Ask the Grid
Open live grid

Congestion & Constraints

Binding transmission constraints, their shadow prices, and the transfer-capability limits behind them — the datasets that support why prices at two locations separated, not just that they did — plus ERCOT's CRR auction, the cleared instrument for hedging that separation.

25 datasetspublished by ATG DataNYISO6ERCOT4CAISO4SPP4ISONE4MISO2PJM1

Congestion & Constraints datasets
DatasetRows
NYISOAvailable & Total Transfer CapabilityATG Data·NYISO·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.15.4M1999
CAISOCAISO Day-Ahead Binding ConstraintsATG Data·CAISO·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.466.1K2015
CAISOCAISO Real-Time Binding ConstraintsATG Data·CAISO·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.6.5M2015
ERCOTCRR Monthly Auction ResultsATG Data·ERCOT·Cleared ERCOT monthly Congestion Revenue Right auction awards, one row per source-to-sink CRR and time-of-use block, including awarded MW and the auction shadow price per MWh. This is public auction evidence for who acquired a path and at what clearing price. It does not contain realized day-ahead congestion settlements, fees, later trades, the holder's full portfolio, or net profit, so auction cost must not be described as payout or profitability. The official source is ERCOT report NP7-803-M.1.2M2025
SPPDay-Ahead Binding ConstraintsATG Data·SPP·Transmission constraints binding in SPP's day-ahead market, published hourly for the delivery day with the constraint name, shadow price, direction, and the monitored limit and flow in MW. Pairs with the real-time binding-constraint table to compare which constraints the day-ahead market anticipated against those that actually bound in real time. As with the real-time table, no contingency or monitored-facility name is published.1.1M2017
ISO-NEDay-Ahead ConstraintsATG Data·ISONE·ISO-NE day-ahead transmission constraints with constraint, contingency, interface flag, and marginal value. A non-zero marginal value is cleared day-ahead congestion evidence, not proof of a real-time binding condition.24.3K2022
NYISODay-Ahead Limiting ConstraintsATG Data·NYISO·NYISO day-ahead limiting-constraint records for the market-clearing plan, including limiting facility, facility PTID, contingency, and constraint cost. Paired with day-ahead LBMP components, it helps explain expected congestion and transfer limits before real-time operations.1.0M2001
PJMDay-Ahead Transmission ConstraintsATG Data·PJM·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. Note that PJM does not publish a real-time binding-constraint/shadow-price feed, so real-time congestion is read from the congestion component of the LMP tables rather than from a constraints table. Source: PJM Data Miner 2.548.2K2010
ERCOTERCOT Day-Ahead Binding ConstraintsATG Data·ERCOT·Which transmission facilities bound in ERCOT's day-ahead market and what each one cost, one row per interval and constraint. 2.94M rows, 2017-01 to the next delivery day. Columns: event_time, constraint_name, shadow_price_usd_mwh, plus contingency, from_station and to_station, limit_mw and flow_mw. 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.3.0M2017
ERCOTERCOT Real-Time Binding ConstraintsATG Data·ERCOT·Which transmission facilities bound in ERCOT's real-time market and what each one cost, one row per interval and constraint. 8.42M rows, 2014-05 to now. Columns: event_time, constraint_name, shadow_price_usd_mwh, plus contingency (the outage the limit is evaluated against), from_station and to_station (the ends of the constrained element), limit_mw and flow_mw. 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.8.4M2014
MISOHourly Binding Constraint CountATG Data·MISO·MISO's hourly count of real-time binding transmission constraints. It supports system-level congestion frequency analysis, but does not name a facility, contingency, or shadow price and therefore cannot attribute congestion to a specific constraint.56.7K2026
CAISOIntertie Constraint Shadow Prices (5-minute)ATG Data·CAISO·CAISO OASIS 5-minute real-time shadow prices on intertie / scheduling-point constraints, by tie and flow direction. The shadow price is the marginal cost of a binding intertie limit, so this is the direct signal for congestion between CAISO and neighboring balancing areas: a non-zero price means an import/export path is constrained and is shaping locational prices at the border. Traders use it to explain inter-BAA basis and to see which ties are binding and in which direction, and operators use it to track where transfer limits are actively holding back scheduling. History spans 2015 to present at ~99% daily coverage. The official source is CAISO OASIS.7.4M2015
MISOLive Binding ConstraintsATG Data·MISO·Current MISO real-time, sub-regional, and reserve constraints with shadow price and penalty-curve breakpoints. A non-zero price is direct constraint evidence; the feed does not always supply a resolvable monitored facility or contingency.22.2K2026
