A Mexican plant on CFE basic supply does not face an hourly electricity price. It faces a demand charge, and that charge is set by one 15 minute interval. Under GDMTH, maximum demand is the average kilowatts over the 15 minute interval with the highest consumption in the billing period, and the capacity charge is applied to the maximum demand that lands inside the punta window.

That single interval is the whole prize in demand management here. The article you are reading was written for plant and facilities managers on medium voltage CFE tariffs, and its argument is narrow on purpose. Demand forecasting software pays in Mexico when it changes the interval that sets demanda facturable. Where it cannot reach that interval, it changes nothing on the invoice, whatever the model is trained on.

What follows separates the demand applications that move a Mexican bill from the ones that move somebody else's.

What a Mexican customer is actually billed for

The tariff class decides whether demand management is even a subject. PDBT covers low voltage services up to 25 kW of maximum demand and carries a fixed monthly charge plus an energy charge, with no demand charge in pesos per kW and no time of use energy price. Smoothing a peak returns nothing to a PDBT customer. Above 25 kW in low voltage, GDBT introduces a measured demand charge.

In medium voltage, GDMTO applies below 100 kW of demand and prices energy at one rate all day. GDMTH applies at 100 kW and above and is the tariff most industrial sites in Mexico sit on. It splits energy into base, intermedia and punta hours, with the ranges set by tariff region, season and day type in the schedules CFE publishes each month, and it adds two separate demand charges on top.

None of these customers sees a price that varies by the hour. Hourly local marginal prices reach a market participant or a usuario calificado buying from a qualified supplier on an indexed contract. Registration as a usuario calificado requires 1 MW of maximum demand at the centro de carga over the previous twelve months. Any demand response pitch built on real time price signals is describing a market a basic supply customer is not in, and moving to qualified supply is a separate decision with its own costs.

How demanda facturable is set under GDMTH

Under GDMTH the billed demand is not one number. It resolves into two, measured differently, and they reward different behavior.

The capacity charge is applied to the maximum demand coincident with the punta period in the billing month. Where a tariff region and season have no punta period, it falls on the maximum measured demand. This charge responds to what the plant did in that month. Shave the punta peak in April and the April capacity charge falls.

The distribution charge is measured differently. It is applied to the lesser of two figures, the maximum demand recorded in the previous year and the maximum demand recorded in the billing month. The CRE set that criterion in acuerdo A/001/2018 of 1 February 2018 and recorded it in its Memoria Documental on final basic supply tariffs of 31 October 2018. It does not ratchet. A month in which the plant never approaches its historic peak is billed on that month's own maximum demand.

That split is the argument for prediction rather than reporting. The capacity charge does not follow the plant's highest kilowatt of the month. It follows the highest kilowatt inside punta, and punta is a window CFE publishes in advance, which is what makes the interval controllable at all. A monthly bill review tells a manager about a peak that has already been billed. A model that flags a punta coincident peak building twenty minutes out, so that a compressor is staggered or a battery discharges into it, defends the kilowatt figure before it is set. That is the calculation to put in front of a finance director, and it can be run on the site's own bills before anyone quotes software.

What demand forecasting can and cannot do at a plant

Three different forecasting products get discussed as if they were one. CENACE forecasts the Sistema Eléctrico Nacional in order to dispatch it. A supplier forecasts a portfolio in order to hedge it. A plant forecasts its own load in order to protect a demand charge. Different buyers, different data, different payback. Only the third is available to a load center, and confusing it with the first two is how a plant ends up evaluating software it cannot use.

A site level model needs two inputs the average Mexican plant does not have. The first is interval metering at the main incomer rather than a monthly reading. The second is submetering on the loads capable of setting a peak, because a model that cannot attribute a peak to a machine cannot pre-empt it. Metering and monitoring is therefore the first purchase, not the second. A dispatch model trained on monthly totals has nothing to learn from.

Where those inputs exist, the work is specific and unglamorous. The model learns which combinations of chillers, compressors, furnaces, test cells and electric ovens tend to coincide, then staggers starts or curtails the lowest value load in the seconds before the coincidence forms. Battery storage does the same job without touching production, which is why it competes directly with control logic rather than complementing it.

