California, United States.
Wholesale design: nodal energy, ancillary-service, and day-ahead flexibility market with a multi-BAA Extended Day-Ahead Market, embedded in a state-led bilateral resource-adequacy framework.
Energy in CAISO trades in 3 layers: Day-Ahead Market, Extended Day-Ahead Market and Real-Time Market. Participation in Real-Time Market is mandatory. Scheduling and settlement, where the cited sources give them, are in the table below.
| Layer | Scheduling | Settlement |
|---|---|---|
| Day-Ahead Market | hourly awards with fifteen-minute granularity introduced through market enhancements where applicable | locational marginal pricing for energy and ancillary-service marginal prices |
| Extended Day-Ahead Market | multi-balancing-authority-area day-ahead optimization with hourly energy and reliability-capacity awards and day-ahead procurement of fifteen-minute-dispatchable imbalance reserves | locational marginal pricing for energy and product-specific marginal prices for imbalance reserve and reliability capacity |
| Real-Time Market (mandatory) | fifteen-minute market and five-minute real-time dispatch | locational marginal pricing for energy and ancillary-service marginal prices |
CAISO has 10 ancillary-service products, across 5 families — regulation, contingency reserve, ramping reserve, reactive power & voltage and black start & restoration: Black Start, Imbalance Reserve Down, Imbalance Reserve Up, Non-Spinning Reserve, Reliability Capacity Down, Reliability Capacity Up, Regulation Down, Regulation Up, and 2 more. Response timing, direction and eligibility for each are in the table below; a product's full record lists the official sources behind it.
Every value below comes from the official sources listed in that product's full record. Most products cite more than one, and the published sources do not say which of them states each individual value, so the binding is to the product's record rather than to a single document. A missing line means the source does not state that value — never that the value is zero.
Scroll the table sideways for the rest of the columns →
| Service | How it activates | Response | Sustained delivery | Procurement |
|---|---|---|---|---|
| Regulation | ||||
| Regulation Down | Response type pre-contingency continuous Trigger continuous regulation range around the resource operating point Dispatched by automatic generation control; control signals are typically issued about every four seconds | No deadline established Certification and ramp capability determine the awarded regulation range; the operator sources reviewed do not support one universal full-response duration for every resource. | As the source describes it The tariff requires regulation capacity to be continuously dispatchable for at least sixty minutes in the Day-Ahead Market and at least thirty minutes in the Real-Time Market; one universal duration would be misleading. | Through day-ahead; real-time Pricing design capacity and mileage components under CAISO regulation settlement rules |
Full record for Regulation Down — document bound, page for these figures not recorded What it is for Follow automatic control signals to correct downward area-control error and frequency deviations. What the source does not state The source states a delivery duration in its own words. It does not state a response time, and the volume is either set per auction or not published as a standing figure — the source does not say which. | ||||
| Regulation Up | Response type pre-contingency continuous Trigger continuous regulation range around the resource operating point Dispatched by automatic generation control; control signals are typically issued about every four seconds | No deadline established Certification and ramp capability determine the awarded regulation range; the operator sources reviewed do not support one universal full-response duration for every resource. | As the source describes it The tariff requires regulation capacity to be continuously dispatchable for at least sixty minutes in the Day-Ahead Market and at least thirty minutes in the Real-Time Market; one universal duration would be misleading. | Through day-ahead; real-time Pricing design capacity and mileage components under CAISO regulation settlement rules |
Full record for Regulation Up — document bound, page for these figures not recorded What it is for Follow automatic control signals to correct upward area-control error and frequency deviations. What the source does not state The source states a delivery duration in its own words. It does not state a response time, and the volume is either set per auction or not published as a standing figure — the source does not say which. | ||||
| Contingency reserve | ||||
| Non-Spinning Reserve | Response type post-contingency Trigger qualified non-synchronized capability that can be synchronized and reach the award within ten minutes Dispatched by CAISO dispatch instruction; resource begins responding within one minute | Expected within 10 min | Minimum obligation at least 30 min | Through day-ahead; real-time Pricing design ancillary-service marginal price |
Full record for Non-Spinning Reserve — document bound, page for these figures not recorded What it is for Provide offline or otherwise non-synchronized contingency reserve after a qualifying disturbance. Checkpoint recap Expected within 10 min · Minimum sustained 30 min What the source does not state The source states the response deadline and a minimum delivery period. It does not state a maximum duration, and the volume is either set per auction or not published as a standing figure — the source does not say which. | ||||
| Reliability Capacity Down RCD | Response type pre-contingency reliability commitment Trigger downward difference between the integrated forward-market schedule and the residual-unit-commitment reliability requirement Dispatched by awarded hourly in residual unit commitment and available for dispatch through the Fifteen-Minute Market | No deadline established Awards are limited by a resource's sixty-minute ramp capability. That is a capability basis, not a real-time activation deadline. | Through day-ahead residual unit commitment Pricing design market-cleared Reliability Capacity Down price in residual unit commitment | |
