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How much electricity does consume electric system by itself? Just to have an option at any moment to plug in anything at socket at home and turn it on. There are huge power plants to convert high voltage to much lower values (220/110V) and off-course they are with energy conversion efficiency < 100%.

What will happen if suddenly huge amount of power consumers just turn off EVERYTHING. (For example - Earth Hour, but not just the simple citizens turning off few lamps - completely everything, all huge factories, trains, traffic lights, street lights - total consumption blackout).

And the situation is - the electricity production is the same, but the only working unit is electrical system by itself - nothing plugged in, but it is functional.

Does the power grid something like huge heaters/huge engines - just to consume excess of the electricity power and keep system online without damaging?

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    \$\begingroup\$ I’m voting to close this question because based on unrealistic premise. This is not engineering. \$\endgroup\$ – RoyC Dec 17 '20 at 16:44
  • \$\begingroup\$ @RoyC but what about how many power consume power grid by itself? \$\endgroup\$ – XuMuK Dec 17 '20 at 16:54
  • \$\begingroup\$ And the situation is - the electricity production is the same - no it isn't. Voting to close also on unrealistic premise. \$\endgroup\$ – Andy aka Dec 17 '20 at 16:54
  • \$\begingroup\$ "What is the power consumed internal to the grid" is a potentially answerable question, and doesn't need the complication of turning off all the consumers. \$\endgroup\$ – pjc50 Dec 17 '20 at 17:11
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Curiously, a blackout would occur. All generating stations, suddenly bereft of demand, will spin faster, voltage will rise, so their protections will trip, shutting them off-line. This happened to some of the stations during the 2003 North American blackout when the grid separations occurred.

The funny thing is that it would take quite a while to get the grid back on, even though there is no demand, simply because the whole of the grid is off (this is called a black start).

Realistically, however, it would be hard to turn off everything. Hospitals, sewage treatment plants, ventilation in tunnels? You don't really want to shut down these, ever.

EDIT:

but what about how many power consume power grid by itself?

Unfortunately, even if we kind of made people turn off everything, we won't find out with this method.

Since a blackout would quickly ensue, whatever resources the grid used previously will quickly dwindle down. A lot of plants will run on backup power (e.g. nuclear reactors need cooling after SCRAM), but the backup power would be provided locally, so the concept of a grid does not really apply. Also, the power usage for cooling, circulation, etc. would be reduced - backup power is used for essential systems only.

A grid running at full power has some losses, e.g. resistive losses in the conductors, however this is not consumed by the grid, it is just losses (and they vary with load and temperature).

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  • \$\begingroup\$ This is very good answer! So the power grid is not consuming anything, it just looses. \$\endgroup\$ – XuMuK Dec 17 '20 at 17:18
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    \$\begingroup\$ Rather than just saying "that can't happen", could you start with the assumption that enough generating capacity could be shed in a controlled manner so that voltage could be maintained at no-load, and say what would happen? Or is there a reason why, even if said generator-shedding happened, one still couldn't maintain the grid with no draw? \$\endgroup\$ – TimWescott Dec 17 '20 at 18:58
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    \$\begingroup\$ "it would be hard to turn off everything." You don't have to actually turn it off -- just disconnect it from the grid. Most of the critical stuff has backup systems with the option to manually disconnect from the grid, so it's feasible. \$\endgroup\$ – LShaver Dec 17 '20 at 19:16
  • \$\begingroup\$ @TimWescott, I think the grid will be extremely unstable without load. \$\endgroup\$ – anrieff Dec 17 '20 at 20:28
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    \$\begingroup\$ @LShaver, my reasoning is it would be more politically hard. I mean we can all live for a while without A/C, lighting, computers, elevators, factories, and so forth, but for some critical things it would be exceedingly difficult to persuade people turning it off is justified. Yes, backups exist, but backups can fail and then real people could die. Nobody is taking that risk, even for Earth Hour or whatever other cause. \$\endgroup\$ – anrieff Dec 17 '20 at 20:34
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If by "the grid" you include ALL aspects of power transmission and distribution (not just the wires), and by "consume" you include losses, I'd guess it is somewhere in the area 3-5% of the available capacity is consumed in transformer magnetizing energy and cable losses supplying that.

But of course, there are switch systems that would disconnect unused equipment at some point so as to avoid those losses, so the "available capacity" would be constantly cascading downward until there basically is no more "grid" that is powered at all, ergo no losses! That's why it's really not that simple of a question.

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What will happen if suddenly huge amount of power consumers just turn off EVERYTHING. (For example - Earth Hour, but not just the simple citizens turning off few lamps - completely everything, all huge factories, trains, traffic lights, street lights - total consumption blackout).

Well, as mentioned, currently the grid blinks off to protect everything from overvoltage.

It's conceivable that you could design the grid to handle all of the point-of-use devices being turned off, if not all at once then perhaps in stages. In this case you'd either have all the generators running but at reduced field excitation, or you'd turn off some generators. In either case, all of the transformers in all of the substations would still be consuming power, as would all of the transmission lines.

And the situation is - the electricity production is the same, but the only working unit is electrical system by itself - nothing plugged in, but it is functional.

According to this randomly selected page, the typical efficiency of the grid is around 93%. If I make the rash assumption that half of that is resistive and the other have is exciting transformers, corona loss, and other "voltage related" losses, then the grid would consume about 4% of its total capacity just sitting there.

Does the power grid something like huge heaters/huge engines - just to consume excess of the electricity power and keep system online without damaging?

Not in the US, to my knowledge. It would be cheaper to design the grid to remove or otherwise disable individual generators as needed. However, power rates vary by demand, and there have always been industries that spin up more capacity when power is cheap, and spin it down when power is expensive. There's also some power storage schemes out there that attempt to store power off the grid when its cheap, and sell it back when its expensive.

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