Entry · Models
DECOMP
Which model estimates the operating cost of each week?
Acronyms: CMO, Marginal Operating Cost; ONS, National Electric System Operator; CCEE, Electric Energy Trading Chamber; PLD, Settlement Price for Differences (spot price).
In one sentence
Model that estimates the CMO published by the ONS for each operating week, by subsystem and load level.
Real example
For the operating week identified by the ONS with the date Oct 2, 2026, the CMO published for the Southeast/Center-West was R$ 42.43/MWh (load levels light R$ 38.72, medium R$ 44.44 and heavy R$ 46.32)Nature of the data: Observed.
No Check this number record of its own in this example: the number comes from the panel's published database, which carries the source and the reference date.
Observed: Value published directly by the official or primary source.
Why it matters
How it is measured
Computer model; its output published by the ONS is the weekly CMO by subsystem and load level.
Not to be confused with
Both estimate the CMO published by the ONS: DECOMP by operating week, subsystem and load level; DESSEM by half hour and by bus.
Both are cited by the CCEE in calculating the PLD. DECOMP has output published by the ONS and used here (the weekly CMO); the technical description of NEWAVE was not checked, and the observatory does not publish its output.
Related entries
In the learning paths
See in the panel
Official source
ONSOpen data portal, dataset “CMO Semanal” (description and data dictionary)
Literal excerpt from the document
Portuguese only“Valores do custo, por unidade de energia produzida, para atender ao incremento de uma unidade de carga no SIN, chamado de Custo Marginal de Operação – CMO. Valores para cada semana operativa por subsistema, e por patamar de carga, além da média semanal, estimados pelo modelo Decomp.”
In other words: every day the CCEE calculates the prices for each hour of the following day, in each submarket, with three computer models, starting from the marginal operating cost and respecting a minimum limit and two maximum limits.
Literal excerpt from the document
Portuguese only“O Preço de Liquidação das Diferenças (PLD) é calculado pela Câmara de Comercialização de Energia Elétrica (CCEE) diariamente para cada hora do dia seguinte, considerando a aplicação dos limites máximos (horário e estrutural) e mínimo vigentes para cada período de apuração e para cada submercado. Este cálculo é realizado por modelos computacionais (Newave, Decomp e Dessem) e tem como base o Custo Marginal de Operação (CMO).”
Documents accessed and text checked on Sep 28, 2026.