Full record for Reliability Capacity Down — document bound, page for these figures not recorded What it is for Procure downward capacity in residual unit commitment to manage potential oversupply when the day-ahead energy schedule is above the operator's forecast requirement. Notes from the source RCD is an operational day-ahead reliability product. It is not California Resource Adequacy capacity and is not a long-term capacity auction. What the source does not state It does not state a response time or how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which. | ||||
| Reliability Capacity Up RCU | Response type pre-contingency reliability commitment Trigger upward difference between the integrated forward-market schedule and the residual-unit-commitment reliability requirement Dispatched by awarded hourly in residual unit commitment and available for dispatch through the Fifteen-Minute Market | No deadline established Awards are limited by a resource's sixty-minute ramp capability. That is a capability basis, not a real-time activation deadline. | Through day-ahead residual unit commitment Pricing design market-cleared Reliability Capacity Up price in residual unit commitment | |
Full record for Reliability Capacity Up — document bound, page for these figures not recorded What it is for Procure upward capacity in residual unit commitment so resources remain available when the day-ahead energy schedule is below the operator's forecast requirement. Notes from the source RCU is an operational day-ahead reliability product. It is not California Resource Adequacy capacity and is not a long-term capacity auction. What the source does not state It does not state a response time or how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which. | ||||
| Spinning Reserve | Response type post-contingency Trigger synchronized unloaded capability available to restore supply-demand balance following a contingency Dispatched by CAISO dispatch instruction; resource begins responding within one minute | Expected within 10 min | Minimum obligation at least 30 min | Through day-ahead; real-time Pricing design ancillary-service marginal price |
Full record for Spinning Reserve — document bound, page for these figures not recorded What it is for Provide synchronized contingency reserve after a qualifying disturbance. Checkpoint recap Expected within 10 min · Minimum sustained 30 min What the source does not state The source states the response deadline and a minimum delivery period. It does not state a maximum duration, and the volume is either set per auction or not published as a standing figure — the source does not say which. | ||||
| Ramping reserve | ||||
| Imbalance Reserve Down IRD | Response type pre-contingency flexibility Trigger downward uncertainty between the day-ahead and real-time markets; resources must be dispatchable in the Fifteen-Minute Market Dispatched by A day-ahead award creates a real-time must-offer obligation; awarded capability is available to the Fifteen-Minute Market. | No deadline established Awards are limited by a resource's thirty-minute ramping capability. That capability horizon is not recorded here as a universal activation deadline. | Through integrated forward market Pricing design locational marginal price for Imbalance Reserve Down | |
Full record for Imbalance Reserve Down — document bound, page for these figures not recorded What it is for Reserve downward flexible ramp capability in the day-ahead market for uncertainty and variability between day-ahead schedules and real-time net load. What the source does not state It does not state a response time or how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which. | ||||
| Imbalance Reserve Up IRU | Response type pre-contingency flexibility Trigger upward uncertainty between the day-ahead and real-time markets; resources must be dispatchable in the Fifteen-Minute Market Dispatched by A day-ahead award creates a real-time must-offer obligation; awarded capability is available to the Fifteen-Minute Market. | No deadline established Awards are limited by a resource's thirty-minute ramping capability. That capability horizon is not recorded here as a universal activation deadline. | Through integrated forward market Pricing design locational marginal price for Imbalance Reserve Up | |
Full record for Imbalance Reserve Up — document bound, page for these figures not recorded What it is for Reserve upward flexible ramp capability in the day-ahead market for uncertainty and variability between day-ahead schedules and real-time net load. What the source does not state It does not state a response time or how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which. | ||||
| Reactive power & voltage | ||||
| Voltage Support | Response type continuous or directed Trigger facility-specific voltage schedule and reactive capability Dispatched by automatic voltage control or CAISO instruction | Expected within 60 s | Through tariff-based or contractual Pricing design tariff-based compensation rather than a uniform co-optimized reserve price | |
Full record for Voltage Support — document bound, page for these figures not recorded What it is for Maintain transmission-system voltage and reactive-power needs. Checkpoint recap Expected within 60 s What the source does not state The source states the response deadline. It does not state how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which. | ||||
| Black start & restoration | ||||
| Black Start | Response type restoration Trigger system restoration following a blackout or widespread outage Dispatched by CAISO restoration instruction and approved restoration plan | Through contractual Pricing design contract or tariff compensation | ||
Full record for Black Start — document bound, page for these figures not recorded What it is for Start without external station power and support system restoration. What the source does not state It does not state a response time or how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which. | ||||
No central capacity market. CAISO has 1 capacity/adequacy arrangement — California Resource Adequacy program — and it works differently.
State and local regulatory authorities establish obligations; load-serving entities contract bilaterally and make showings to CAISO. CAISO's Capacity Procurement Mechanism is a backstop designation process, not a routine centralized capacity auction.
Current as of · from the Global Electricity Market Catalogue v1.2.0 (compiled to , CC BY 4.0, rendered here with wording edited for readability). Facts belong to the linked official authorities; verify the current rules before design or bidding decisions.
The markets index holds the full set. For what the grid demands of a battery here, see the grid-code ride-through atlas.