Electricity Remuneration 2027: adjustment for fiber optic in regulated networks

Key data

Electricity transport and distribution companies that have deployed fiber optic along their regulated networks and use it to provide telecommunications services or other commercial activities see their regulated remuneration reduced in 2027. The Resolution of October 23, 2026 from the CNMC sets the specific adjustment applicable to the 2027 fiscal year, following the methodology approved in January 2024 and modified in September 2025.

The regulatory logic is clear: if an asset financed by regulated remuneration—and therefore indirectly paid by consumers—generates income in unregulated markets, that benefit must be returned to the system. The resolution materializes this principle in a specific reduction in the annual remuneration of each affected company.

What does this regulation establish?

The resolution establishes the amount of the remuneration adjustment that each affected company must assume in 2027 as a consequence of using its fiber optic—installed in regulated networks—for activities other than the distribution or transport of electrical energy.

The calculation of the adjustment incorporates two types of costs:

• Direct costs: those directly attributable to the fiber optic used in unregulated activities.
• Indirect costs: shared costs that the regulated infrastructure bears by also hosting commercial use.

The unit reference values used in the calculation are those established in the CNMC Circular 7/2025, which updated the parameters applicable to this type of adjustment.

The base methodology was approved in January 2024 and subsequently modified in September 2025, which means that the calculation framework has been maturing for two fiscal years before being applied to the 2027 fiscal year.

Economic and operational impact

The direct impact is a reduction in regulated remuneration that each affected company will receive in 2027. This reduction is not a penalty: it is a regulatory neutrality mechanism that prevents the unregulated business from being subsidized by the electrical system.

From an operational perspective, affected companies must:

• Have correctly identified and accounted for the sections of fiber optic used in unregulated activities.
• Apply the unit values from Circular 7/2025 to verify that the adjustment calculated by the CNMC is correct.
• Incorporate the reduction in their financial projections for the 2027 fiscal year.

For companies that do not use their fiber optic in commercial activities other than regulated distribution, the resolution has no economic impact. For those that do, the adjustment reduces the guaranteed regulated income for the year, which may affect investment planning and the profit and loss account of the regulated business.

Who does it affect?

The resolution distinguishes with precision between companies subject to the adjustment and exempt companies:

Subject to remuneration adjustment:

• The electricity transport company (Red Eléctrica de España / REE), as it has fiber optic in its transport network and uses it in different activities.
• Distributors with more than 100,000 customers that use fiber optic installed in their regulated networks for different commercial activities.
• Distributors with more than 100 km of fiber optic infrastructure, regardless of the number of customers.

Exempt from the adjustment:

• Small distributors that do not exceed either of the two previous thresholds (neither 100,000 customers nor 100 km of fiber optic in regulated network).

Practical example

An electricity distributor with more than 100,000 customers that has deployed fiber optic along its distribution network and leases it to a telecommunications operator to provide internet services is, by definition, using a regulated asset in an unregulated business.

Under this resolution, the CNMC calculates the adjustment by applying the unit values from Circular 7/2025 to the direct and indirect costs attributable to that commercial use. The result is a specific reduction in the regulated remuneration that distributor will receive in 2027.

If that same company had not correctly reported to the CNMC the volume of fiber optic used in different activities, the adjustment might not reflect reality, with the consequent regulatory risk in subsequent fiscal years. Correct separate accounting of assets is, therefore, the first line of defense.

What should companies do now?

1. Verify if you are subject to the adjustment: check if your company exceeds the thresholds of 100,000 customers or 100 km of fiber optic infrastructure in regulated network. If you do not exceed them, the resolution does not affect you.
2. Review the regulatory accounting of fiber optic: ensure that the sections of fiber used in unregulated activities are correctly identified and separately accounted for from those used in regulated activity.
3. Apply the unit values from Circular 7/2025: verify that the adjustment calculated by the CNMC for your company is consistent with the direct and indirect costs that correspond according to the current methodology.
4. Incorporate the reduction in the 2027 budget: adjust the financial projections of the regulated business to reflect the reduction in remuneration that will enter into force on January 1, 2027.
5. Consult with the regulatory team: if there are discrepancies between the adjustment calculated by the CNMC and the one resulting from your own accounting, now is the time to review it before the 2027 fiscal year begins.

Official source

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Disclaimer: This article is for informational purposes only and does not constitute legal advice. For specific decisions, consult a qualified professional. Source: https://www.boe.es/diario_boe/txt.php?id=BOE-A-2026-23261