Entry · Market
GSF: Generation Scaling Factor (MRE adjustment factor)
How much did the hydropower plants of the mechanism generate compared with the physical guarantee?
Acronyms: MME, Ministry of Mines and Energy; PLD, Settlement Price for Differences (spot price); CCEE, Electric Energy Trading Chamber; ANEEL, Brazilian Electricity Regulatory Agency.
In one sentence
Ratio, as a percentage, between the verified generation of the plants of the Energy Reallocation Mechanism (MRE) in the month and the physical guarantee of these plants (in the MME bulletin, the seasonalized physical guarantee). Below 100%, the hydropower plants of the mechanism generated, together, less than the physical guarantee.
Real example
78.9%Nature of the data: Calculated
Aug 2026 · Energy Reallocation Mechanism (SIN)
Source: CCEE, generation by submarket e monthly MRE. Reference up to Aug 2026. Captured on Oct 6, 2026. Dataset code at the source: GERACAO_SUBMERCADO, MRE_MENSAL.
The GSF of the last published month: generation of the MRE plants divided by the physical guarantee modulated and adjusted by the availability factor, in the CCEE open datasets.
The terms of the calculation, in MWavg: 40,397 of generation of the MRE plants divided by 51,185 of physical guarantee modulated and adjusted by the availability factor. With the seasonalized physical guarantee (53,212) in its place, the same generation would give 75.9%. These are two results of the same month and the same generation: only the physical guarantee in the denominator changes. The observatory uses the modulated one adjusted by the availability factor; the MME bulletin uses the seasonalized one.
Calculated: Deterministic transformation made by Scrutiniums, with a published formula.
Why it matters
How it is measured
The GSF is the generation of the MRE plants in the month divided by their physical guarantee, as a percentage. What changes from one source to another is which physical guarantee goes into the denominator; the observatory uses the one modulated and adjusted by the availability factor.
Technical detail: the norm, the sources and the observatory's calculation
In the MME documents. The bulletin compares hydropower generation, labeled "(center of gravity)", with the seasonalized physical guarantee. According to the working group report, the MRE uses the seasonalized and modulated physical guarantee: seasonalization follows the commercial strategy of each agent, and modulation follows the trading rules and the generation profile of the MRE plants.
In the observatory. The denominator is the physical guarantee modulated and adjusted by the availability factor, in the CCEE open datasets, as a percentage, by month, and the result was checked against the monthly InfoMercado factor in some months of the series, listed in the panel.
Unit: percentage, by month (generation in MWavg divided by physical guarantee in MWavg)
Not to be confused with
Physical guarantee is the maximum amount of energy a project can use to prove load coverage or to sell in contracts; the GSF is the ratio between what the MRE plants generated in the month and their physical guarantee, as a whole. A GSF of 80.51% (December 2020, in the MME bulletin, with the seasonalized physical guarantee) does not say that the physical guarantee fell: it says that the generation of the month was below it. A GSF above 100% says it was above.
MRE (Energy Reallocation Mechanism)
The GSF is not the mechanism: it is the monthly number that compares the generation of the MRE plants with their physical guarantee. The mechanism is in the MRE entry.
What cannot be concluded
- The sources do not use the same denominator. The MME bulletin uses the seasonalized physical guarantee; the working group report uses the historical physical guarantees, without seasonalization, in Table 1, and the seasonalized physical guarantee in the figures; the observatory uses the physical guarantee modulated and adjusted by the availability factor. The difference can be large: in the example, the same month gives different results with each denominator. Values from different sources can only be compared after checking the denominator.
- The regulatory definition of the MRE adjustment factor, in the CCEE Trading Rules and in ANEEL regulations, was not read: ANEEL's repository of norms refuses the observatory's automated queries, and the Trading Rules were not read either. The entry describes the GSF as the MME documents use it.
- The check against the monthly InfoMercado factor covers some months of the series, and the month of the example might not yet have a corresponding edition; the list and the divergence of the 12-month figure are in the Market panel (see MRE).
- The GSF is the result of the group of plants of the mechanism, which the bulletin describes as the MRE plants having generated "together"; it is not the performance of a single plant.
