CENACE settled the Mercado de Balance de Potencia for production year 2023 at a closing price of 6,549,608.65 pesos per MW-year in the Sistema Interconectado Nacional. The equivalent price for production year 2022 was 3,184,022.03 pesos per MW-year. Both figures come from CENACE's own executive reports on the market, published in March 2023 and February 2024. The cost of an uncovered megawatt of capacity in the national grid more than doubled in one cycle.

The mechanism behind that number is the part most industrial buyers get wrong. CENACE runs this settlement once a year, after the production year has closed. It is not a real-time market and load does not bid into it. Your obligation is calculated from the average power your site drew from the grid during 100 particular hours of the year just ended, and CENACE identifies those hours after the fact.

That is the decision in one line. Load carried in 100 hours you cannot see coming is a priced quantity, and the price has been moving. What follows is the arithmetic that turns those hours into pesos, and the test for whether your plant is exposed to it at all.

How CENACE calculates your capacity obligation

The rules sit in the Manual del Mercado para el Balance de Potencia, published by the Secretaría de Energía in the Diario Oficial de la Federación on 22 September 2016, under the Bases del Mercado Eléctrico of 8 September 2015. Two definitions carry the calculation. Capacidad Demandada, at section 1.3.5 of the manual, is the average power an Entidad Responsable de Carga drew from the Sistema Eléctrico Nacional during the Horas Críticas of a given year. Requisito Anual de Potencia, at section 2.2.2, is that figure grossed up by the Reserva de Planeación Mínima. For production year 2023, CENACE applied indicative minimum reserve values of 7.7% in the SIN, 8.6% in Baja California and 13.8% in Baja California Sur. A load averaging 10 MW across the SIN critical hours therefore owed 10.77 MW-year of capacity.

The critical hours changed definition in 2018. Sections 3.3 and 3.4 of the manual set them as the 100 hours of highest demand for 2016 and 2017, and from 2018 as the 100 hours of lowest generation reserve, meaning available generating capacity less firm demand. Those are not the same hours. Reserve margin collapses when large units trip or when hydro and wind under-deliver, and that does not always land on system peak. CENACE reports that the SIN critical hours for production year 2023 ran from 22 March to 13 December. In Baja California they fell between 4 July and 22 September.

Who actually carries the obligation

Article 54 of the Ley de la Industria Eléctrica, published in the DOF on 11 August 2014, places the capacity requirement on Suministradores and on Usuarios Calificados Participantes del Mercado. Those are the Entidades Responsables de Carga. An industrial site is not automatically one of them, and that difference decides whether any of this is actionable for you.

A plant registered with the CRE as a Usuario Calificado Participante del Mercado holds the obligation directly. Its Capacidad Demandada is its own metered draw in the critical hours, so every megawatt it avoids in those hours cuts the requirement it must cover the following February. Sites weighing registering as a Usuario Calificado should price this line before they decide, because it moves from invisible to owned on the day the registration takes effect.

A plant buying through a Suministrador de Servicios Calificados does not hold the obligation. The supplier does. Whether the site sees any benefit from shaving critical-hour load depends on how the supply contract allocates capacity cost. A contract that recovers capacity as a flat adder per MWh pays the plant nothing for curtailing. A contract that passes through the site's own Capacidad Demandada pays it in full. That clause is negotiable at renewal, and most buyers never read it.

A plant on CFE basic supply is further away still. CFE Suministro Básico is the Entidad Responsable de Carga, and the CRE issues the final basic supply tariffs under article 12 of the same law. Capacity cost reaches that plant inside a regulated charge that is not computed from its own demand in CENACE's critical hours. Demand management still pays on a GDMTH bill through the cargo por capacidad and the cargo por distribución, but that is a separate mechanism on different hours.

What one MW of coincident demand is worth

Take the SIN closing price for production year 2023 and the 7.7% reserve. One MW of average demand avoided across the 100 critical hours removes 1.077 MW-year of requirement, worth 7,053,928 pesos at that price. At the production year 2022 price the same megawatt was worth 3,429,192 pesos. That is the range a plant should hold in view before it spends anything on load control.

Two limits on that figure matter. The closing price applies to the residual, not to the whole obligation. CENACE reported an estimated purchase obligation of 45,473.48 MW-year in the SIN for production year 2023 and 4,388.54 MW-year actually acquired through the balance market, under a tenth of the total. Most capacity is already covered by Contratos de Cobertura Eléctrica at contracted prices, which is also how capacity prices are set in the wholesale market for the majority of load. The closing price is therefore the market's mark for an uncovered megawatt, the right number for a marginal decision and the wrong number for a budget line already under contract.

