ISO-NE Day-Ahead Binding Constraints

Which transmission facilities bound in ISO-NE's day-ahead market and what each one cost, one row per interval and constraint.

Congestion & Constraints data ISO-NE market

Query with the agent

Native record

constraint x delivery hour

hourly publication cadence

Evidence

Cleared day-ahead market

A market outcome, not a physical observation

Time basis

Interval-start records

UTC · event_time

Overview

24,146 rows, 2022-01 to now. Columns: event_time, constraint_name, shadow_price_usd_mwh, plus contingency. 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. ISO-NE's negative source marginal values are sign-normalized here so larger positive values have the same meaning as the other markets. 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.

Query contract

A row means this constraint was binding in this interval. Absence of a row means it was not binding, not that it does not exist.

Analysis rules

Rank constraints by summed or averaged shadow price over a window, and say which — a constraint that binds rarely but hard ranks differently from one that binds constantly and cheaply.
Count binding INTERVALS, not rows, when describing how often a constraint bound.

Related analysis

explaining why a location's congestion component moved in an interval · align event_time to iso_ne.lmp rows filtered to market_run='da_hourly_final' and scope='all'; the constraint explains the market-wide congestion pattern, not one location's share of it

Interpretation

shadow_price_usd_mwh is sign-normalized: ISO-NE's source marginal_value is negated because the source publishes a binding marginal value as negative in more than 99.9% of rows. In this canonical table, a larger positive value consistently means a more expensive binding constraint.
The handful of positive source marginal values become negative canonical shadow prices and remain present. They are preserved anomalies, not clipped or silently discarded.

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.

ISO-NE MCP API reference

HTTP endpoint

POST /api/v1/datasets/isone_canonical_constraints_da/query

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

Schema4

Column

Type

event_timeDateTime64(6, 'UTC')

constraint_nameLowCardinality(String)

contingencyLowCardinality(String)

shadow_price_usd_mwhNullable(Float64)

Sample data

event_time	constraint_name	contingency	shadow_price_usd_mwh
2026-10-17 02:00:00.000000	Node_Shoreham_Export	Generic Constraint	0.53
2026-10-17 02:00:00.000000	S_NAUGTK1580ALN	STEV1232	2.02
2026-10-17 02:00:00.000000	RUM-EX	Interface	7.01
2026-10-17 02:00:00.000000	VNRDW	Interface	42.23
2026-10-17 01:00:00.000000	Node_Shoreham_Export	Generic Constraint	5.16
2026-10-17 01:00:00.000000	RUMFIP	Interface	4.4
2026-10-17 01:00:00.000000	VNRDW	Interface	39.18
2026-10-17 00:00:00.000000	RUMFIP	Interface	10.78
2026-10-17 00:00:00.000000	VNRDW	Interface	43.78
2026-10-16 23:00:00.000000	RUMFIP	Interface	20.97
2026-10-16 23:00:00.000000	JOHNST_TT172S-3ALN	S171	16.29
2026-10-16 23:00:00.000000	VNRDW	Interface	54.49
2026-10-16 22:00:00.000000	JOHNST_TT172S-3ALN	S171	25.23
2026-10-16 22:00:00.000000	RUMFIP	Interface	29.27
2026-10-16 22:00:00.000000	S_NAUGTK1580ALN	STEV1232	143.1
2026-10-16 22:00:00.000000	BAKER_ST110-511-4ALN	Actual	0.02
2026-10-16 22:00:00.000000	VNRDW	Interface	63.51
2026-10-16 22:00:00.000000	BAKER_ST110C110CXF	Actual	0.02
2026-10-16 21:00:00.000000	WYM-EX STAB	Generic Constraint	43.76
2026-10-16 21:00:00.000000	RUMFIP	Interface	21.96
2026-10-16 21:00:00.000000	BAKER_ST110-510-4ALN	Actual	0.01
2026-10-16 21:00:00.000000	JOHNST_TT172S-3ALN	S171	19.85
2026-10-16 21:00:00.000000	BAKER_ST110D110DXF	Actual	0.01
2026-10-16 21:00:00.000000	S_NAUGTK1580ALN	STEV1232	101.75
2026-10-16 21:00:00.000000	VNRDW	Interface	58.06

Coverage

94.9% complete89 gap days1,662 days with data

Show coverage history

Coverage: 94.9%Days with data: 1,662Gaps: 89

2026

2025

2024

2023

2022

gaplessmore

Related congestion & constraints data

Related congestion & constraints data
Dataset	Description
Day-Ahead ConstraintsISONE · daily hourly market results	ISO-NE day-ahead transmission constraints with constraint, contingency, interface flag, and the publisher-signed marginal_value. The source values use the opposite sign from Ask the Grid's canonical shadow price, so analytical ranking should use atg.isone_constraints_da; a non-zero value is cleared day-ahead congestion evidence, not proof of a real-time binding condition.
Fifteen-minute final constraintsISONE · day publication	ISONE's Fifteen-minute final constraints. Each row preserves a publisher record, workbook row, or report document with its source member and row index. Source timestamps, units, geographic scope, and revision qualifiers are retained in record_json; event_time is collection time; completed_at is when the entire document became available.
Fifteen-minute preliminary constraintsISONE · day publication	ISONE's Fifteen-minute preliminary constraints. Each row preserves a publisher record, workbook row, or report document with its source member and row index. Source timestamps, units, geographic scope, and revision qualifiers are retained in record_json; event_time is collection time; completed_at is when the entire document became available.
Five-minute final constraintsISONE · day publication	ISONE's Five-minute final constraints. Each row preserves a publisher record, workbook row, or report document with its source member and row index. Source timestamps, units, geographic scope, and revision qualifiers are retained in record_json; event_time is collection time; completed_at is when the entire document became available.