IESO Constraint Shadow Prices (day-ahead)

Shadow prices of binding transmission constraints, by IESO's constraint id and name.

Congestion & Constraints data IESO market

Query with the agent

Native record

constraint x interval

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

Shadow prices of binding transmission constraints, by IESO's constraint id and name.

Query contract

Preserve one canonical row per (event_time, constraint_id) before aggregating.

Analysis rules

Rows repeat across polls: dedupe with argMax(value, ingested_at) per key.

Interpretation

event_time marks the END of the interval or hour. IESO delivers on EST all year, but this mirror's event_time was built on Toronto wall time, so between the second Sunday of March and the first Sunday of November it is one hour early. The delivery end is event_time + toIntervalSecond(timeZoneOffset(toTimeZone(event_time, 'America/Toronto')) + 18000); rows in the spring-forward hour cannot be placed. Toronto civil time is for display only.
Prices are Canadian dollars per MWh. Never add, rank or average them with US-dollar prices without a dated exchange rate, and say which rate was used.

Access

Need the full history of this dataset in Snowflake, Databricks or your own storage? Data services delivers it on a schedule.

Schema5

Column

Type

event_timeDateTime64(6, 'UTC')

constraint_idLowCardinality(String)

constraint_nameNullable(String)

shadow_priceNullable(Float64)

ingested_atDateTime64(6, 'UTC')

Sample data

Coverage

No time-indexed data — coverage isn’t applicable to this dataset.

Related congestion & constraints data

Related congestion & constraints data
Dataset	Description
IESO Constraint Shadow Prices (real-time)IESO · five-minute	Shadow prices of binding transmission constraints, by IESO's constraint id and name.
Available & Total Transfer CapabilityNYISO · hourly / 15-minute market-run timesteps	NYISO available transfer capability and total transfer capability by interface and market run. The source rows are melted so DAM and HAM timesteps can be compared by interface over time.
CAISO Day-Ahead Binding ConstraintsCAISO · hourly	Which transmission facilities bound in CAISO's day-ahead market and what each one cost, one row per interval and constraint. 463,496 rows, 2015-01 to now. Columns: event_time, constraint_name, shadow_price_usd_mwh, plus constraint_cause. The shadow price is the marginal cost of the binding limit — what the market would have saved from one more megawatt of capability on that element. This is the table that answers WHY congestion appeared; a price spread between two locations shows that they separated but not which facility separated them.
CAISO Real-Time Binding ConstraintsCAISO · 5-minute	Which transmission facilities bound in CAISO's real-time market and what each one cost, one row per interval and constraint. 6.43M rows, 2015-01 to now. Columns: event_time, constraint_name, shadow_price_usd_mwh, plus constraint_type ('intertie', 4.06M rows, or 'nomogram', 2.36M), direction, and constraint_cause. The shadow price is the marginal cost of the binding limit — what the market would have saved from one more megawatt of capability on that element. This is the table that answers WHY congestion appeared; a price spread between two locations shows that they separated but not which facility separated them.

event_time	constraint_id	constraint_name	shadow_price	ingested_at
2026-10-05 04:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	-7.89	2026-10-10 17:30:17.466939
2026-10-05 04:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	-7.89	2026-10-10 16:30:10.759449
2026-10-05 03:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939
2026-10-05 03:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 16:30:10.759449
2026-10-05 02:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939
2026-10-05 02:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 16:30:10.759449
2026-10-05 01:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939
2026-10-05 01:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 16:30:10.759449
2026-10-05 00:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939
2026-10-05 00:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 16:30:10.759449
2026-10-04 23:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939
2026-10-04 23:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 16:30:10.759449
2026-10-04 22:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939
2026-10-04 22:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 16:30:10.759449
2026-10-04 21:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939
2026-10-04 21:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 16:30:10.759449
2026-10-04 20:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939
2026-10-04 20:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 16:30:10.759449
2026-10-04 19:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939
2026-10-04 19:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 16:30:10.759449
2026-10-04 18:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939
2026-10-04 18:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 16:30:10.759449
2026-10-04 17:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939
2026-10-04 17:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 16:30:10.759449
2026-10-04 16:00:00.000000	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	BASE CASE 0 S-FETT.TAB6_N582L_24K.EQ4_DSO	0	2026-10-10 17:30:17.466939