What happens when the obligation is not covered

A first shortfall is settled and fined, not switched off. Nothing in the Manual del Mercado para el Balance de Potencia disconnects a plant that fails to cover its capacity requirement. Article 165 of the Ley de la Industria Eléctrica reserves temporary or definitive suspension of service for an infractor in contumacia, at the end of a repeated sanction path. The exposure is financial and regulatory.

The CRE published the sanction criteria in Acuerdo A/004/2019, in the DOF on 10 April 2019. The penalty is set from a matrix driven by the shortfall as a share of the obligation, in bands running from 0 to 25% up to 76 to 100%, and it rises where the participant has failed before. The bounds come from article 165, fracción IV of the Ley de la Industria Eléctrica, which sets 6 to 50 units of account per megawatt, and article 166 puts the power to impose the sanction with the CRE. This sanction sits on top of the settlement. It does not replace it.

The gap is real. CENACE's February 2024 report shows a net capacity obligation of 4,394.19 MW-year in the SIN for production year 2023 against 3,775.58 MW-year covered, leaving 618.62 MW-year uncovered, and it lists 21 market participants that closed the year with obligations outstanding.

What could make this read wrong

The price series is two points, which is thin evidence for a trend. Baja California moved from 3,849,625.10 to 4,446,282.56 pesos per MW-year between production years 2022 and 2023, a rise of about 15%, while the SIN roughly doubled. A national number does not travel to a zonal decision.

Supply is the other variable. CENACE canceled the fourth long-term auction, SLP-1/2018, on 31 January 2019, and no long-term auction has been called since. Any advice that tells an industrial buyer to watch the auction calendar is describing a calendar that does not exist. If firm capacity does arrive through other routes, the residual this market has to clear shrinks and the closing price falls back toward the 2022 level.

The hours themselves are the hardest limit. No plant can curtail into a definition of lowest reserve margin that CENACE resolves months after the fact. What a plant can do is lower the probability of running at full draw when reserve is tight, which is a statistical exercise rather than a switch.

What to do before the February market

Pull the site's 15 minute interval demand for the last full calendar year. Overlay the list of 100 critical hours CENACE publishes for that year and that power zone. The average of your draw across those hours is your Capacidad Demandada, and it is the only figure in this article specific to your plant. Multiply it by one plus the zonal reserve, then by the published closing price, and you have what the exposure was worth in pesos.

Then read the supply contract. If capacity arrives as an adder per MWh, ask the supplier at renewal for a pass-through tied to measured Capacidad Demandada, and price the clause both ways before you choose. That is the change with the shortest path to the P&L, and it belongs on the energy procurement agenda rather than the engineering one. On sites that already control load for GDMTH demand charges, extending that control to reserve-margin events is usually a change to controller logic rather than new equipment. Weigh that cost against the peso figure above.

Price your plant's critical-hour exposure

Mexico Energy Partners will take twelve months of interval demand data for the site, the CFE bills or the qualified supply contract, and the CENACE critical-hour list for the relevant zone and year. We return the site's Capacidad Demandada, the Requisito Anual de Potencia it implies, what that was worth at the published closing price, and which contract clauses decide whether curtailment ever reaches your bill. You supply the data, we return the calculation and every assumption behind it. This is analysis of your own data, not a promise of savings or of any market outcome.

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Sources

• Centro Nacional de Control de Energía, Informe Ejecutivo del Mercado para el Balance de Potencia 2024, Año de Producción 2023, February 2024.
• Centro Nacional de Control de Energía, Informe Ejecutivo del Mercado para el Balance de Potencia 2023, Año de Producción 2022, March 2023.
• Secretaría de Energía, Acuerdo por el que se emite el Manual del Mercado para el Balance de Potencia, Diario Oficial de la Federación, 22 September 2016.
• Secretaría de Energía, Acuerdo por el que la Secretaría de Energía emite las Bases del Mercado Eléctrico, Diario Oficial de la Federación, 8 September 2015.
• Congreso de la Unión, Ley de la Industria Eléctrica, Diario Oficial de la Federación, 11 August 2014.
• Comisión Reguladora de Energía, Acuerdo A/004/2019 por el que se expiden los criterios para la imposición de sanciones derivadas del incumplimiento en la adquisición de potencia, Diario Oficial de la Federación, 10 April 2019.
• Centro Nacional de Control de Energía, comunicado sobre la cancelación de la Subasta de Largo Plazo SLP-1/2018, 31 January 2019.