Solaria's 48.5 MW Battery in Burgos: Key Authorization Points for the Energy Sector

Key data

Solaria Promoción y Desarrollo Fotovoltaico, SLU, can begin construction of its battery storage module in Burgos after obtaining dual administrative authorization—prior and construction—published on November 9, 2026 in the BOE. The Resolution from the General Directorate of Energy Policy and Mines formalizes a project that combines solar generation and storage at a single connection point to the transmission grid.

This type of hybridization—photovoltaic plant plus battery—is one of the key vectors of Spanish energy policy for 2026 and beyond: it allows managing the intermittency of solar generation and providing flexibility to the electrical system without requiring new grid access points.

What does this regulation establish?

The resolution grants Solaria two simultaneous authorizations for the energy storage battery module called "Agrupación Maira Delta":

• Prior administrative authorization: recognizes the project's viability and enables the start of the construction process.
• Construction administrative authorization: allows the physical execution of works and installations.

The authorized technical infrastructure includes the following elements:

From an environmental perspective, the project passed the simplified environmental impact assessment with a favorable result, meaning it was not necessary to submit the project to the ordinary procedure—which is longer and more demanding. Nevertheless, the authorization incorporates corrective measures that are mandatory to comply with:

• Archaeological surveys in the action area.
• Faunal surveys to protect local biodiversity.
• Plantings of native species as a landscape integration measure.

Additionally, the Nuclear Safety Council (CSN) issued a favorable report with specific technical conditions that Solaria is obligated to comply with during the construction and operation of the module.

Economic and operational impact

The hybridization of a solar plant with a battery system of this scale has direct economic and operational consequences for the promoter and the electricity market:

• Revenue optimization: Solaria will be able to store energy generated during low-demand hours and inject it into the grid during peak hours, improving the average selling price of its electricity.
• Participation in adjustment services: a 48.5 MW battery has sufficient capacity to participate in balance and secondary regulation service markets managed by REE, opening an additional revenue stream beyond energy sales.
• Reduction of spillage: the battery allows absorbing photovoltaic generation that would otherwise be spilled (not injected into the grid due to technical constraints), improving the utilization factor of the 114.976 MW plant.
• Impact on the Castilla y León grid: the connection to the Barcina 400 kV REE substation strengthens the regional transmission grid's capacity to integrate more renewables.

For the sector, this project is a reference for how to legally structure solar-battery hybridization in Spain: simplified environmental assessment, dual simultaneous authorization, and transmission grid connection in a single procedure.

Who does it affect?

• Solaria Promoción y Desarrollo Fotovoltaico, SLU: direct promoter, with obligations to comply with environmental conditions and CSN requirements.
• Municipalities of Valluércanes and surrounding areas in Burgos: affected by construction works, archaeological surveys, and plantings of native species.
• Promoters of hybrid photovoltaic-battery projects in Spain: this case sets a precedent on the applicable procedure (simplified assessment, dual simultaneous authorization).
• Grid operators and REE: must manage the connection of the new module to the Barcina 400 kV substation and adapt transmission grid operation schemes in Castilla y León.
• Energy storage sector companies: manufacturers and installers of BESS (Battery Energy Storage Systems) with projects in process in Spain.
• Energy advisors and consultants: who support promoters in processing similar authorizations.

Practical example

A photovoltaic promoter who already has an operating plant—like Solaria's Agrupación Maira Delta of 114.976 MW—and wants to add battery storage can follow the same scheme as Solaria:

1. Request the prior administrative authorization and construction authorization simultaneously from the General Directorate of Energy Policy and Mines.
2. Size the battery in relation to the existing photovoltaic capacity: in this case, 48.50 MW of battery for 114.976 MW of solar represents a storage ratio of approximately 42% of installed photovoltaic capacity.
3. Design the evacuation infrastructure—in this case, underground lines at 30 kV and expansion of 220/30 kV substation—to connect with the already-granted transmission grid access point (SE Barcina 400 kV).
4. Undergo simplified environmental impact assessment, which in this project was favorable without needing the ordinary procedure, but with conditions (archaeological surveys, faunal surveys, and native plantings).
5. Obtain a favorable report from the Nuclear Safety Council with its specific technical conditions.

This scheme significantly reduces timelines compared to processing a new project from scratch, by leveraging the connection point and evacuation infrastructure already existing from the photovoltaic plant.

What should companies do now?

1. If you are Solaria or a promoter with similar authorization: review the CSN technical conditions and environmental corrective measures (archaeological surveys, faunal surveys, and native plantings) before starting works, as non-compliance can halt the project.
2. If you have an operating photovoltaic plant and are studying adding batteries: analyze whether your grid connection point allows hybridization without needing new access, as in the case of Agrupación Maira Delta with REE's SE Barcina 400 kV.
3. If you are an energy advisor or consultant: document the procedure followed in this case—simplified environmental assessment + dual simultaneous authorization—as a reference for hybrid projects of clients.
4. If you operate in the electricity market: note that the entry into operation of this 48.5 MW module in Castilla y León will increase the supply of flexibility and balance services in the area, with possible impact on intraday and adjustment market prices.
5. If you are a BESS systems manufacturer or installer: monitor the evolution of similar cases in process to anticipate demand for hybridization projects in Spain during 2026-2027.

Official source

Consult complete regulation at official source (BOE-A-2026-23496)

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-2026-23496