What is CAISO
The California Independent System Operator runs the state's power grid and its wholesale electricity markets, from every generator dispatched to the five-minute prices load settles against, for about four in five Californians and a sliver of Nevada.
One grid, three hubs
Wholesale prices reference three trading hubs: NP15 in the north around the Bay Area, SP15 in the south around Los Angeles, and ZP26 in the central valley between them. Prices differ because the wires congest along Path 15 and Path 26, the north-south corridors. Hydro and imports move the north, gas and solar move the south, so a hot afternoon can split the two ends by tens of dollars. Live hub prices show it as it happens.
The duck curve
California builds more solar than anywhere in the country, and it shows in the shape of the day. Midday, solar floods the grid and net load (demand minus wind and solar) sinks into a belly. Then the sun sets while demand holds, and the grid ramps hard through the evening, tens of gigawatts in a few hours. The curve of that day looks like a duck, and batteries now discharge into its neck. Watch the duck curve live.
No coincident peak
Unlike Texas or PJM, California does not bill transmission on a coincident peak. Its access charge is volumetric, a flat rate on every megawatt-hour, and resource adequacy is a wholesale obligation on utilities, not a demand tag on your meter. So there is no single hour to chase and no daily call here. What we publish is the grid itself, live and honest.
Flex Alerts
On the hottest evenings, when the ramp is steep and reserves run thin, CAISO asks the public to conserve from 4 to 9 PM. That call is a Flex Alert. Is there a Flex Alert today tracks the grid's live conditions and points to CAISO's official word.
Watching it live
CAISO publishes its data openly: five-minute load and prices, the fuel mix, hourly forecasts. The live CAISO dashboard shows load against the grid's own forecast, prices at the three hubs, and generation by fuel, with day-ahead vs real-time alongside. No login, no cost.