New transmission methodology for legacy contracts: updated rates applicable to permit holders

Summary Executive:

On June 18, 2026, the National Energy Commission (“CNE”) published in the Official Gazette of the Federation (“DOF") he "Agreement issuing the new methodology for determining the Transmission Service charges applicable to Permit Holders with interconnection contracts and transmission agreements entered into under the Public Electric Energy Service Law" (he "AgreementThe Agreement will enter into force on 19th October 2026 and replaces the methodology in force since 2010. A transitional exception period of up to two years is foreseen for those who initiate the voluntary migration procedure towards the figures of the new Electricity Sector Law.

Context and Basis

• The new methodology arises as a direct consequence of the constitutional reform regarding strategic areas and companies, published in the Official Gazette of the Federation on October 31, 2024, and the mandate contained in the Fourth Transitory Article of the Electricity Sector Law (“LSE”), which instructed the CNE to review and update transmission methodologies to reflect current conditions in the sector.
• The Agreement replaces Resolution No. RES/066/2010 and its amendment provided for in Resolution No. RES/194/2010, both issued by the now-defunct Energy Regulatory Commission, which established the "postage stamp" model for calculating transmission services applicable to renewable energy and efficient cogeneration power plants. The CNE determined that these methodologies were designed under circumstances and objectives that have already been achieved, including the target of 26% installed renewable capacity, met since 2014. Therefore, it is appropriate to update the criteria for determining the charges.

Scope and Obligated Parties

The Agreement is from mandatory compliance throughout the national territory and applies to two subjects:

• Permit holders: holders of a permit granted under the Public Electric Power Service Law who have an interconnection contract and transmission agreement entered into under said law.
• The supplier: the Federal Electricity Commission (“CFE“), as a state-owned public company responsible for providing the transmission service.

Determination of the Transmission Service Charge

The charge that the supplier must charge each permit holder is calculated as the sum of the amounts determined by the National Energy Control Center (“DINNER”) derived from market settlement, and integrates the following components:

The supplier must bill these charges monthly, in accordance with the interconnection agreement and the current transmission agreement. Additionally, the supplier must submit a monthly report of the charges collected to the CNE within ten business days following the last day of the reported month.

For permit holders with interconnection agreements for renewable energy or efficient cogeneration plants, the charges must also include the amounts derived from compensated energy, in accordance with clause fifteen of their respective agreements, until the Market Rules are updated. CFE Intermediación de Contratos Legados, SA de CV will be responsible for sending the corresponding data to CENACE.

Transitional Regime: Exception and Key Deadlines

The Agreement incorporates a favorable transitional regime for permit holders who decide to initiate the voluntary migration process to the LSE structures. The central elements of the transitional regime are presented below:

During the transitional exception period (October 2026 to October 2028), permit holders who meet the requirements of having contracts valid after October 6, 2028, and formally initiate the voluntary migration procedure, will continue to operate and pay according to the previous methodology.

The transitional benefit will cease early if the permit holder: (i) fails to complete all stages of the migration procedure; (ii) obtains authorized status in the physical asset registry; or (iii) begins operations in the MEM. In any of these cases, payment under the new Agreement will be due starting with the next billing period following the respective notification.

Interinstitutional Coordination

• The Ministry of Energy, the CNE, the CENACE and the CFE must coordinate to make the technical, operational and legal adjustments required to comply with the Agreement, within the scope of their respective competencies.

Key Points for Companies with Energy Projects

The Agreement represents a significant regulatory change for holders of generation permits subject to the legacy regime, particularly for renewable energy and efficient cogeneration projects. In this context, permit holders must review their interconnection agreements and transmission contracts to determine if their projects can benefit from the transitional regime established in the Agreement itself, as well as assess the advisability of initiating the voluntary migration procedure contemplated in Transitional Article Six of the Electricity Sector Law (LSE) before October 6, 2028.

Furthermore, given that the new methodology replaces the stamp duty scheme in place since 2010, it will be advisable to analyze its potential impacts on the cost structure, financial models, and commercial agreements associated with the projects.

Finally, considering the interpretive and operational challenges that could arise during the implementation of the Agreement, participants should closely monitor its practical application and promptly evaluate the regulatory, administrative or jurisdictional alternatives available in the face of any discrepancy related to the determination of the applicable charges or the scope of the transitional provisions.

Reference Links:

https://www.dof.gob.mx/nota_detalle.php?codigo=5790939&fecha=18/06/2026#gsc.tab=0