Related entries
- MREEnergy Reallocation MechanismThe working group report treats the MRE adjustment factor and the GSF as the same number: the GSF is the monthly result of the mechanism.
- Physical guaranteeIt is the denominator of the ratio, and the sources do not use the same physical guarantee (see what cannot be concluded).
In the learning paths
Official source
In other words: dividing what the MRE plants generated together, 42,500 MWavg, by the seasonalized physical guarantee, 52,788 MWavg, the result is 80.51%, and that is the GSF of the month.
Literal excerpt from the document
Portuguese only“Em dezembro de 2020, as usinas participantes do MRE geraram, juntas, 42.500 MWmédios, ante a garantia física sazonalizada de 52.788 MWmédios, o que representou um GSF mensal de 80,51%.”
Literal excerpt from the document
Portuguese only“GSF - Generation Scaling Factor”
MME, Power Sector Modernization working group (GT)Report of the Thematic Group on MRE Improvement, July 2019, section on the operating balance, p. 38 of the document and of the PDF
In other words: the report treats the MRE adjustment factor and the GSF as the same number.
Literal excerpt from the document
Portuguese only“Com base no comportamento da geração hidrelétrica é possível avaliar o comportamento do fator de ajuste do MRE, conhecido como GSF.”
MME, Power Sector Modernization working group (GT)Report of the Thematic Group on MRE Improvement, July 2019, Table 1, variables assessed, p. 22 of the document and of the PDF
In other words: in this study the GSF is the verified monthly generation divided by the historical physical guarantees, without applying the seasonalization of physical guarantees.
Literal excerpt from the document
Portuguese only“Razão entre a geração verificada (mensal) e as garantias físicas históricas. Neste estudo não será considerado procedimento da sazonalização das garantias físicas para o MRE.”
MME, Power Sector Modernization working group (GT)Report of the Thematic Group on MRE Improvement, July 2019, section on MRE accounting, p. 17 of the document and of the PDF
In other words: the physical guarantee that goes into MRE accounting goes through two steps, seasonalization, which depends on each agent's strategy, and modulation, which follows the trading rules and the generation profile of the plants.
Literal excerpt from the document
Portuguese only“e utiliza a GF sazonalizada e modulada. A sazonalização da GF é realizada em função da estratégia comercial de cada agente, enquanto que a modulação é realizada pelas regras de comercialização e segue o perfil de geração das usinas do MRE.”
MME, Power Sector Modernization working group (GT)Report of the Thematic Group on MRE Improvement, July 2019, section on the recent MRE crisis, p. 21 of the document and of the PDF
In other words: since 2014 the GSF had been below 90%, and this left many hydropower agents exposed to high spot prices.
Literal excerpt from the document
Portuguese only“Os últimos anos foram os mais desafiadores para o MRE desde sua implantação em 2001, especialmente a partir do ano de 2014, período em que o GSF tem apresentado valores abaixo de 90%, o que tem exposto negativamente muitos agentes hidrelétricos a valores elevados de PLD.”
MME, Power Sector Modernization working group (GT)Report of the Thematic Group on MRE Improvement, July 2019, section on the production of the MRE plants (figure 8), p. 18 of the document and of the PDF
In other words (the original reads “faz com o GSF seja inflado”, with a missing word): since hydropower production and the seasonalized physical guarantee do not vary together over the year, the GSF calculated with the seasonalized physical guarantee is artificially high in the wet season, when a lot is generated and the seasonalized physical guarantee is low, and artificially low in the dry season.
Literal excerpt from the document
Portuguese only“O descolamento entre a sazonalidade da produção hidrelétrica e da GF faz com o GSF seja inflado no período úmido (muita geração e baixa GF sazonalizada) e reduzido no período seco (pouca geração e alta GF sazonalizada), provocando oscilações artificiais do GSF e elevando o risco das hidrelétricas.”
Documents accessed and text checked on Oct 7, 2026.
Check details
What the check found in the source
- ANEEL's repository of norms returns 403 to automated requests, and the block was not circumvented.