Industrial energy glossary

Your CFE bill

Billable demand (demanda facturable)

The demand value on which CFE charges you the capacity and distribution charge. It is not your consumption: it is the power peak recorded, and a fifteen-minute simultaneous start can set the charge for all thirty days.

Demand charge (cargo por demanda)

The part of your bill that pays for available power, not for energy consumed. When it exceeds 25 % of the total, storage starts to make a case.

GDMTO

Ordinary Large Demand at Medium Voltage (Gran Demanda en Media Tensión Ordinaria). Tariff for load centers at medium voltage with demand below 100 kW: a single energy price plus the demand charge.

GDMTH

Hourly Large Demand at Medium Voltage (Gran Demanda en Media Tensión Horaria). The most common industrial tariff above 100 kW: three energy prices by time of day (off-peak, mid-peak and peak) plus the demand charge.

DIST

Industrial Demand at Subtransmission (Demanda Industrial en Subtransmisión). Tariff for load centers connected at high voltage, above 35 kV and below 220 kV.

DIT

Industrial Demand at Transmission (Demanda Industrial en Transmisión). Tariff for load centers connected at high voltage of 220 kV or more.

Peak hours (horario de punta)

The time of day when energy costs the most. It is also, almost always, the time when solar generation is worth zero — which is why solar without storage touches consumption but not the peak.

Contracted demand (demanda contratada)

The power you agreed on with CFE. If your measured demand is well below it, you are overpaying; if it exceeds it, you are already at the thermal limit of your installation.

Power quality

Power factor

The ratio between the power your plant actually uses and the power the grid delivers to it. It drops with motors, unloaded transformers and starts. Below the threshold there is a penalty; above it, a bonus.

Reactive power (potencia reactiva, kVAr)

The power that flows back and forth between the grid and your inductive loads without producing useful work. It is what a capacitor bank corrects.

Harmonic distortion (distorsión armónica, THD)

Distortion of the current or voltage waveform caused by non-linear loads. It heats transformers and conductors, trips protection for no apparent reason and degrades electronic equipment.

Non-linear loads (cargas no lineales)

Variable frequency drives, induction furnaces, rectifiers, welding equipment, switched-mode power supplies. They draw current in pulses and are the source of harmonics.

Resonance (resonancia)

When the capacitance of a correction bank and the inductance of the installation coincide at the frequency of a harmonic, the current is amplified instead of corrected. It is why a poorly sized bank makes the problem worse.

Harmonic filter (filtro de armónicos)

Equipment that drains harmonic currents before they circulate through your installation. It is sized on the measured spectrum, not on the motor's rating.

Thermography (termografía)

Infrared camera inspection of panels, splices and connections. It detects the hot spot before it becomes a failure.

Measurement and verification

Class A analyzer (analizador Clase A)

A power quality measuring instrument whose accuracy and calculation method meet the highest class of the standard. Two different Class A analyzers, at the same point and at the same time, must give the same result.

IEC 61000-4-30

The international standard that defines how power quality parameters are measured: what is aggregated, over what window and with what accuracy. It is what makes a compliance report comparable and defensible.

Measurement campaign (campaña de medición)

The period during which the equipment stays installed and recording. For Grid Code purposes, a minimum of seven calendar days per site, to capture the full operating cycle including weekends and shutdowns.

Adjusted baseline (línea base ajustada)

The consumption the result is compared against, corrected for the variables that changed and have nothing to do with the project: production, weather, shifts. Without adjustment, any savings are debatable.

IPMVP

International Performance Measurement and Verification Protocol. It defines how to prove that savings occurred. It is what makes an efficiency project bankable.

Investment-Grade Diagnostic (diagnóstico con grado de inversión)

An energy study whose level of detail and rigor supports an investment decision: adjusted baseline, M&V plan, quantified uncertainty and return calculated measure by measure.

Regulations and authorities

Grid Code

The administrative provisions that set the efficiency, quality, reliability, continuity, safety and sustainability criteria for the National Electric System (Sistema Eléctrico Nacional). The instrument in force is RES/550/2021, published in the DOF on December 31, 2021.

Load center (Centro de Carga)

The installation that receives energy from the system at a point of connection. It is the figure to which Grid Code obligations apply.

Electricity Sector Law (Ley del Sector Eléctrico, LSE)

The law that governs the electricity industry in Mexico today. It replaced the Electricity Industry Law (Ley de la Industria Eléctrica).

CNE

National Energy Commission (Comisión Nacional de Energía). The sector regulator; it took over the functions of the former Energy Regulatory Commission (Comisión Reguladora de Energía).

CENACE

National Energy Control Center (Centro Nacional de Control de Energía). It operates the system and defines the interconnection and connection studies.

Distributed generation (generación distribuida)

Generation at the point of consumption, below the threshold that requires a permit. It is GTO Energy's territory.

Exempt generation (generación exenta)

Generation below 0.7 MW, which does not require a generation permit. It is the scheme for the commercial and industrial solar systems we install.

Equipment and systems

BESS

Battery Energy Storage System. Behind the meter it serves to shave the billable peak, keep the process running through an outage and defer a service upgrade.

Peak shaving (recorte de pico)

A storage operating strategy: charge during off-peak hours, discharge during peak, so that the recorded maximum demand drops and the billable charge with it.

Cogeneration

Simultaneous production of electricity and useful heat from a single fuel input. It only makes a case when the plant already burns fuel continuously to produce heat.

Absorption chiller (chiller de absorción)

Equipment that produces chilled water using heat instead of electricity. It makes it possible to turn heat recovered from an engine into air conditioning or process cooling.

Service entrance (acometida)

The point and installation through which the grid delivers energy to your plant. Upgrading it depends on CFE and on the capacity available in the area.

Substation (subestación)

The assembly that steps medium voltage down to the voltage your installation uses, with its protection, metering and switching.

Live-line work (trabajo en línea energizada)

Medium-voltage maintenance performed without de-energizing the supply. It is a specific capability, for plants whose process cannot stop.

Protection coordination

The setting of the protection devices so that, in a fault, only the nearest device operates and the whole plant does not go down. It is recalculated every time the installation grows.