21 September 2026 • 18 minute read
Amendments to the Migration Guidelines of grandfathered electricity projects: Key considerations
Context and scope of the Amending Resolution
On September 8, 2026, the Federal Official Gazette (Diario Oficial de la Federación, or DOF) published the Resolution amending, eliminating, and adding various provisions of the Guidelines for the voluntary and expeditious migration of self-supply and cogeneration of electricity to the figures provided for in the Electricity Sector Law, or Acuerdo por el que se modifican, eliminan y adicionan diversas disposiciones de los Lineamientos para la migración voluntaria y expedita de autoabastecimiento y cogeneración de energía eléctrica a las figuras previstas en la Ley del Sector Eléctrico (Amending Resolution).
The Migration Guidelines were published in the DOF on June 18, 2026. For more information on the Migration Guidelines, read our previous client alert. On June 26, 2026, a clarifying note to the Migration Guidelines was published in the DOF, specifying the date of one of the applicable stages of the migration process.
The Amending Resolution entered into force on September 9, 2026. According to the Amending Resolution, the changes respond to requests from sector participants for additional time to carry out the corporate and contractual actions necessary to achieve migration, and extend the dates and deadlines originally established for the migration procedure.
The Amending Resolution also clarifies certain technical requirements, in light of the varying conditions under which Power Plants and Load Points (centros de carga) associated with Grandfathered Figures (Figuras Legadas) operate.
The following provides a summary of the amendments and key considerations.
Extension of the migration procedure deadlines
The Amending Resolution extends the deadlines in the migration calendars established in Articles 17 and 18 of the Migration Guidelines for the different migration modalities,[1] as shown in the following tables.
Calendar applicable to Modalities I, II, V, and VI: Migration of Power Plants and associated Load Points
| Stage | Original deadline | New deadline |
|---|---|---|
| First: Registration of expression of interest | June 19, 2026 – September 18, 2026 | June 19, 2026 – December 18, 2026 |
| Second: Submission of migration application | September 21, 2026 – October 16, 2026 | September 21, 2026 – January 15, 2027 |
| Third: Prevention, admission, or rejection | October 19, 2026 – December 24, 2026 | January 18, 2027 – March 26, 2027 |
| Fourth: National Energy Commission (Comisión Nacional de Energía, or CNE) resolution and permit | December 28, 2026 – February 12, 2027 | March 29, 2027 – May 14, 2027 |
| Fifth: Measurement Functionality review | October 19, 2026 – February 12, 2027 | January 18, 2027 – May 14, 2027 |
| Sixth: Pre-registration of physical assets | February 15, 2027 – March 5, 2027 | May 17, 2027 – June 4, 2027 |
| Seventh: Minimum Operating Tests | February 15, 2027 – April 30, 2027 for Measurement system and Dispatchable status; and October 1, 2027 – April 28, 2028 for Minimum Operating Tests | May 17, 2027 – August 17, 2028 for Measurement system and Dispatchable status; and October 1, 2027 – April 28, 2028 for Minimum Operating Tests |
| Eighth: Execution of contracts | August 16 – 31, 2028; September 4, 2028 – October 6, 2028 | August 18 – 31, 2028; September 4 – October 6, 2028 |
| Ninth: “Enabled” status and start of operation in the Wholesale Electricity Market (Mercado Eléctrico Mayorista, or MEM) | October 6, 2028 | October 6, 2028 |
Calendar applicable to Modalities III and IV: Migration of End Users to Qualified Supply or Basic Supply
| Stage | Original deadline | New deadline |
|---|---|---|
| First: Registration of expression of interest in the Migration Procedure | June 19, 2026 – September 18, 2026 | June 19, 2026 – December 18, 2026 |
| Second: Submission of the migration application | September 21, 2026 – October 16, 2026 | September 21, 2026 – January 15, 2027 |
| Third: Prevention – Review of applications and notification of prevention | October 19, 2026 – November 20, 2026 | January 18, 2027 – February 19, 2027 |
| Third: Cure – Cure of the notified prevention | November 23, 2026 – December 11, 2026 | February 22, 2027 – March 12, 2027 |
| Third: Admission – Admission, analysis, or rejection of the application | October 19, 2026 – December 24, 2026 | January 18, 2027 – March 26, 2027 |
| Fourth: CNE resolution on exclusion of Load Points and registration as Qualified Users | December 28, 2026 – February 12, 2027 | March 29, 2027 – May 14, 2027 |
| Fifth: Review and confirmation of Measurement Functionality of Load Points (parallel stage) | October 19, 2026 – February 12, 2027 | January 18, 2027 – May 14, 2027 |
| Sixth: Instruction – Instruction from the National Energy Control Center (Centro Nacional de Control de Energía, or CENACE) to the Federal Electricity Commission (Comisión Federal de Electricidad) to execute the connection contract and exclude Load Points from Grandfathered Contracts | February 15, 2027 – March 5, 2027 | May 17, 2027 – June 4, 2027 |
| Sixth: Execution – Execution of the connection contract and early termination of Grandfathered Contracts | March 8, 2027 – April 2, 2027 | June 7, 2027 – July 2, 2027 |
| Seventh: Registration of physical assets with “Enabled” status and notification to the Transmission Company or Distributor | April 5, 2027 – April 23, 2027 | July 5, 2027 – July 23, 2027 |
| Eighth: Compliance with Measurement System requirements (Article 5, section VI) | February 15, 2027 – August 15, 2028 | May 17, 2027 – August 17, 2028 |
Modernization Program
The Amending Resolution clarifies that, for Power Plants in operation to which up to 15 additional years of validity are granted (without exceeding 30 years in total), applicants must submit the Modernization Program evidencing the reliable operation of the Power Plant and, where applicable, the modernization actions, tests, or rehabilitation already carried out. The original text did not expressly contemplate the possibility of submitting actions already performed.
