PJM Day-Ahead Binding Constraints

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

Congestion & Constraints data

Download data

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

2.65M rows, 2010-01 to the next delivery day. 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. 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 on event_time; the constraint explains the market-wide congestion pattern, not one location's share of it

Interpretation

This is day-ahead only. PJM's real-time shadow prices are ingested (pjm.rt_marginal_value, pjm.transmission_limits) but no atg.pjm_constraints_rt canonical table has been built off them yet — a real-time PJM congestion answer needs that build, not a new ingest.
A shadow price is the marginal value of relaxing the limit. It is not the amount of power that flowed, not a measure of how loaded the line was, and not a dollar cost anyone paid.

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
2026-09-19 18:00:00.000000	TERMINAL_T1_34512_XF	ACTUAL	-27.85
2026-09-19 18:00:00.000000	Five Points - BrandyWine 138kV l/o Prescott BK1 345/69kV	Prescott BK1 345/69kV	-251.26
2026-09-19 18:00:00.000000	MIAMIFOR_138KVMIA-08G1_1_LN	L345.TannersCreek-MiamiFort	-216.77
2026-09-19 18:00:00.000000	COLLEGEC_138KVCOL-COL6_1_LN	L345.TannersCreek-MiamiFort	-168.63
2026-09-19 18:00:00.000000	NOTTINGH_NOT2301-3_1_LN	L500.Conastone-PeachBottom.5012	-201.85
2026-09-19 18:00:00.000000	Lallendorf - Fostoria 345kV l/o Lemoyne - Majestic 345kV	L345.Lemoyne-Majestic	-53.78
2026-09-19 18:00:00.000000	Kokomo - Tipton W. 230kV l/o Nucor - Cayuga 345kV	Nucor-Cayuga 345 kV	-324.89
2026-09-19 18:00:00.000000	ELIMSPOR_230KVELI-SUN_1_LN	L230.Montour-Saegers.1	-11.51
2026-09-19 18:00:00.000000	EDWSFERY_230KV23111_1_LN	L500.Doubs-GooseCreek.514	-33.64
2026-09-19 18:00:00.000000	CONASTON_230KVCNS-OTT_1_LN	L500.Conastone-PeachBottom.5012	-165.03
2026-09-19 18:00:00.000000	EASTON-EMUNI 6772 A 69 KV	L69.Easton-EastonTap-Muni-Longwood-WyeMills.6707	-48.15
2026-09-19 18:00:00.000000	KAMMER2_138KVKAM-NAT_1_LN	ACTUAL	-404.33
2026-09-19 18:00:00.000000	GILBERT_115KVGIL-GLEN_1_LN	L230.MartinsCreek-Portland.1008	-49.36
2026-09-19 17:00:00.000000	NOTTINGH_230KVNOT-PEA_1_LN	L500.Conastone-PeachBottom.5012	-178.35
2026-09-19 17:00:00.000000	Lake George - Tower Road 138 kV l/o Lake George - Babcock 345 kV	L345.Babcock-LakeGeorge (NIPS)	-17.04
2026-09-19 17:00:00.000000	Monroe-Lallendorf 345 kV l/o Lemoyne-Majestic 345 kV	L345.Lemoyne-Majestic	-17.47
2026-09-19 17:00:00.000000	MIAMIFOR_138KVMIA-08G1_1_LN	L345.TannersCreek-MiamiFort	-223.16
2026-09-19 17:00:00.000000	ELIMSPOR_230KVELI-SUN_1_LN	L230.Montour-Saegers.1	-10.47
2026-09-19 17:00:00.000000	Kokomo - Tipton W. 230kV l/o Nucor - Cayuga 345kV	Nucor-Cayuga 345 kV	-232.98
2026-09-19 17:00:00.000000	Five Points - BrandyWine 138kV l/o Prescott BK1 345/69kV	Prescott BK1 345/69kV	-142.71
2026-09-19 17:00:00.000000	EASTON-EMUNI 6772 A 69 KV	L69.Easton-EastonTap-Muni-Longwood-WyeMills.6707	-80.7
2026-09-19 17:00:00.000000	EDWSFERY_230KV23111_1_LN	L500.Doubs-GooseCreek.514	-37.63
2026-09-19 17:00:00.000000	KAMMER2_138KVKAM-NAT_1_LN	ACTUAL	-45.12
2026-09-19 17:00:00.000000	CONASTON_230KVCNS-OTT_1_LN	L500.Conastone-PeachBottom.5012	-153.83
2026-09-19 17:00:00.000000	Dearborn - Pierce 345 kV l/o Tanners Creek - Miami Fort 345 kV	L345.TannersCreek-MiamiFort	-58.92

Coverage

100.0% complete0 gap days6,106 days with data

Show coverage history

Coverage: 100.0%Days with data: 6,106Gaps: 0

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Related congestion & constraints data

