PJM has most of their training materials on line.[1] Those give a sense of how PJM does it. Start with "PJM 101", "Generation Basics", and "How PJM operates and dispatches".
PJM has a day-ahead market, where most of the capacity is booked a day in advance, and a real-time market, where differences from the predicted load are handled. This allows everybody involved to plan ahead a day. There's also "non-economic operation", where, in the event of big problems, the PJM control center just tells generators what to do. That's for emergencies.
All generators post not just a single price, but a price/output curve. Generators also post a "ramp rate"; how fast they can ramp output up or down on request. PJM's job is to optimize all this, which happens on about a five minute cycle. There are also lots of physical constraints - transmission lines and substations can only handle so much power, and policy is to run the system so that any single failure won't take it down. After a failure, the transmission system is reconfigured to become single-point failure tolerant again. There's a control room in Valley Forge, PA, (and a backup control room somewhere else) where about ten people control the wholesale power grid.
California had, briefly, a system with an spot power auction every half hour, with dealers who weren't generators or power consumers, but that was abused and produced blackouts, along with the bankruptcy of PG&E. California now has a day-ahead market and a spot market for fine tuning, like PJM, which resulted in much saner operation. So does ERCOT, the Texas grid manager. It's not a raw auction every half hour.
PJM has most of their training materials on line.[1] Those give a sense of how PJM does it. Start with "PJM 101", "Generation Basics", and "How PJM operates and dispatches".
PJM has a day-ahead market, where most of the capacity is booked a day in advance, and a real-time market, where differences from the predicted load are handled. This allows everybody involved to plan ahead a day. There's also "non-economic operation", where, in the event of big problems, the PJM control center just tells generators what to do. That's for emergencies.
All generators post not just a single price, but a price/output curve. Generators also post a "ramp rate"; how fast they can ramp output up or down on request. PJM's job is to optimize all this, which happens on about a five minute cycle. There are also lots of physical constraints - transmission lines and substations can only handle so much power, and policy is to run the system so that any single failure won't take it down. After a failure, the transmission system is reconfigured to become single-point failure tolerant again. There's a control room in Valley Forge, PA, (and a backup control room somewhere else) where about ten people control the wholesale power grid.
California had, briefly, a system with an spot power auction every half hour, with dealers who weren't generators or power consumers, but that was abused and produced blackouts, along with the bankruptcy of PG&E. California now has a day-ahead market and a spot market for fine tuning, like PJM, which resulted in much saner operation. So does ERCOT, the Texas grid manager. It's not a raw auction every half hour.
[1] http://www.pjm.com/training/course-catalog.aspx