacitors. If you can't "push" more energy into the power grid, then you also can't push more water through the turbines; it gets harder to turn the turbines due to electromagnetism. In dynamo-generated power it's harder to turn the tubines when the electricity is "used," that is, when there is current flowing. The more current that is flowing the harder they are to turn. Turning the wires of the coil in the magnetic field sets up an emf. If you allow that emf to drive a current, you now have current-carrying wires moving through a magnetic field feeling a force opposite their motion. This is felt as resistance by whatever is driving the turbine. So, when you "use" the electricity the turbines are harder to turn, not easier. This also makes sense in terms of conservation of energy. You are taking the energy out of the water and using it to power the users connected to the electric grid. The more power you want to supply, the more you must take out of the water (or steam, if you are using steam to drive the turbines). So the inability to push more water through the turbine is due to the turbine delivering max current (that is, it is at full load). Any less load means less current and less resistance. In fact I understand (not an expert on their construction) that it is a problem when the load reduces at some types of plants because you are still driving the turbines with the same fuel but their resistance drops. You have to adjust the fuel to the turbines to keep everything balanced. With Nukes this may be a slow processess, so that is perhaps why you hear of plants "dumping" energy-- using it in some (wasted) way just to keep the current in the coils high enough to provide resistance to whatever is driving the turbines. I've heard of places that pump water into elevated storage so as to use it again when demand suddenly picks up- kind of a capacitor effect- but I don't know anything about it first-hand.

AgentConundrum 16y ago

Well, now I feel like an idiot. That comment was based on a poorly recalled statement regarding the ineffectiveness of Earth Hour. If you don't use electricity, it'll flow to the next guy, so your lack of use doesn't really have any effect. Still, you need to generate enough electricity to cover everyone's potential needs. Whether that electricity is used or not (where not means that unused electricity dissipates as heat or.. whatever happens to unused electicity?), it still needs to be available, and at a cost. Unused bandwidth doesn't need to be generated. It's simply a quiet line. Thanks for reintroducing logic to my brain. The rest of my argument mostly holds up though, right?

Nick_C 16y ago
> whatever happens to unused electicity? Re-orient your thinking a little and it will make sense. We're talking AC systems (not a SWER) so it is a closed-loop as far as the electricity is concerned. The electricity doesn't go anywhere, it constantly oscillates. What you are actually generating in a meta sense is ability to do work. You are overcoming the electrical resistance from all those users' machines doing work. Does that analogy help?
- AgentConundrum 16y ago
  I understand the closed loop. I did a bit of research when I wrote my last comment and when I read that line is when I realized how dumb I was. So.. electricity gets pumped into the grid from some power station, and then [a given unit of electricity] loops repeatedly around the loop until it's either consumed by an appliance or is converted to heat by the resistance inherent to the transmission lines themselves?

dhimes 16y ago

One particularly interesting tidbit I learned in one of my engineering classes: hydro dams are like giant capacitors. If you can't "push" more energy into the power grid, then you also can't push more water through the turbines; it gets harder to turn the turbines due to electromagnetism. In dynamo-generated power it's harder to turn the tubines when the electricity is "used," that is, when there is current flowing. The more current that is flowing the harder they are to turn. Turning the wires of the coil in the magnetic field sets up an emf. If you allow that emf to drive a current, you now have current-carrying wires moving through a magnetic field feeling a force opposite their motion. This is felt as resistance by whatever is driving the turbine. So, when you "use" the electricity the turbines are harder to turn, not easier. This also makes sense in terms of conservation of energy. You are taking the energy out of the water and using it to power the users connected to the electric grid. The more power you want to supply, the more you must take out of the water (or steam, if you are using steam to drive the turbines). So the inability to push more water through the turbine is due to the turbine delivering max current (that is, it is at full load). Any less load means less current and less resistance. In fact I understand (not an expert on their construction) that it is a problem when the load reduces at some types of plants because you are still driving the turbines with the same fuel but their resistance drops. You have to adjust the fuel to the turbines to keep everything balanced. With Nukes this may be a slow processess, so that is perhaps why you hear of plants "dumping" energy-- using it in some (wasted) way just to keep the current in the coils high enough to provide resistance to whatever is driving the turbines. I've heard of places that pump water into elevated storage so as to use it again when demand suddenly picks up- kind of a capacitor effect- but I don't know anything about it first-hand.