4 ms·

Yes, this function exists in some fashion in every grid (although the economic setup of how you're paid for that service differs widely). The problem in ERCOT

Yes, this function exists in some fashion in every grid (although the economic setup of how you're paid for that service differs widely). The problem in ERCOT is demand massively exceeding available supply over a period of days. You need to carry your primary operating reserve all the time, because you never know when a generator or transmission line may trip. When there's simply a lack of energy supply to meet demand on a steady state basis, you still have to preserve your primary reserves for other unexpected events and cannot call them in to meet longer term (30+ minutes) demand. So load shedding happens once available reserve dips below a certain threshold (generally around the single of the largest single contingency on the grid which may be the largest single generator or a line that feeds multiple large generators). ERCOT hasn't run out of primary reserve, but they are going to have to shed load in order to maintain adequate reserves. You always have to shed load before exhausting reserves, because one moves you closer to stability while the other moves you further away (consuming operating reserve). At this point, with power prices spiking to thousands of dollars per MWh, any plant that can run is running, including some that have come out of planned outage earlier to help out (and be paid handsomely). Even if you simply invoked some emergency order that "all generators must run until further notice", there simply isn't enough capacity due to the large number of generators on forced outage. There's no way out of that situation except temporary load shedding.

namibj 6y ago
Yeah, but part of our operating reserve is in form of industrial consumers. The slow (has 15 min to get to full power) tertiary reserve is partially provided by arc furnaces in steel mills. Also, going beyond this, charging spot prices to consumers (both commercial and residential) serves to align incentives. Such as dis-incentivizing the use of resistive heating for extreme cold, as the prices are correlated with the extreme cold, making alternative heating setups for extreme weather more affordable in comparison. Or, building houses so that extreme cold can be tolerated without damage by allowing pipes to be drained and the remaining sections to be heated separately, so the house as a whole can be unheated (and the people stay with friends). Longer-term predicted loads can be billed at a fixed rate, but spiky loads, especially those correlated with ones at other customers of the utility, can't be. You'd raise the prices until demand falls below the limits, instead of needing rolling blackouts. If people can't afford to take a hot shower right now, they just wait. At least in the absence of certain diseases, the human body is fine without showering for months. And as long as your building doesn't take damage, you'd gladly be payed a few thousand $ to put on really warm clothes for half a week. And depending on the details, you'd even conclude it more economical to have to replace some pipes after water damage, than to keep that area heated.

namibj 6y ago

Yeah, but part of our operating reserve is in form of industrial consumers. The slow (has 15 min to get to full power) tertiary reserve is partially provided by arc furnaces in steel mills. Also, going beyond this, charging spot prices to consumers (both commercial and residential) serves to align incentives. Such as dis-incentivizing the use of resistive heating for extreme cold, as the prices are correlated with the extreme cold, making alternative heating setups for extreme weather more affordable in comparison. Or, building houses so that extreme cold can be tolerated without damage by allowing pipes to be drained and the remaining sections to be heated separately, so the house as a whole can be unheated (and the people stay with friends). Longer-term predicted loads can be billed at a fixed rate, but spiky loads, especially those correlated with ones at other customers of the utility, can't be. You'd raise the prices until demand falls below the limits, instead of needing rolling blackouts. If people can't afford to take a hot shower right now, they just wait. At least in the absence of certain diseases, the human body is fine without showering for months. And as long as your building doesn't take damage, you'd gladly be payed a few thousand $ to put on really warm clothes for half a week. And depending on the details, you'd even conclude it more economical to have to replace some pipes after water damage, than to keep that area heated.