Herrera de los Navarros: New 21 MW solar plant must strengthen bird protection measures against existing wind turbines

The construction of a new photovoltaic plant in Herrera de los Navarros will be conditional on the adoption of additional measures to protect the birds and bats inhabiting the surrounding area. The Ministry for Ecological Transition published on Monday, November 2, the environmental impact statement for the project promoted by Sistemas Energéticos Barandón, which plans to install 37,472 solar panels over an area of 23.23 hectares.

The main requirement also affects the wind farm with which it will share electrical facilities: the company will have to review the wildlife mortality recorded in recent years and develop a joint plan to reduce collisions with the wind turbines. The resolution also includes measures to protect steppe habitats, conserve natural vegetation, and limit impacts during construction.

The project will be developed in the municipality of Herrera de los Navarros, located in the Campo de Daroca region, an area that already hosts a significant concentration of renewable energy production facilities.

The project proposes combining solar generation with that of the 35-megawatt Herrera de los Navarros wind farm, leveraging part of the existing electrical infrastructure. The future photovoltaic installation will have a capacity of 21 megawatts and will require a new underground transmission line to carry electricity to the shared evacuation system.

The environmental declaration, signed on October 19 by the Directorate General for Quality and Environmental Assessment and now published in the Official State Gazette, sets out the conditions that the project developer must meet to proceed with its administrative processing.

A plan to reduce bird and bat mortality at the wind farm

One of the most relevant aspects of the resolution is the obligation to jointly assess the effects of the new photovoltaic plant and the wind farm with which it will share infrastructure.

Before construction begins, Sistemas Energéticos Barandón must examine the results of the environmental monitoring of the Herrera de los Navarros wind farm corresponding, at a minimum, to the last two complete years available.

This analysis must identify which species have been affected, where the dead specimens were located, and which wind turbines present the highest collision risks.

It must also verify the effectiveness of the detection, deterrence, and selective shutdown devices already installed. These systems allow for the detection of the approach of certain species and automatically stop the machines when there is a risk of accident.

With all this information, the company must develop a joint plan for the prevention and reduction of bird and bat mortality, which will be submitted to the competent regional body in biodiversity.

The document must propose additional measures when necessary. Among the options outlined by the Ministry are expanding automatic shutdowns, modifying the activation thresholds of those systems, and establishing specific procedures for wind turbines that record higher issues.

This obligation responds to one of the main concerns associated with the concentration of renewable energy infrastructure: the cumulative effect that multiple facilities located in the same territory may have on wildlife.

Protecting steppe birds requires action beyond the solar plant

The environmental declaration also establishes measures aimed at compensating for land occupation and improving the living conditions of steppe birds.

The project developer must implement agri-environmental actions on an area equivalent to that occupied by the photovoltaic installation, namely approximately 23 hectares.

These actions must be located outside the solar panel enclosure, preferably on lands included in the Natura 2000 Network. The objective is to promote the conservation of species and improve their habitats without attracting them to areas where the risk of collision with wind turbines is highest.

The location of the measures will be agreed upon with the Directorate General for Natural Environment, Hunting and Fishing of the Government of Aragon, and the actions must be implemented before the project is executed.

The Ministry pays special attention to the location of elements that may attract wildlife, such as insect hotels. If environmental monitoring reveals that these devices increase the risk to sensitive species, they must be removed.

The documentation records the presence in the area of species of particular conservation interest, including the black kite, classified as endangered, and the bearded vulture, considered vulnerable.

Nesting sites for raptors such as the golden eagle, the short-toed eagle, and the griffon vulture have also been identified in the cliffs near the Huerva River. Field studies highlight the importance of the surrounding lands as feeding areas for various species.

The plant will occupy 23 hectares and will utilize the existing electrical evacuation infrastructure.

The project by Sistemas Energéticos Barandón plans to install 37,472 photovoltaic modules of 600 watts each, distributed across two enclosures and mounted on fixed structures.

The peak power will reach 22.5 megawatts, while the installed capacity will be 21 megawatts. The perimeter fence will have an approximate length of 2,634 meters.

