Solar hybridization + 21.69 MW battery storage in Cuenca: keys for the energy sector

Key data

The FV Bañuela solar plant, with 49.7 MW of installed capacity in Altarejos (Cuenca), takes a decisive step toward energy manageability: the General Directorate of Energy Policy and Mines has granted GR Bañuela Renovables, SLU prior administrative authorization and administrative construction authorization to add a battery storage module of 21.69 MW. The resolution, published in the BOE on August 17, 2026 with reference BOE-A-2026-17875, consolidates Spain's commitment to renewable hybridization with storage as a lever to reduce solar intermittency.

The resulting hybrid installation will operate with 50 MW of installed capacity and will require new evacuation infrastructure: a 30 kV line to the existing substation.

What does this regulation establish?

The resolution grants two simultaneous authorizations to promoter GR Bañuela Renovables, SLU:

• Prior administrative authorization: enables the promoter to develop the hybridization project.
• Administrative construction authorization: allows the start of works on the storage module and its evacuation infrastructure.

The project passed the simplified environmental impact assessment, but with conditions that the promoter must comply with mandatorily. These conditions are articulated at two distinct moments in the project cycle:

The evacuation infrastructure consists of a new 30 kV line that will connect the storage module with the already existing substation, thus minimizing impact on the territory.

Economic and operational impact

Hybridization with storage radically transforms the business model of a solar plant. A pure photovoltaic installation sells energy only when there is solar radiation, which exposes it to low prices during peak generation hours. By incorporating 21.69 MW of storage, FV Bañuela will be able to:

• Shift energy delivery to time slots with higher prices in the wholesale market.
• Participate in system adjustment services (frequency regulation, reserves).
• Improve its generation profile, increasing the average value of the MWh sold.
• Reduce energy spillage during network saturation hours.

From an operational perspective, the promoter assumes additional costs derived from environmental conditions: permeable fencing design, contracting botanical surveys, preparation of the integrated environmental monitoring plan and self-protection plan. These documents must be ready at different times (before works and before commissioning, respectively), which requires careful planning of the execution schedule.

Who does it affect?

• GR Bañuela Renovables, SLU: direct promoter, holder of all obligations and conditions of the resolution.
• Castilla-La Mancha Administration: competent in environmental and urban supervision of the project.
• Municipality of Altarejos (Cuenca): affected by the new evacuation infrastructure and land use.
• Network operators and REE: must integrate the new hybrid capacity into the 30 kV network planning.
• Promoters of other solar plants in Spain: this resolution is a relevant precedent on environmental conditions required in similar hybridization projects.
• Consulting and energy engineering firms: must know the documentary requirements (monitoring plans, self-protection, botanical surveys) to correctly advise their clients.

Practical example

GR Bañuela Renovables currently has the FV Bañuela plant operating with 49.7 MW. Without storage, all generated energy must be injected into the grid at the moment of production, which during peak solar hours can coincide with low prices due to excess renewable supply.

With the 21.69 MW battery module authorized, the company will be able to charge the batteries during peak radiation hours (and low prices) and discharge them during peak demand hours (evening-night), when the wholesale market price is significantly higher. Additionally, the 50 MW hybrid installation will be able to access system operator adjustment service markets, an additional revenue source unavailable to purely photovoltaic plants without storage.

To reach that point, the project team must complete the integrated environmental monitoring plan before the start of works and conduct prior botanical surveys. Before commissioning, it must have the self-protection plan approved. Omitting any of these steps could halt the work or prevent grid connection.

What should companies do now?

1. If you are GR Bañuela Renovables: immediately commission the botanical surveys and integrated environmental monitoring plan, as they are a prerequisite for the start of works. Do not start construction without having them submitted.
2. If you are a promoter of another solar plant with a hybridization project: use this resolution as a reference for the environmental conditions that the General Directorate of Energy Policy and Mines is requiring (permeable fencing, herbicide prohibition, botanical surveys, integrated monitoring plan, self-protection plan).
3. If you are an energy consultant or engineer: update your technical documentation templates to include the five environmental conditions identified in this resolution. They are already a de facto standard in storage hybridizations.
4. If you are an investor or financier of renewable projects: verify that the execution schedule of the project in which you participate contemplates the documentary milestones prior to the start of works and commissioning. A delay in these documents can halt the project and affect expected returns.
5. If you operate in the regulatory environment of Cuenca or Castilla-La Mancha: review whether the new 30 kV line and existing substation require coordination with your own installations or network plans.

Official source

Consult complete regulation at 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-2026-17875