Two limits should be stated plainly. Load shifting does not reduce consumption, so the energy line of the bill moves only by the spread between the punta and base charges on the kWh actually moved. And shifting load into other hours does not automatically lower emissions, because the generation mix in those hours is a product of CENACE dispatch rather than of the plant's schedule. Cost and carbon are separate levers here and should be presented separately.

The one formal demand response product in Mexico, and who can reach it

Mexico does have a demand response mechanism, and almost no reader of a general article about it can use it. SENER published the Manual del Mercado para el Balance de Potencia in the DOF on 22 September 2016. Under that manual, a load entity's annual capacity requirement is set by its average demand during the 100 critical hours identified for its power zone in the production year, multiplied by one plus the minimum planning reserve.

Recursos de Demanda Controlable Garantizada participate on the supply side of that balance. CENACE published the disposiciones for registering their cost and capacity parameters in the DOF on 5 January 2017. A resource cannot accrue availability above its own consumption in the hour, and when CENACE activates it the avoided load reduces the entity's annual capacity requirement rather than counting as delivery.

The catch is who qualifies. Only an entidad responsable de carga in the Mercado Eléctrico Mayorista has this obligation and this option. A basic supply customer's share is bundled into the CFE tariff and cannot be traded. Direct participation in the MEM requires 5 MW plus 20 GWh a year under SENER's Manual de Registro y Acreditación de Participantes del Mercado, published in the DOF on 15 July 2016. For a site that does clear those thresholds, the forecasting target changes completely. It is no longer the punta window on a published schedule but 100 hours a year that are only known with certainty after the fact.

What would make this read wrong

The tariff rules are administrative acts. The CRE can amend the capacity and distribution demand definitions, and a change to either demand base would move the case for predictive peak control in the same month it took effect.

Power factor is the cheaper problem and is often the larger one. Under the SHCP acuerdo published in the DOF on 31 October 2000, a billing period average power factor below 90% lagging triggers a surcharge applied to the invoice amount, capped at 120%, with the corresponding bonus capped at 2.5%. The CRE reissued the Código de Red as RES/550/2021, published in the DOF on 31 December 2021 and in force from 1 January 2022. Its power factor band of 0.95 lagging to 1.0, measured in five minute intervals, is not enforceable until 8 April 2026. Capacitors and reactive compensation usually pay back before any control platform does, and switching loads around can make power factor worse.

There is also a production test that no software passes on its behalf. Curtailing a load to hold a peak down is worth doing only when the contribution margin given up is smaller than the demand charge avoided, and at a plant running near capacity it frequently is not. That comparison belongs to the operations director, not to the model.

See whether demand management would move your CFE bill

Pull twelve months of CFE bills and your tariff class, and add interval meter data at the main incomer if you have it. Mexico Energy Partners will identify the interval that set demanda facturable in each month, list the loads running in it, and say whether controlling those loads would pay for itself against the charge it avoids. Where the answer is no, we will tell you that instead.

Sources

• Comisión Reguladora de Energía, Tarifas Finales del Suministro Básico, Memoria Documental, 31 October 2018. Capacity charge assigned to demand coincident with the punta period for GDMTH, DIST and DIT. Acuerdo A/001/2018 of 1 February 2018 set the distribution charge on the lesser of the maximum demand of the previous year and the maximum demand of the billing month.
• CFE, tariff schedules for PDBT, GDBT, GDMTO and GDMTH. Voltage levels, the 25 kW and 100 kW demand thresholds, and the charge components of each class.
• SENER, Manual del Mercado para el Balance de Potencia, DOF 22 September 2016. The 100 critical hours, the minimum planning reserve, and the participation of Recursos de Demanda Controlable Garantizada.
• CENACE, Disposiciones para el registro de parámetros de costos y capacidad de las Unidades de Central Eléctrica y de los Recursos de Demanda Controlable Garantizados, DOF 5 January 2017.
• SENER, Manual de Registro y Acreditación de Participantes del Mercado, DOF 15 July 2016. The 5 MW plus 20 GWh a year threshold for direct participation in the MEM.
• Comisión Reguladora de Energía, RES/550/2021, Código de Red, DOF 31 December 2021, in force 1 January 2022.
• SHCP, acuerdo que autoriza el ajuste a las tarifas para suministro y venta de energía eléctrica, DOF 31 October 2000. Power factor surcharge and bonus.