Related congestion & constraints data
Dataset	Description
Constraint Shift Factor RunsPJM · nightly (one row per completed run)	One row per COMPLETED nightly estimation of PJM constraint shift factors, and the only record that a run finished. Resolve the latest usable run here — computed_at = (SELECT max(computed_at) FROM atg.pjm_constraint_sensitivity_runs) — and never off max(computed_at) of the sensitivities themselves, because a run writes its rows in blocks that all carry the new timestamp and an unfinished or abandoned run would otherwise look like the newest one. Each row also carries how much evidence that run had: interval_coverage is the fraction of published dispatch intervals that survived admission, intervals_refused_unexplained counts intervals showing congestion with no constraint recorded as binding (an unobserved binding set), constraint_feed_lag_minutes is how far the constraint feed trailed the price feed, and constraints_seen / constraints_in_fit / constraints_reported show how many constraints bound, how many were good enough to control for, and how many earned a published estimate.
Constraint Shift Factors (Estimated)PJM · nightly (60-day rolling estimation window)	Estimated sensitivity of every PJM pricing location's price to every binding transmission constraint: one row per constraint, contingency, and location, recomputed nightly over a rolling 60-day window. This is what answers 'which nodes drive this constraint' and 'which constraints is this node exposed to'. THE DAY-AHEAD MARKET, not real time: this estimate is fitted to day-ahead marginal values against day-ahead nodal congestion and it describes day-ahead congestion. It covers PJM's day-ahead binding constraints with their contingency over roughly 14,450 pricing nodes. PJM names no terminals, so from_station and to_station are always empty. PJM's real-time shadow prices ARE ingested now (pjm_rt_marginal_value, pjm_transmission_limits) but no estimate has been fitted to them and no atg.pjm_constraints_rt canonical table exists yet — a real-time PJM answer needs that fitting work, not a new ingest. shift_factor is in the ISO's orientation — POSITIVE means an incremental MW injected at that node increases loading on the constraint and the node is paid below system lambda while it binds; NEGATIVE means generation there relieves the constraint and earns a premium. These are ESTIMATES recovered from the price identity LMP = energy - sum(shift_factor x shadow_price), not a published PTDF matrix. They are measured RELATIVE TO THE MARKET'S REFERENCE — the identity yields SF(node) - SF(reference), so a single absolute value should be quoted as 'relative to the system reference' rather than as the node's PTDF, while DIFFERENCES between nodes are exact because the reference term cancels. Three further differences from a published matrix: they describe a NODE (a generator at that node inherits its location's value, and two units at one node are indistinguishable), they reflect the topology actually in effect across the window including outages rather than a stated base case, and every one carries a std_error from a 200-draw block bootstrap that resamples whole days. Read std_error before quoting shift_factor: an estimate whose absolute value is not at least twice its standard error is not distinguishable from zero. estimation_status says why a row has no number — 'thin_support' (in the fit, so it is controlled for, but under 12 binding intervals or under 3 distinct binding days), 'no_support' (under 3 binding intervals; not a regressor), or 'collinear' (it bound in lockstep with another constraint, so the two cannot be separated). Where from_station and to_station are populated they identify the monitored element and are NOT the constrained direction — the sign of shift_factor is what says which way. Every read must pin computed_at to one run, and must resolve that run through the companion atg.<iso>_constraint_sensitivity_runs ledger rather than off max(computed_at) here — rows are written in blocks that all carry the new timestamp, so an unfinished or abandoned run would otherwise look like the newest. Mixing runs averages a node across different network topologies.
Day-Ahead Constraint Marginal ValuesPJM · hourly (day-ahead)	What each binding day-ahead transmission constraint cost in PJM, hour by hour: the monitored facility, the contingency facility, and the constraint's marginal value — its shadow price, the saving from one more MW of headroom. This is the table that says how hard a constraint bound, where pjm_da_transconstraints says only that it did. PJM PUBLISHES THIS VALUE AS A NEGATIVE NUMBER: 2,654,985 negative rows against 43 positive over the table's full history, which reaches back to 2010. Read its magnitude as the cost of the constraint and do not compare its sign against another market's. This answers day-ahead congestion only; for real-time, see pjm_transmission_limits and pjm_rt_marginal_value. Source: PJM Market Data.
Day-Ahead Transmission ConstraintsPJM · daily (day-ahead)	The transmission constraints that bound in PJM's day-ahead market: the monitored facility, the contingency facility, the duration, and the congestion event. It names which elements are expected to limit flows for the next operating day. What it does not carry is what the constraint COST: the marginal value is published separately, in pjm_da_marginal_value. For real-time binding constraints, see pjm_transmission_limits (the live tip, ~9 minutes behind) and pjm_rt_marginal_value (the settled record, ~20 hours behind). Source: PJM Market Data.