Mexican wholesale electricity market
PML: energy, congestion and losses explained
The Local Marginal Price (Precio Marginal Local, PML) is the price CENACE publishes for a pricing node and operating hour. Its three signed components explain why prices differ by place and time.
PML = Energy + Congestion + Losses
Energy
The energy component of the marginal price. Use it as a reference for understanding the location-specific adjustments.
Congestion
The price adjustment associated with transmission constraints. It can raise or lower the nodal price; its sign matters.
Losses
The marginal price adjustment associated with electrical losses. A negative value reduces PML; it is not a negative physical energy loss.
Read the signed contribution
Illustrative example, not a market observation: energy 1,000 + congestion −200 + losses 50 = PML 850 MXN/MWh. Congestion lowers the price by 200 while losses add 50. A 100% share chart would obscure these negative contributions and becomes unstable near a zero total.
MDA / MTR
MDA is the day-ahead market; MTR is the real-time market. Compare the same node, dates and operating hours. A difference between unmatched samples is not a like-for-like market spread.
Source: CENACE · Aggregation methodology.