Power week, 14–21 September: a deadline that did not move, unannounced audits, and batteries that already pay

Corriente BESS · Weekly briefing for investors · 21 September 2026

Two items this week set dates or obligations, and several confirm a trend: Mexico’s grid remains short where demand is growing fastest, and that gives storage its value. The rest of the flow is about money (how much will be invested and who can execute it) and about the fiscal cost of holding down the price of diesel.

What sets the rules

Legacy permits: the migration window was extended, the grace period was not. On 8 September, Sener extended the deadlines in the guidelines under which self-supply and cogeneration permits migrate to the Electricity Sector Law. The cut-off for filing the application moved from 16 October 2026 to 15 January 2027. According to Energía a Debate, the two-year grace period during which the new transmission tariffs do not apply was not adjusted. It still runs from 19 October 2026 to 6 October 2028.

In practice, anyone who wants the full benefit cannot treat 15 January as the reference date. They have to act before 19 October. The column reports permit holders rushing their filings and others that have given up on migrating. Whether Sener corrects the discrepancy remains to be seen. In the meantime, any load centre with a legacy contract carries a calendar risk.

Fuel stations and terminals: unannounced audits. The regulation to the Quality Infrastructure Law was published in the Official Gazette (DOF) on 4 September and has been in force since the 7th. It allows standards authorities to inspect service stations, storage terminals and distributors without a prior complaint. It also requires volume and quality measurement systems to have calibration traceable to the national system of units. An inconsistency can end in temporary suspension or penalties. This adds to regulatory pressure the segment already faced: self-consumption registration with the CNE closes on 31 December, and volumetric-control verification is now conducted on site.

Storage: the thesis holds up on facts

Actis comes in with batteries from day one. The London-based fund launched Yeltica Energy, a greenfield platform targeting more than 2 GW in Mexico. It starts with three solar-plus-storage projects awarded in CFE’s first mixed-scheme tender. Together they add up to roughly 330 MWp of PV and 255 MWh of batteries, with 25-year dollar-denominated, inflation-indexed PPAs and CFE as anchor offtaker. It is one of the first concrete signals of how mixed-scheme projects get financed: long-term contracted cash flows, in hard currency, with storage inside the project from the outset.

The south-east blackout as a business case. Between 1 and 3 September, more than 745,000 customers in Yucatán, Quintana Roo, Campeche and Chiapas lost power. Quartux reports that its storage systems on the peninsula, over 100 MW/MWh, restored operations at industrial and tourism sites in under 10 minutes, while the grid took hours to recover. These are the company’s own figures, but they illustrate the resilience argument, which in industry and tourism weighs as much as tariff savings.

Why the peninsula keeps failing. A column in Energía a Debate sums it up: the system is designed to the N-1 criterion (withstand the loss of one component), but in Baja California, Baja California Sur and Yucatán–Quintana Roo, demand grew faster than local generation and the grid. CFE’s responses this week confirm the diagnosis:

• BCS: 128 MW of mobile gas turbines and about MXN 2.7 billion for transmission, distribution and electrification.
• Cozumel: the Playacar–Chankanaab II submarine line, at MXN 3.56 billion, with two substations and two 115 kV lines. Works start on 5 October.

These are fixes that take years or burn expensive fuel, exactly the gap where storage competes best.

Money and execution capacity

MXN 5.7 trillion in public and mixed investment between 2026 and 2030, according to the infrastructure plan in the 2027 Economic Package. 54.15% goes to energy, more than rail (15.63%) and roads (13.94%) combined.

Fitch warns that the challenge is not financing but execution: permits, construction capacity and cost control.

Clean-energy certification: CFE’s LAPEM asked the CNE to accredit it to certify clean power plants and measure the share of fuel-free energy in the Wholesale Electricity Market. If approved, CFE would be both the dominant generator and the verifier, a possible conflict of interest for private players.

Hydrogen: Mexico has identified 31 clean-hydrogen projects worth USD 22.37 billion. The pipeline is still at an early stage.

Fuels: the cost of holding the price

Diesel has decoupled from crude and trades near USD 200 per barrel. Three effects:

• In the power market: peaking plants that use diesel as primary or backup fuel can push the Local Marginal Price far higher than their share of generation would suggest.
• In public finances: IMEF estimates that IEPS fuel subsidies cost MXN 47.3 billion from January to July. In 2025 they were not needed.
• On the MXN 27 cap: keeping it could cost up to MXN 50 billion a month, according to Grupo Caraiva.

In Guanajuato, federal and state authorities seized 59 million litres of allegedly illicit fuel at the Gas Natural del Noroeste (Grupo SIMSA) terminal in San José Iturbide. The company maintains that all its permits are in order.

Dates to watch

Date	What happens
5 Oct 2026	Works begin on the submarine line to Cozumel
19 Oct 2026	Transmission-tariff grace period starts for migrating legacy permits
9 Nov 2026	Sener notifies the permits approved by the CNE under the Second Call for strategic projects
31 Dec 2026	Deadline to register fuel self-consumption facilities with the CNE
15 Jan 2027	Legacy-permit migration filings close (extended deadline)

The read

The week reinforces three ideas:

1. Storage is now part of the base project. CFE’s mixed-scheme projects include it from the design stage.
2. Resilience is as strong a selling point as the tariff. Especially in regions with a weak grid.
3. Near-term regulatory risk sits in the calendar, not in the direction of policy. A deadline that did not move can change the economics of a legacy contract.

This briefing is for information only and does not constitute investment advice.

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Sources: Energía a Debate — Legados: una pequeña omisión de fechas · Energy21 — Gasolineras bajo la lupa; inician auditorías de oficio · Energía a Debate — Actis lanza Yeltica Energy · Energy21 — Apagón en el sureste afectó a 745 mil usuarios · Energía a Debate — La razón de los apagones o el N-½N · Energy21 — CFE suma 128 MW en BCS · Energy21 — CFE mete 2,700 mdp a la red de BCS · Energía a Debate — Línea de transmisión a Cozumel · Energy21 — Energía captará 54% del plan de infraestructura · Energy21 — Fitch ve riesgo de ejecución · Energy21 — CFE busca aval para certificar energías limpias · Energy21 — Hidrógeno limpio perfila inversión por US$22,370 millones · Energía a Debate — El impacto del diésel en el MEM · Energía a Debate — Descuentos al IEPS generan merma de 47,300 mdp · Energy21 — Mantener el diésel en 27 pesos costaría hasta 50 mil mdp al mes · Energy21 — Aseguran 59 millones de litros en Guanajuato