Glossary: the terms on your bill and in your system

Your bill

GDMTH tariff.

CFE’s tariff for large demand at medium voltage, time-of-use. It charges for energy according to when you use it (base, intermediate and peak) and charges separately for your demand.

Peak hours.

The most expensive band of the GDMTH tariff. In the Norte division, 18:00 to 22:00 in winter.

Billable demand.

The demand in kW that CFE charges you. It is driven by your maximum demand during peak hours.

Capacity charge.

The GDMTH charge calculated on your billable demand.

Power factor.

How much of the energy your plant draws is turned into useful work. It is written as a percentage (95%) or as a decimal (0.95). If your plant has less than 1 MW of contracted demand, CFE adds a surcharge below 90% and gives a credit above it. With 1 MW or more, the threshold is 97%.

Reactive energy (kVArh).

Energy drawn by motors and transformers that does no work. It lowers the power factor.

Reconciliation.

Each month’s forecast bill compared with the actual bill.

GDMTH tariff guide

Your system

BESS.

Battery energy storage system.

Industrial batteries.

In energy, these are BESS connected to a plant’s electrical system. Forklift batteries and UPS batteries go by the same name, but they do not lower the CFE bill or back up the whole plant.

PCS.

The BESS power conversion system: it converts the batteries’ direct current into alternating current for your plant, and the reverse to charge them.

BMS.

The system that monitors the battery cells.

EMS.

The software that decides when the system charges and discharges. ENEGRIN’s is called Ollin EMS.

Island mode.

When the system runs isolated from the grid and regulates your plant’s voltage and frequency itself.

Peak shaving.

Using the BESS during peak hours so that the demand CFE measures is lower. It lowers billable demand and, with it, the capacity charge.

Load shifting (tariff arbitrage).

Charging the BESS in base hours, when the kWh costs less, and using that energy at peak, when it costs more.

Standby generator (planta de emergencia).

A generator, usually diesel, that starts when the grid fails and powers the plant for as long as it has fuel. It provides backup but does not lower the CFE bill.

Cogeneration.

Generating electricity at your plant and recovering the engines’ heat for process steam, hot water or cooling.

Trigeneration.

Cogeneration that also produces cooling, with an absorption chiller driven by the engines’ heat.

Regulation

Self-consumption (autoconsumo).

The legal category in Mexico’s 2025 Electricity Sector Law for generating, on your own site, the electricity you consume. It requires a plant of 0.7 MW or more and a CNE generation permit.

Isolated self-consumption.

The plant is not connected to the grid and all its output is consumed on site.

Grid-connected self-consumption.

The plant is connected to the grid and can deliver surplus energy to it.

Abasto aislado.

The equivalent category in the previous law. The Electricity Sector Law replaced it with self-consumption.

CNE.

Mexico’s National Energy Commission: it grants generation permits.

CENACE.

Mexico’s National Energy Control Center: the grid operator.

Grid Code.

The grid’s technical rules. Since April 8, 2026, it requires a 0.97 power factor for medium-voltage plants of 1 MW or more and for all high-voltage plants.

Qualified supply.

Buying energy from an authorized private supplier instead of CFE.

Self-consumption guide

Your contract

Shared savings.

The option with no investment: ENEGRIN installs and operates the system and you keep a share of the savings.

Storage as a service.

Market name for a BESS that the provider installs and operates without the client buying the equipment. At ENEGRIN this model is called shared savings and is paid with a percentage of the measured savings.

O&M.

Operation and maintenance fee. If the system does not save in a given month, you do not pay O&M that month.

How contracting works