On April 16, 2026, the Mexican National Energy Commission (“CNE”) published in the Official Journal of the Federation the General Administrative Provisions for the Integration of Battery Energy Storage Systems (“BESS”) into the National Electric System (the “Provisions”). The CNE also repealed regulations on this subject published in March 2025, a few days before the enactment of the new Electricity Sector Law.

The Provisions cover several storage technologies, such as electrochemical (batteries), mechanical, pumped hydro, gravitational, among others, and establish the requirements to integrate BESS into the National Electric System (“SEN”), applicable guidelines for the services to be provided, the participation modalities, and the rules for aggregated installation.

Permits.

A key aspect of the Provisions is the distinction between BESS that require permits and those that do not. Only non-associated BESS, that is, systems not linked to a power plant or a load center, with a capacity equal or greater than 0.7 MW require a storage permit issued by the CNE. Conversely, BESS associated with power plants or load centers, including self-consumption schemes, do not require a permit.

No fixed storage percentage is required for renewable projects.

The Provisions do not establish a fixed percentage of storage capacity as a requirement for interconnecting renewable power plants. Instead, they provide that the effects of such plants on reliability shall be mitigated, as a matter of priority, through system resources, ancillary services, and operational mechanisms determined in the interconnection studies.

Notwithstanding the above, the National Center for Energy Control (“CENACE”) may impose specific requirements on any given power plant, which may be met through the integration of a dedicated or an aggregated BESS, taking into account the project’s location, grid topology, availability of existing or planned flexible resources, and the reliability conditions of the SEN (system-wide variability analysis).  Degradation of the BESS will be relevant for restoring or updating its required capacity.

Importantly, BESS with a storage duration equal to or greater than three hours may offer capacity for purposes of the Capacity Balance Market.

Integration Modalities.

The Provisions outline several ways to integrate BESS into the SEN:

BESS associated with power plants are exclusive to renewable energy projects. They allow for the storage of energy generated by the plant itself or purchased from the grid, offset the variability of the primary energy source, and participate in the Wholesale Electricity Market (“MEM”) in either discharge or charge mode. The capacity of the BESS must be less than the net installed capacity of the power plant.

BESS associated with load centers are considered part of the facilities and equipment of the respective load center. The stored energy is intended exclusively for on-site consumption and cannot be fed into the grid or sold. These systems are charged from the connection point without exceeding the contracted load.

BESS associated with self-consumption may be installed by both holders of electricity generation permits and self-consumption users. Their capacity must not exceed the one authorized in the permit, and its use is only for self-consumption purposes. Interconnected self-consumption projects deploying variable sources, which intend to sell surplus electricity, must meet a backup requirement by either integrating a BESS or contracting a hedge.

BESS associated with transmission and distribution infrastructure are considered the exclusive property of the Federal Electricity Commission (“CFE”) and are used to strengthen the reliability, quality, and efficiency of the SEN. As part of the government’s binding planning, CENACE, with support from CFE, shall propose to the Department of Energy (“SENER”) the nodes or circuits suitable for the installation of BESS in the SEN.

Also, non-associated BESS operate independently and may participate in the MEM as storage entities or be represented by other participants such as generators or suppliers. They require a storage permit, and when contracting with CENACE, they may provide services such as frequency regulation, contingency backup, services for the integration of renewables, and congestion reduction. In this regard, on May 15, 2026, SENER published a call for proposals for strategic generation and storage projects, aimed specifically at this modality.

Finally, with respect to aggregated BESS, the Provisions allow for two or more participants to jointly invest in a BESS, sharing ownership and benefits. This aggregation may take place only in compliance with the binding planning instruments and among participants of the same type (generators, qualified users, etc.), as well as designating commercial and technical representatives before CENACE and CFE.

Transitory Provisions.

On May 22, 2026, the CNE published the forms to apply for storage permits. CENACE shall publish the variability analysis methodology no later than July 15, 2026. Until the Market Rules and the Manual for Interconnection and Connection are updated, BESS facilities will be treated as load centers when they withdraw energy from the SEN and as power plants when they inject energy into it.

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At CCN, we have extensive experience in electricity sector regulations and transactions, and we would be pleased to assist clients in evaluating and implementing projects involving energy storage systems.