Across the CFE bills Mexico Energy Partners has analyzed for industrial clients, demand-related charges run from 30% to over 50% of the monthly total. At one automotive client, referred to here as INDUSTRIAX, demand charges carried over 45% of total energy expenditure before any intervention. Cutting grid draw during the high-cost hours removed over MXN 3.6 million a year from that plant's bill.

Most plants on the Gran Demanda en Media Tensión Horaria tariff manage the kWh and leave the kW alone. That is the expensive half. The decision this brief helps a CFO or procurement manager evaluate is whether to spend capital on peak shaving, reschedule load for nothing, or do neither, and what data settles the question.

Start with a correction, because it changes the answer. GDMTH does not levy one demand charge on your punta peak. It levies two demand-related charges, in pesos per kW, and they are set by different measurements.

What GDMTH actually bills

A GDMTH invoice has an energy side and a demand side. The energy side, the cargo por energía, prices kWh separately across three time-of-use periods: base, intermedio and punta. That is the part most cost programs attack, by moving consumption out of punta.

The demand side is billed per kW and splits into two charges. The cargo por capacidad is driven by the maximum demand your site registers during the punta period. The cargo por distribución is driven by the maximum demand registered in the month across all periods, punta included. CFE registers demand in 15-minute intervals, so a single interval can set the figure that prices the whole month.

Both are billed in Mexican pesos per kW, not in dollars. Any model built in USD has to state the exchange rate and the month it was taken, because CFE republishes the rate tables monthly and the tariff itself moves.

While you are isolating the demand lines, isolate the power factor adjustment as well. CFE applies a bonus or a penalty to the bill according to the site's measured power factor, and correcting it is usually cheaper than any of the measures discussed here. The power factor bonus and penalty on the CFE bill is a separate calculation from demand and is often left uncorrected for years.

Why the punta maximum is not the whole story

The practical consequence of two demand charges is that peak shaving does not reduce both by the same amount. Hold your punta demand down by 500 kW and the capacity charge falls with it. The distribution charge only falls if the month's overall maximum demand also falls, and at many plants that maximum is set outside punta, by a morning start-up or a mid-shift coincident load.

This is where most peak shaving business cases lose their return. A model that applies the full demand rate to the full punta reduction will overstate the saving, because it prices distribution as though it moved when it did not. Before sizing anything, split your own bill into cargo por capacidad and cargo por distribución and check which of the two is larger at your site.

Two site-specific facts also have to be pinned down. The punta, intermedio and base windows are published by CFE by tariff region and by season, so a plant in one division does not face the same hours as a plant in another. And the equipment that sets your monthly maximum is a question for interval data, not for a monthly bill. Interval metering and monitoring is what turns a 15-minute record into a list of which starts to stagger.

What the demand charge costs

The 30% to over 50% range above is Mexico Energy Partners' own observation across client bill analyses. It is not a market statistic, and it is skewed. Plants come to MEP because their bills are already a problem, so the range describes sites with a demand issue rather than the average Mexican industrial user. Treat it as a reason to check your own split, not as a benchmark.

The INDUSTRIAX figure needs the same handling. Demand charges carried over 45% of that plant's total energy expenditure. A short daily production ramp in the early evening was setting the punta maximum, and reducing grid draw in those hours removed over MXN 3.6 million a year. MEP has not published the measurement and verification protocol behind that number, the baseline period, the reporting period, or the split between what came off the demand charge and what came off the energy charge. INDUSTRIAX is an anonymized client designation, and the plant's connected load is not disclosed, so the peso figure cannot be scaled to another site. What transfers is the diagnosis, not the number.

Peak shaving, and the two cheaper levers first

Peak shaving means using onsite resources, usually solar PV paired with battery storage for industrial plants, to hold the demand seen by the CFE meter below a set threshold. When internal demand ramps during punta, the battery supplies the difference and the meter never sees the peak. It works, and it is the most capital-intensive answer available.

Two cheaper levers should be tested first because they cost little or nothing. The first is start-up sequencing. Synchronized starts of furnaces, compressors and large motor arrays create coincident demand spikes that have nothing to do with production volume, and staggering them by a few minutes can move the monthly maximum. The second is power factor correction, which is capacitor work rather than a generation project.

One limitation on the capital option. A battery sized for demand management holds a threshold across the punta window and nothing more. Riding through a grid outage requires different sizing, an inverter capable of islanding and a transfer scheme, all at additional cost. Resilience and demand management are two products, and buying one does not deliver the other.

What to do next

• Split 12 months of bills. Isolate the cargo por demanda facturable, and inside it separate cargo por capacidad from cargo por distribución. Track each as a percentage of the monthly total. That quantifies the exposure and tells you which of the two charges is worth attacking.
• Find what sets the monthly maximum. Pull 15-minute interval data for a full billing cycle and match the highest intervals to production events. Name the specific equipment and the time of day. If the maximum sits outside punta, peak shaving alone will not move your distribution charge.
• Model peak shaving against the correct billed quantity. Apply the reduction to cargo por capacidad and to cargo por distribución separately, using the CFE rates for your division and a stated month, and state the exchange rate if the model runs in dollars. Rates are republished monthly, so a model that does not name its month cannot be checked.

Onsite generation does more than cut a charge. It fixes part of your cost base against tariff movement and it contributes to corporate emissions targets. Those are real, and neither is a reason to skip the three steps above.

Find out what your demanda facturable is actually costing you

Send twelve consecutive CFE GDMTH invoices and tell us your CFE division. Mexico Energy Partners will return the split of your billed demand between capacity and distribution, plus the share of each monthly bill the demand charges carried. We also give you the kW a peak shaving system would remove from the billed quantities, rather than from your punta maximum. If you have 15-minute interval data, include one full billing cycle and we will identify which equipment starts are setting the month. We confirm what else is needed within two business days. Nothing is promised on savings until your own bills have been reviewed.

Sources

• Comisión Federal de Electricidad, Gran Demanda en Media Tensión Horaria tariff schedule, as published and in force in August 2025. Charge components, the split between cargo por capacidad and cargo por distribución, the pesos per kW basis, and the publication of punta, intermedio and base windows by region and season.
• Consejo Consultivo de Eficiencia Energética Aplicada, published explanation of the GDMTH tariff. Capacity charge driven by maximum demand in the punta period and distribution charge driven by the month's maximum demand.
• COMPITE and GIZ, Tarifas Eléctricas: Tutorial para el trabajo en campo, Mexico City, 2015. Structure of billed demand under CFE's time-of-use medium voltage tariffs.
• Mexico Energy Partners CFE bill analyses across industrial client engagements. Source of the 30% to over 50% demand charge range and of the INDUSTRIAX figures.