Early Minimum Operating Tests and entry into the MEM in 2027
With respect to the calendar for the migration of Power Plants and associated Load Points, the Amending Resolution permits Minimum Operating Tests[2] to be performed early. For this purpose, the applicant must propose the start date for the performance of such tests in the migration application, and CENACE must rule on the feasibility of such tests in the third stage.
Applicants who have registered an expression of interest may request CENACE to perform Minimum Operating Tests on a date other than that established in the calendar (the seventh stage, that is, from October 1, 2027, to April 28, 2028), subject to CENACE’s assessment.
The Amending Resolution adds a scenario for applicants who wish to enter into operation in the MEM before May 14, 2027. In that case, they must register the expression of interest and submit the migration application with a waiver of the calendar and the conclusion date of the Migration Period, as well as the applications for the procedures necessary to complete all stages of the process through “Enabled” status, for processing through ordinary channels.
Contractual relationship with the Market Participant
Where, as of the date of submission of the migration application, the contractual instrument with the Market Participant that will represent the Power Plant or the Load Points in the MEM has not yet been executed, the Amending Resolution provides that the Market Participant may be identified by submitting a letter of intent signed by the parties. If the letter of intent is not available, the Market Participant may be identified, and the applicant may state, under penalty of perjury, that the corresponding legal relationship is in the process of being executed.
Clarifications on measurement equipment
The Amending Resolution amends Article 44 to provide that Load Points with demand of less than one megawatt may migrate with existing measurement equipment, provided they comply with the Minimum Required Measurement Functionality, and may continue using such equipment after migration. In the event of a failure, they must restore at their own expense the minimum functionality pursuant to Article 57 of the Migration Guidelines. They remain subject to compliance with the Market Rules on Measurement Systems upon regulatory update or change of Market Participant following the conclusion of the Migration Procedure.
Through the addition of paragraphs to Article 45, the Amending Resolution establishes that when Power Plants or Load Points have Measurement System components that already comply with the Market Rules, they may continue using them during and after migration, without additional procedures and regardless of ownership, with any necessary adjustments permitted to comply with such rules. In the event of a failure, they must restore at their own expense the conditions pursuant to the regulations in force.
Shared substation
The Amending Resolution adds provisions to Article 56 for Load Points connected at shared substations. They may continue sharing the substation and receive Electricity Supply from different Suppliers through an agreement for the shared use of the substation. During the Migration Procedure, each Load Point within the private network on the low-voltage side of the transformer must be equipped with measurement equipment that complies with the Minimum Required Measurement Functionality. Once the procedure concludes, the Amending Resolution differentiates measurement obligations according to demand, depending on whether demand is less than, equal to, or greater than, one megawatt.
Load Points connected at the same substation must grant the Transmission Company or Distributor access to facilities, equipment, or Measurement Systems for the administration and acquisition of measurement records. The responsibility for the transfer of measurement records to CENACE corresponds to the Transmission Company when the Connection Point is on the National Transmission Network (Red Nacional de Transmisión), or to the Distributor when it is on the General Distribution Networks (Redes Generales de Distribución), applying a transformation loss factor of 2 percent, pursuant to the Measurement Manual for Settlements. The CENACE asset registry must associate Load Points with the voltage level of the Connection Point.
Grandfathered Figures expiring before March 29, 2027
The Amending Resolution amends the Tenth Transitory Article of the Migration Guidelines so that migration applications with respect to Grandfathered Figures with an expiration date prior to March 29, 2027 (previously December 28, 2026) are resolved under administrative simplification. CENACE must instruct the execution of the interconnection contract prior to the expiration date of the Grandfathered Contract.
Transitional regime and next steps
Permittees that had already registered an expression of interest or submitted a migration application prior to the publication of the Amending Resolution must confirm, within ten business days of its entry into force, through the Migration Window, their intention to continue with the procedure in accordance with the deadlines in effect at the time of their submission. If confirmation is not submitted within that period, the procedure is subject to the new calendar.
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[1] The applicable calendar for the Migration Procedure depends on the modality chosen pursuant to Article 15 of the Migration Guidelines, which provides for six modalities:
- Modality I applies to the migration of a Power Plant individually, and Modality II to the joint migration of a Power Plant and the Load Points associated with it, to operate in the MEM. Both modalities are governed by the nine-stage calendar of Article 17.
- Modality III allows End Users with Load Points whose demand is equal to or greater than one megawatt to migrate to obtain registration as Qualified Users and receive Qualified Supply. Modality IV applies to End Users who wish to maintain or receive Basic Supply. Both are governed by the calendar of Article 18; however, under Modality IV, the procedure is shorter: it concludes at the sixth stage and does not require the fifth, seventh, and eighth stages, which are specific to the MEM.
- Modalities V and VI regulate the joint migration of a Power Plant with local loads to self-consumption permits: interconnected under Modality V and isolated under Modality VI. Modality V follows the complete calendar of Article 17, while Modality VI comprises only the first through fourth stages.
[2] The Minimum Operating Tests are the following: 1) voltage range at the interconnection point; 2) reactive power capacity; 3) Volts/Hertz limiter; 4) reactive power capacity below maximum power; 5) frequency range; 6) primary frequency control; and 7) power quality requirements.