Mexico's Mercado Eléctrico Mayorista (MEM) has been trading since 2016 under the Bases del Mercado Eléctrico published in the DOF on 8 September 2015, and the question plant directors and CFOs still ask is the practical one. Who does an industrial site actually sign a power contract with? The answer is set by a registration taxonomy in the Ley de la Industria Eléctrica and the Manual de Registro y Acreditación de Participantes del Mercado, and misreading it costs months of process time.

Six categories of Participante del Mercado exist under that Manual. A manufacturing plant in Mexico can contract with two of them, may become one of them if its load is large enough, and will never sign an energy contract with the other three. A facility that assumes it has to trade in the wholesale market in order to leave CFE Suministro Básico has the structure backwards.

What follows maps the actors in the MEM, states what each is permitted to do, and identifies which ones are counterparties for an industrial buyer. The commercial comparison between a fixed-price contract and floating exposure to the spot price sits in a separate piece on power purchase agreements against the wholesale spot market.

The six registered participant categories

The Manual de Registro y Acreditación de Participantes del Mercado recognises Generador, Suministrador de Servicios Básicos, Suministrador de Servicios Calificados, Suministrador de Último Recurso, Comercializador no Suministrador, and Usuario Calificado Participante del Mercado. Registration is with CENACE, which signs the Contrato de Participante del Mercado and registers the Centros de Carga that sit behind each participant.

Three of those six sell energy to end users. The Suministrador de Servicios Básicos serves regulated retail customers at tariffs approved by the Comisión Reguladora de Energía (CRE). The Suministrador de Servicios Calificados sells to Usuarios Calificados, and LIE Article 48 places that supply expressly in conditions of free competition, which is why a suministro calificado contract has a negotiated price rather than a published tariff. The Suministrador de Último Recurso exists to catch load whose supplier fails, on a temporary basis and at a CRE-regulated price.

The Comercializador no Suministrador trades in the market without serving final load. A Generador holds a CRE generation permit and sells energy, potencia and Certificados de Energías Limpias. Neither of those two is a direct counterparty for a plant's supply contract, though a generator is very often the party behind the price a supplier quotes you.

Who is outside the participant list entirely

Three bodies an industrial buyer deals with constantly are not market participants at all. CENACE operates the Sistema Eléctrico Nacional and the MEM, runs interconnection studies, and dispatches generation. It is the system and market operator, not a seller of power. CRE is the regulator: it issues generation and supply permits, approves regulated tariffs, and maintains the Registro de Usuarios Calificados under the disposiciones administrativas published in the DOF on 6 December 2017. SENER sets policy and issues the sector's manuals.

The Transportista and the Distribuidor sit in a fourth position. CFE Transmisión operates the Red Nacional de Transmisión under CENACE's instruction and CFE Distribución operates the Redes Generales de Distribución. A plant pays them through the CRE-regulated transmission and distribution charges known as porteo, and it pays those charges whoever supplies its energy. Migrating away from CFE Suministro Básico changes the energy and potencia line items on the bill. It does not remove porteo.

One more category sits outside the market: the Generador Exento. Generation below 0.5 MW interconnected to a distribution network operates under the SENER Manual de Interconexión de Centrales de Generación con Capacidad menor a 0.5 MW (DOF, 15 December 2016) and requires no CRE generation permit. That threshold is a capacity limit on the generating plant, not a limit on the facility's load.

Where CFE sits after the split

CFE is a market participant, not a regulator, and it is not one company for these purposes. Its generation business was separated into six subsidiaries, CFE Generación I through VI, created by acuerdos published in the DOF on 29 March 2016. Supply was split as well, with CFE Suministro Básico serving regulated customers and CFE Calificados competing as a Suministrador de Servicios Calificados.

The practical consequence for a buyer is that CFE Calificados bids against private suppliers for the same load. An industrial site that migrates to suministro calificado is not obliged to leave CFE, and in some locations the incumbent's affiliate submits the sharpest offer. Treat it as one bidder among several.

What Usuario Calificado status requires, and what it does not

The threshold for registration as a Usuario Calificado is 1 MW of demand. It is not an annual consumption figure in MWh. The SENER acuerdo published in the DOF on 1 March 2017 defines that demand for a medium or high tension site with recent service as the maximum demand in kW recorded over the preceding 12 months, and it permits aggregation of Centros de Carga to reach the threshold. CRE issues the registration.

A separate and much higher threshold is the one that trips up finance teams reading secondary sources. To register as a Usuario Calificado Participante del Mercado and buy directly in the MEM under a Contrato de Participante del Mercado with CENACE, CRE's Preguntas Frecuentes sobre el Registro de Usuarios Calificados sets the bar at demand of at least 5 MW and annual consumption of at least 20 GWh. That is where the annual-consumption number comes from, and it applies only to direct participation.

Most industrial sites in Mexico sit between those two thresholds. They register as Usuarios Calificados and buy through a Suministrador de Servicios Calificados, which carries the market settlement, the potencia obligation and the credit exposure on their behalf. That is the ordinary path, not a compromise. Direct participation adds daily market operations, collateral and settlement staff to a manufacturing business that has no reason to build them.

Five checks on a prospective counterparty

Five checks separate a workable shortlist from a stack of quotes that cannot be compared.

• Confirm the bidder's registration category with CENACE. A Comercializador no Suministrador cannot serve your load, whatever its proposal says.
• Confirm the CRE permit behind the offer, and whether the energy is contracted from a specific plant or bought in the market and resold.
• Ask which party holds the Contratos de Cobertura Eléctrica. LIE Article 52 gives CRE the power to set minimum coverage requirements on Suministradores, and a supplier operating near the minimum is passing spot exposure back to you.
• Establish whether the quoted price includes porteo, potencia and Certificados de Energías Limpias, or only energy. Offers that differ only in what they bundle are not comparable.
• Check the demand basis used for your Usuario Calificado registration and whether aggregation across sites is being assumed.

The taxonomy is not administrative trivia. It determines which quotes are real, which registration you need, who carries settlement risk, and how long the process runs before power flows under the new contract. Our view is that the single most common error in Mexican industrial procurement is treating market structure as a legal formality to be resolved after the price is agreed. It sets the price.

Review which market role your facility should take

Mexico Energy Partners can review a facility's demand profile against the Usuario Calificado threshold, confirm which counterparty categories can legitimately serve the site, and identify the bill components that change on migration. An initial review needs 12 months of CFE billing, interval demand data where the meter records it, and the voltage level and tariff class currently applied. See how we structure that work in energy procurement and how the rules that govern it are moving in regulatory policy.

Request a review of your facility's market participation options