3 ms·

You've already received a lot of good answers and some of them go into the underlying mechanics. Here is a simplistic ("business") explanation to go with them:

You've already received a lot of good answers and some of them go into the underlying mechanics. Here is a simplistic ("business") explanation to go with them: If too much power is being produced the system will eventually fail and everything will go dark. The entity responsible for the system, the system operator, will pay someone to produce less in order to prevent that from happening. As you can imagine most producers are happy to receive more money for producing less!

onetimemanytime 8y ago
I understand the business side. Burning coal or spending water to produce something that is not selling or has a negative value (we pay you to use it) is not a good strategy, but I didn't know that it can be done in real time...given the speed of light.
- tofflos 8y ago
  Ah, then you're into mechanics. Excess power is continuously converted into increased rotational speed of a very large turbine at a hydro power plant. But the increase in speed takes some time due to inertia. The hydro plant operator has a device attached to the turbine, a regulator, that reduces the flow of water running through the turbines in real-time - lowering the amount of power going into the system which in turn slows down the turbine. This service is the foundation of a working power system and is called "automatic" or "primary" regulation. Usually the system operator pays ahead of time for this service to be available followed by an additional payment afterwards for actual use. A single hydro plant can only do so much though - it can not reduce the flow of water below zero and the system will fail if it ever runs out of primary regulation reserves. The system operator will then have to pay an additional party to produce less in order to prevent that from happening. This is called "secondary" or "tertiary" regulation and is not real-time.

onetimemanytime 8y ago

I understand the business side. Burning coal or spending water to produce something that is not selling or has a negative value (we pay you to use it) is not a good strategy, but I didn't know that it can be done in real time...given the speed of light.

tofflos 8y ago
Ah, then you're into mechanics. Excess power is continuously converted into increased rotational speed of a very large turbine at a hydro power plant. But the increase in speed takes some time due to inertia. The hydro plant operator has a device attached to the turbine, a regulator, that reduces the flow of water running through the turbines in real-time - lowering the amount of power going into the system which in turn slows down the turbine. This service is the foundation of a working power system and is called "automatic" or "primary" regulation. Usually the system operator pays ahead of time for this service to be available followed by an additional payment afterwards for actual use. A single hydro plant can only do so much though - it can not reduce the flow of water below zero and the system will fail if it ever runs out of primary regulation reserves. The system operator will then have to pay an additional party to produce less in order to prevent that from happening. This is called "secondary" or "tertiary" regulation and is not real-time.