Synchronous Compensator in Belinchón: What It Means for the Electrical Grid in 2026

Key data

Spain's electrical transmission network takes a concrete step toward greater stability: the General Directorate of Energy Policy and Mines has granted Red Eléctrica de España, SAU, the prior administrative authorization and administrative construction authorization to expand the Belinchón substation (Cuenca). The resolution, published on June 20, 2026, enables the equipment of an existing reserve position with a synchronous compensator in the 400 kV park.

This action is included in the Transmission Network Development Plan 2021-2026, approved by the Council of Ministers in July 2025, placing it within the country's official roadmap for critical electrical infrastructure.

What does this regulation establish?

The resolution grants two simultaneous authorizations to Red Eléctrica de España, SAU:

• Prior administrative authorization: confirms the viability of the project from the perspective of energy planning.
• Administrative construction authorization: allows the initiation of equipment installation works.

The action consists of equipping an existing reserve position at the Belinchón substation with a synchronous compensator. This type of equipment provides mechanical inertia to the electrical system, a resource that becomes increasingly scarce as renewable generation (solar and wind) grows, which lacks natural inertia.

The urgent nature of the action allowed administrative timelines to be cut in half compared to the ordinary procedure. Furthermore, as it is located in a substation already in service, it was excluded from the environmental impact assessment process. No objections were received during the public information period, and none of the consulted bodies showed opposition.

Economic and operational impact

For the electricity sector and large industrial consumers, this authorization has direct implications for supply quality and security:

• Greater frequency stability: the 250 MVA synchronous compensator provides mechanical inertia to the system, reducing the rate of frequency variation in the event of disturbances. This is especially relevant in scenarios of high renewable penetration.
• Transmission network resilience: the installation improves the network's capacity to absorb imbalances between generation and demand without affecting supply.
• No direct cost for companies other than REE: investment and operation are the sole responsibility of Red Eléctrica de España, SAU, as the transmission network operator. It generates no direct economic obligations for third parties.
• Impact on system costs: investments in transmission infrastructure are recovered through network access tariffs, so in the long term they may have a marginal influence on electricity system rates.

Who does it affect?

• Red Eléctrica de España, SAU: holder of the authorization and responsible for executing and operating the installation.
• National electricity system operators: benefit from greater stability and response capacity to disturbances in the transmission network.
• Renewable energy generators (solar and wind) connected to the transmission network in the central zone: additional inertia facilitates the integration of their variable production.
• Large industrial consumers connected to the 400 kV network: indirect improvement in electricity supply quality.
• General State Administration: the General Directorate of Energy Policy and Mines exercises regulatory oversight of the installation.

Practical example

Imagine a large-scale solar park connected to the transmission network in the Cuenca area. In a scenario of high solar generation and low demand, a sudden disturbance (such as the disconnection of a line) can cause an abrupt frequency drop in the system. Without sufficient inertia, the system has less time to react before protection mechanisms disconnect facilities.

With the 250 MVA synchronous compensator with 6 seconds of inertia installed in Belinchón, the system has more reaction time to that disturbance. This reduces the risk of cascading disconnections and improves supply security for all consumers connected to that area of the 400 kV network, without the solar park or industrial consumers needing to make any additional investment.

What should companies do now?

1. Verify if you are an affected electricity sector agent: if your company operates as a generator, distributor, or large consumer connected to the transmission network in the Cuenca area or electrically linked zones, review how this infrastructure improvement may affect your access contracts and supply conditions.
2. Follow the progress of the Transmission Network Development Plan 2021-2026: this resolution is one of the actions in the plan approved by the Council of Ministers in July 2025. Identify if there are other planned actions that may affect your connection area or assets.
3. Evaluate the impact on renewable connection strategies: if you have renewable generation projects pending connection to the transmission network, the stability improvement in the area may influence access and connection studies.
4. Consult the complete resolution in the BOE: to learn the exact technical and administrative conditions of the authorization, access the full text at BOE-A-2026-13453.

Official source

View complete regulation in official source

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-2026-13453