Ancillary-Service Clearing Prices

CAISO ancillary-service market clearing prices by delivery hour, market run, region, and product.

Ancillary Services data CAISO market

Query with the agent

Native record

ancillary-service region x product x delivery hour

hourly publication cadence

Evidence

Cleared day-ahead market

A market outcome, not a physical observation

Time basis

Point-in-time records

UTC · event_time

Overview

Despite the legacy column name mw_or_price, values in this table are prices in USD/MWh; zero is a valid clearing price.

Query contract

Preserve one canonical row per (event_time, market_run, anc_region, anc_type) before aggregating.

Analysis rules

Group only after preserving the declared grain: event_time, market_run, anc_region, anc_type.

Interpretation

mw_or_price is a legacy column name; values in this table are clearing prices, and zero is a valid price.

Access

Query from your own tools

Use the guarded HTTP endpoint directly, or connect an MCP client and load the dataset contract with describe_data before calling query_data.

CAISO MCP API reference

HTTP endpoint

POST /api/v1/datasets/caiso_as_prices/query

Schema6

Column

Type

event_timeDateTime64(6, 'UTC')

market_runLowCardinality(String)

anc_regionLowCardinality(String)

anc_typeLowCardinality(String)

mw_or_priceNullable(Float64)

ingested_atDateTime64(6, 'UTC')

Sample data

event_time	market_run	anc_region	anc_type	mw_or_price	ingested_at
2026-09-04 06:00:00.000000	dam	AS_SP26_EXP	SR	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_SP26_EXP	RU	0.2755	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_SP26_EXP	RD	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_SP26_EXP	NR	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_SP26	SR	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_SP26	RU	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_SP26	RD	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_SP26	NR	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_NP26_EXP	SR	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_NP26_EXP	RU	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_NP26_EXP	RD	0.64071	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_NP26_EXP	NR	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_NP26	SR	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_NP26	RU	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_NP26	RD	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_NP26	NR	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_CAISO_EXP	SR	1	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_CAISO_EXP	RU	5	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_CAISO_EXP	RMU	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_CAISO_EXP	RMD	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_CAISO_EXP	RD	2.1	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_CAISO_EXP	NR	1	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_CAISO	SR	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_CAISO	RU	0	2026-09-03 17:16:31.892046
2026-09-04 06:00:00.000000	dam	AS_CAISO	RD	0	2026-09-03 17:16:31.892046

Coverage

85.6% complete613 gap days3,653 days with data

Show coverage history ▾

Coverage: 85.6%Days with data: 3,653Gaps: 613

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Related ancillary services data

Related ancillary services data
Dataset	Description
Ancillary-Service ProcurementCAISO · hourly	CAISO ancillary-service procurement quantities by delivery hour, market run, region, product, and result type.
CAISO Day-Ahead Ancillary PricesCAISO · hourly (day-ahead)	Cleared day-ahead ancillary-service capacity prices in CAISO, one row per hour, AS region and product. 2,172,326 rows, 2014-12 to now. Products: reg_up, reg_down, spin, non_spin, reg_mileage_up, reg_mileage_down. 12 CAISO ancillary-service regions (AS_CAISO, AS_NP26, AS_SP26 and their expanded variants). The expanded regions overlap the base ones by design — never sum across regions. price_usd_mw is a price for CAPACITY held in reserve — dollars per megawatt of commitment — not dollars per megawatt-hour of energy delivered. The two are different units and are not comparable to an LMP.
Ancillary Service Market Clearing PricesSPP · 5-minute (RTBM) and hourly (Day-Ahead)	Cleared ancillary-service prices by SPP reserve zone for both the real-time balancing market and the day-ahead market. SPP's product set does not map onto other ISOs': regulation clears as a separate service (capacity) price and mileage price in each direction (reg_up_service, reg_up_mile, reg_dn_service, reg_dn_mile), alongside ramp up and down, spinning, supplemental, and uncertainty products. IMPORTANT: reserve_zone mixes two grains. It carries the numeric ancillary reserve zones (1 through 5 under the SPP balancing authority, 21 under the separate SWPW balancing authority) AND the two balancing-authority roll-ups, 'SPP' and 'SWPW', whose prices equal those of their member zones. Aggregating across every value of reserve_zone double-counts the market.
Ancillary Service PricesERCOT · hourly (DAM)	Hourly market clearing prices for the ancillary services ERCOT procures alongside energy in its Day-Ahead Market, broken out by product: Regulation Up (RegUp), Regulation Down (RegDown), Responsive Reserve (RRS), Non-Spinning Reserve (NSPIN), and the ERCOT Contingency Reserve Service (ECRS). These prices represent what the grid pays per megawatt to hold capacity in reserve for frequency control and contingency response, separate from the energy itself. Watching them shows when reserves are scarce and expensive (often during tight or volatile conditions), which informs how generators and storage operators allocate capacity between energy and reserve markets, and gives researchers a read on the cost of keeping the Texas grid reliable. ECRS, added in 2023, is the newest of these products and has at times cleared at notably high levels.