ISO-NELMP Avg Congestion DAATG Data·ISONE·ISO-NE's published LMP Avg Congestion DA source feed. This catalog page exposes the physical schema, coverage, and latest source rows without inventing a normalized grain for publisher-shaped snapshot fields. Use the documented key and event time when comparing revisions or vintages.85.1K2017
CAISONomogram Shadow Prices (5-minute)ATG Data·CAISO·CAISO OASIS 5-minute real-time interval shadow prices on nomogram constraints. A nomogram is a multi-element stability or transfer limit (a relationship across several branches or interfaces rather than a single line), so a binding nomogram shadow price flags where a security constraint — not just one overloaded line — is driving congestion cost. Useful for understanding structural transmission limits and stability-driven congestion in the CAISO footprint, complementing the single-branch and intertie shadow prices. History spans 2015 to present at ~99% daily coverage. The official source is CAISO OASIS.3.7M2015
NYISONYISO Day-Ahead Binding ConstraintsATG Data·NYISO·Which transmission facilities bound in NYISO's day-ahead market and what each one cost, one row per interval and constraint. 527,082 rows, 2015-01 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.527.6K2015
NYISONYISO Real-Time Binding ConstraintsATG Data·NYISO·Which transmission facilities bound in NYISO's real-time market and what each one cost, one row per interval and constraint. 2.07M rows, 2015-01 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. 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.5.9M2001
NYISOPre-Scheduled ATC/TTCATG Data·NYISO·NYISO long-term pre-scheduled available transfer capability and total transfer capability by interface. Use it for forward interface-capability context rather than live flows.2.3M2004
SPPReal-Time Binding ConstraintsATG Data·SPP·Transmission constraints binding in SPP's real-time balancing market, published every five minutes with the constraint name, its shadow price, the constrained direction, and the monitored limit and actual flow in MW. A non-zero shadow price is direct evidence that the named constraint was binding and pricing congestion in that interval. SPP publishes no associated contingency or monitored-facility name on this feed, so a constraint name cannot be resolved to a physical facility from this table alone.35.5M2017
NYISOReal-Time Limiting ConstraintsATG Data·NYISO·NYISO real-time limiting-constraint records that identify the limiting facility, facility PTID, contingency, and constraint cost shaping dispatch and price separation. Use alongside real-time LBMP components to explain congestion rather than just observing price spreads.6.3M2001
ERCOTSCED Shadow Prices & Binding ConstraintsATG Data·ERCOT·Binding transmission constraint and contingency pairs from ERCOT's Security Constrained Economic Dispatch runs, including the named facilities, limits, flows when published, violations, and shadow prices. A row establishes that the named constraint bound in that SCED interval and its marginal system cost. It does not, by itself, identify which settlement point or hub the constraint affected, measure total substation utilization, or explain every contemporaneous LMP separation; those claims require shift-factor or direct attribution evidence. History spans 2017 to present. The official source is ERCOT report NP6-86-CD.9.6M2014
ISO-NESingle SRC Contingency LimitsATG Data·ISONE·ISO-NE's published Single SRC Contingency Limits source feed. This catalog page exposes the physical schema, coverage, and latest source rows without inventing a normalized grain for publisher-shaped snapshot fields. Use the documented key and event time when comparing revisions or vintages.5.5M2022
SPPSPP Day-Ahead Binding ConstraintsATG Data·SPP·Which transmission facilities bound in SPP's day-ahead market and what each one cost, one row per interval and constraint. 1.11M rows, 2017-01 to the next delivery day. Columns: event_time, constraint_name, shadow_price_usd_mwh, plus direction, limit_mw and flow_mw. 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.1.1M2017
SPPSPP Real-Time Binding ConstraintsATG Data·SPP·Which transmission facilities bound in SPP's real-time market and what each one cost, one row per interval and constraint. 35.41M rows, 2017-01 to now. Columns: event_time, constraint_name, shadow_price_usd_mwh, plus direction, limit_mw and flow_mw. 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.35.5M2017
ISO-NETotal Transfer CapabilityATG Data·ISONE·ISO-NE's published Total Transfer Capability source feed. This catalog page exposes the physical schema, coverage, and latest source rows without inventing a normalized grain for publisher-shaped snapshot fields. Use the documented key and event time when comparing revisions or vintages.40.9K2022