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Locational marginal price (LMP)

A locational marginal price is the wholesale price of electricity at one point on the grid. It is the cost of serving one more MWh there, given the plants running and the limits of the lines.

Also called LMP, nodal price

Formula

LMP = energy + congestion + losses

Energy
The market-wide cost of the next MWh
Congestion
The extra cost or credit when lines into or out of the location are full
Losses
The cost of power lost on the way. ERCOT prices have no separate loss part.

In the data

$21.75per MWh between the 10th and 90th percentile ERCOT plant node, 2025 average

One market, many prices. In ERCOT the middle 80% of plant nodes averaged $24.08 to $45.83 per MWh in 2025. That was the widest spread of the seven markets.

Average real-time price at plant nodes, 2025, $/MWh
  • 10th to 90th percentile
  • Median node
  1. SPP$22.77
  2. ERCOT$31.77
  3. CAISO$33.78
  4. MISO$36.64
  5. PJM$43.72
  6. NYISO$58.02
  7. ISO-NE$64.83

ISO real-time prices, 2025. One row per plant pricing node with a full year of hours; bars run from the 10th to the 90th percentile.Open the map

Built from InfraMap's 2025 data with the same tools the analyst uses.

Common mistakes

  1. Blaming every price gap on congestion. Energy, congestion and losses all move the price, and a gap alone does not show which line caused it.
  2. Averaging several nodes into one price without saying so. A plant's price is the price at its own node.
  3. Treating a node price as what the plant earned. Contracts, hedges and the timing of output change the money it actually receives.

How the InfraMap analyst defines it

Marginal price of serving electricity at a location given dispatch and network constraints. Energy, congestion and losses can contribute. A spread is not proof of one constraint.

Reviewed October 1, 2026 against the references below. The analyst and the MCP server answer with this definition.

Primary references

See it for any US plant

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