Key data
| Regulation | Resolution of 21 October 2026, from CNMC — summons in administrative contentious proceedings 4/991/2026 |
|---|---|
| BOE Publication | 30 October 2026 |
| Entry into force | Not specified |
| Appellant | Bahía de Bizkaia Electricidad, SL |
| Judicial body | National Court |
| Challenged resolution | CNMC Resolution on calculation, supervision and valuation of loss balances in the gas system — gas year 2025 |
| Deadline to appear | 9 days from publication in the BOE (from 30 October 2026) |
| Affected parties | Gas system facility operators and energy sector operators |
| Category | Energy |
| Exercise | Gas year 2025 |
Gas system facility operators in Spain face a very narrow window of time to protect their economic position. The CNMC has published in the BOE the summons for the administrative contentious proceedings 4/991/2026, filed by Bahía de Bizkaia Electricidad, SL before the National Court against the resolution that regulates the calculation and valuation of loss balances for gas year 2025 and its effect on the compensation of facility operators.
Any company operating facilities in the gas system that believes the outcome of this litigation could affect its regulated income should urgently assess whether to appear in the proceedings as a defendant.
What does this regulation establish?
The challenged CNMC resolution regulates three key aspects of the gas system for gas year 2025:
- Calculation of loss balances: determines how gas losses occurring in transport and distribution through networks are quantified.
- Supervision and valuation: establishes the criteria for economically valuing those losses and monitoring their evolution.
- Effect on compensation: links the result of loss calculation with the regulated compensation received by gas facility operators.
Bahía de Bizkaia Electricidad, SL considers this resolution to be contrary to law and has challenged it before the National Court. The CNMC, as the body that issued the resolution, publishes the summons so that any third party with legitimate interest can appear in the proceedings and defend their position.
The mechanism is the usual one in Spanish administrative contentious proceedings: when a regulatory resolution is challenged, other operators who benefit from that resolution (or who could be harmed if it is annulled) have the right to appear as defendants to defend their interests alongside the Administration.
Economic and operational impact
The economic impact of this challenge depends directly on what the National Court decides. There are two possible scenarios:
| Scenario | Consequence for facility operators |
|---|---|
| The court dismisses the challenge | The CNMC resolution is maintained. The loss calculation criteria and associated compensation do not change for gas year 2025. |
| The court upholds the challenge (wholly or partially) | The CNMC must recalculate loss balances with new criteria. This can alter —up or down— the regulated compensation of affected facility operators. |
The risk for operators who do not appear is that the proceedings are resolved without them being able to defend their position, and that a potentially favorable judgment modifies the compensation criteria without them having had a voice in the proceedings.
From an operational perspective, judicial uncertainty about loss criteria can also hinder financial planning for gas operators in the current and following years, since regulated compensation is a central component of their income.
Who does it affect?
- Gas system facility operators: companies owning transport networks, distribution networks, regasification plants, underground storage or other infrastructure of the Spanish gas system.
- Energy sector operators with regulated compensation linked to loss calculation for gas year 2025.
- Companies with legitimate interest in maintaining or modifying the loss calculation criteria established by the CNMC.
- Legal and financial advisors of gas sector companies who must assess the regulatory risk of their clients.
Practical example
A natural gas distribution company, operator of a distribution network in several provinces, receives annual regulated compensation calculated in part based on loss balances recognized by the CNMC for gas year 2025.
If the National Court upholds the challenge filed by Bahía de Bizkaia Electricidad and requires the CNMC to recalculate those balances with different criteria, this distributor's compensation could be modified —even retroactively for gas year 2025— without the company having had the opportunity to defend before the court the validity of the original resolution.
If this distributor had appeared as a defendant within the 9-day deadline from 30 October 2026, it would have been able to present its own arguments and evidence to support the CNMC resolution. By not doing so, it is excluded from the proceedings and must accept the result dictated by the court.
What should companies do now?
- Verify if you are a gas system facility operator with regulated compensation linked to loss calculation for gas year 2025. If so, this challenge directly affects you.
- Calculate the potential economic impact of a possible modification of loss criteria on your regulated compensation. The greater the exposure, the more justified the appearance in the proceedings.
- Consult with legal advisors specialized in regulatory energy law before the 9-day deadline from 30 October 2026 expires to decide whether to appear as a defendant in proceedings 4/991/2026 before the National Court.
- Prepare the necessary documentation for appearance if you decide to act: power of attorney, proof of facility operator status and justification of legitimate interest.
- Monitor the judicial proceedings even if you do not appear, to anticipate possible changes in compensation criteria and plan financially accordingly.
Frequently asked questions
What is administrative contentious proceedings 4/991/2026 on gas losses?
It is the challenge filed by Bahía de Bizkaia Electricidad, SL before the National Court against the CNMC resolution that regulates the calculation, supervision and valuation of loss balances in the gas system for gas year 2025 and its effect on the compensation of facility operators. The CNMC published the summons in the BOE on 30 October 2026.
How much time do I have to appear in the proceedings on gas losses 2025?
The deadline is 9 days from publication of the summons in the BOE, which took place on 30 October 2026. After that deadline, it is not possible to join the proceedings as a defendant. It is recommended to consult with specialized legal advisors with the utmost urgency.
What happens if I do not appear in the challenge and the court changes the loss criteria?
If the court upholds the challenge filed by Bahía de Bizkaia Electricidad and modifies the loss calculation criteria, the CNMC must recalculate the balances for gas year 2025. This can alter the regulated compensation of gas facility operators, up or down, without operators who did not appear having been able to defend their position in the proceedings.
What are losses in the gas system and why do they affect compensation?
Losses are gas losses that occur during transport and distribution through networks. The CNMC calculates and values these balances annually for the corresponding gas year. The result of that calculation directly affects the regulated compensation received by gas facility operators, as it forms part of the parameters that determine their recognized income.
Where can I consult the official summons for the proceedings on gas losses 2025?
The summons is published in the Official State Gazette with reference BOE-A-2026-22786, with publication date of 30 October 2026. You can consult it directly on the BOE website: https://www.boe.es/diario_boe/txt.php?id=BOE-A-2026-22786.
Official source
Consult complete regulation in official source
Notice: 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-2026-22786
