Generators are turned on/off via pricing signals, in advance a generator makes known how much money /MWh it will take for them to turn on and scale to various levels of output.
A control dispatch system monitors/estimates demand and sends pricing signals to the generators in an effort to match that demand. So reducing price when there's oversupply and increasing price when there's undersupply in an effort to balance load demand and generation supply.
Nuclear and coal plants produce a baseline output when they're on and take a long-time to turn on/off so their baseline bid is nearly zero. As long as they get a penny for a MWh they'll stay on because they make their profit in they high demand hours.
In a system without wind (solar is less of an issue because it's easier to predict) this design works fairly well at moderating power generation relative to demand.
Adding a renewable that's not properly predicted to this system for a few hours leads it to try to "turn off" some baseline generation if these hours are already low generation. If that baseline is priced close to zero then the pricing has to go negative.
A control dispatch system monitors/estimates demand and sends pricing signals to the generators in an effort to match that demand. So reducing price when there's oversupply and increasing price when there's undersupply in an effort to balance load demand and generation supply.
Nuclear and coal plants produce a baseline output when they're on and take a long-time to turn on/off so their baseline bid is nearly zero. As long as they get a penny for a MWh they'll stay on because they make their profit in they high demand hours.
In a system without wind (solar is less of an issue because it's easier to predict) this design works fairly well at moderating power generation relative to demand.
Adding a renewable that's not properly predicted to this system for a few hours leads it to try to "turn off" some baseline generation if these hours are already low generation. If that baseline is priced close to zero then the pricing has to go negative.
Hope that makes sense.