Grid congestion and curtailmentas of 1 OctCongestion is market-observable: when IEX bid areas clear at different prices, the corridor between them is constrained.

Methodology & caveats

• Market signal, not metered flow. Congestion is inferred from IEX day-ahead bid-area price separation. POSOCO does not publish per-corridor MW, so we never claim a causal corridor flow — this is a price discriminator.
• Regions from areas. IEX areas group by first letter: N→Northern, W→Western, S→Southern, E→Eastern, A→North-Eastern. Each region’s price is the mean of its areas; the national reference is the cross-region median (robust to a single capped area).
• Stress index. A 0-100 blend of market exposure (45%), interchange deviation (35%) and curtailment (20%), renormalized over whichever components have data, with per-state confidence.
• Curtailment coverage is exactly what was reported. State and pooling-station figures come from Grid-India’s daily VRE report and Rajasthan’s SLDC register. The coverage table lists every state with the first and last day held; no other state or date is covered, and absence of a row is not proof of zero curtailment.
• Interchange stress uses scheduled-vs-actual state drawal; the state board snaps to the latest day with broad (≥20-state) coverage.

Congestion is inferred from IEX bid-area price separation — a market signal, not a metered corridor flow (POSOCO does not publish per-corridor MW). Curtailment is as officially reported (NLDC daily VRE report, state SLDC registers); the curtailment endpoint states its coverage.

Frequently asked

What is grid congestion in India's power market?

Grid congestion happens when a transmission corridor can't carry all the power the market wants to move across it. On the IEX day-ahead market it shows up as price separation: when two bid areas clear at different prices in a 15-minute block, the corridor between them is binding. India mostly clears at a single national price, so congestion is episodic rather than constant.

How is congestion measured here?

From IEX bid-area clearing prices. India's areas group into five regional grids (N→Northern, W→Western, S→Southern, E→Eastern, A→North-Eastern). For each 15-minute block we compare each region's price to the cross-region median; a corridor is 'binding' when the two regions differ by more than ₹100/MWh. This is a market signal, not a metered corridor flow — POSOCO does not publish per-corridor MW, so we never claim a causal flow.

What is the congestion stress index?

A transparent 0-100 per-state score that blends three signals: market price-separation exposure (how far the state's region priced away from national), physical interchange deviation (how far actual inter-state drawal drifted from schedule), and reported renewable curtailment. Only components with data contribute — their weights are renormalized over what's present, and every state carries a coverage and confidence breakdown.

What is renewable curtailment and where does it happen?

Curtailment is renewable generation the grid asks to switch off — usually because a transmission corridor is overloaded or the local grid can't absorb the midday solar. In India it concentrates in high-RE states: Rajasthan leads (Bhadla-area 765kV export constraints), followed by Gujarat, and with recorded events in Maharashtra, Andhra Pradesh, Tamil Nadu and Uttar Pradesh. State-wise figures are as officially reported, by Grid-India's daily VRE report and Rajasthan's SLDC register. The coverage table on this page lists every state with the first and last day held.

Which corridor is most often congested?

Historically the Northern–Western (NR-WR) corridor is the most frequent binding constraint, with the Northern region typically the import-constrained (premium) side during high-demand episodes. The Northern–Southern link also binds when southern surplus can't reach the north.

Where can I get the data?

The national, corridor, state and curtailment series are available via the India Energy Atlas API at /api/v1/congestion/*. Congestion updates daily; curtailment updates when an official source publishes, and the curtailment response carries its exact coverage. The page and API are open for reference use.