The selected land is located north of the urban area of Herrera de los Navarros, in a predominantly agricultural zone. Access will be made through an existing path connected to the A-1101 road, which will avoid the need to open new, larger access routes.

The electricity generated will be transmitted via an underground 30-kilovolt line, 1,113 meters long, to a new sectioning center. From there, the existing evacuation line of the wind farm will be used to reach the Mata Alta substation.

The proposal is therefore configured as a hybridization of renewable energy facilities, combining solar and wind energy and sharing part of the infrastructure required for grid connection.

The Ministry has evaluated several alternative locations for the plant and different routes for the power line. The selected solution is the one that, according to the analysis presented by the developer, offers the least environmental impact among the options studied.

The resolution also includes conditions related to the conservation of soil and natural vegetation.

Although most of the area consists of agricultural land, within the project's scope there are small shrubland areas and three oak trees that must be preserved.

The developer will have to maintain the original terrain profile in the areas occupied by the solar panels and preferentially use structures driven directly into the ground, without concrete foundations.

To control vegetation growth, the Ministry favors sheep grazing, with a reference stocking rate of 0.2 large animal units per hectare.

The company must prepare a specific livestock management plan that will require the approval of the Government of Aragon. The conditions prohibit the permanent presence of a herd within the park and ban the use of herbicides and other chemical products that could disrupt wildlife.

These measures aim to reduce soil transformation and ensure that some of its natural functions are maintained during the plant's operation.

The project also includes environmental restoration actions, such as planting native vegetation and creating small groves to encourage the presence of pollinating insects.

Construction work must respect the breeding season of birds

The construction schedule will be conditioned by the periods of greatest sensitivity for wildlife.

The resolution establishes that construction work may not begin during the nesting period, which spans from March to July. It also limits maintenance activities during those months to urgent interventions only.

The aim is to avoid disturbances during the breeding of birds that use the area surrounding the facility, particularly those species that face the greatest conservation challenges.

Environmental monitoring will continue during the operation of the plant and will cover both the solar panels and the wind farm in a coordinated manner.

The controls must enable the detection of any changes in the behavior of birds and bats, the identification of new risk situations, and the modification of protective measures when the results so advise.

The document also requires the designation of a person responsible for overseeing compliance with environmental obligations and coordinating actions with the competent authorities.

Protection of the Valdealjibe ravine and archaeological monitoring

The proximity of the Valdealjibe ravine introduces additional obligations related to water protection and land conservation.

The Ebro River Basin Authority has authorized the planned works within its police zone, although the project’s development must comply with the conditions set by the river basin agency.

Among the required measures are ensuring adequate drainage, avoiding significant alterations to the natural flow of water, and preventing discharges that could affect both surface and groundwater.

The works will also be subject to archaeological monitoring during earthworks. If heritage-related remains are found, construction must be halted in the affected area, and the discovery must be reported to the Directorate General for Cultural Heritage of the Government of Aragon.

These conditions are added to the measures for restoring land temporarily affected by the works and the obligation to properly manage waste and materials used in construction.

A territory with a high concentration of renewable energy facilities

The environmental assessment also examines the cumulative effects of the solar plant in conjunction with existing energy infrastructure within a ten-kilometer radius.

The study identifies 31 wind farms in that area, comprising 329 wind turbines with a combined capacity of 1,274.8 megawatts, including facilities that are operational, authorized, or in the permitting process.

Of this total, 22 wind farms are operational, featuring 255 wind turbines and 876 megawatts of capacity. This is supplemented by two authorized wind farms and another seven that are at various stages of administrative processing.

The documentation also records several photovoltaic installations, power lines, and substations, highlighting the energy transformation experienced by this area of the Campo de Daroca and its surroundings.

The concentration of projects makes it particularly important to monitor their effects on birds, vegetation, landscape, and traditional land uses.

The environmental study considers that the cumulative effects on wildlife are of moderate intensity, while acknowledging differences across various areas based on infrastructure density, habitat types, and land use.

An environmental declaration that sets the conditions for the continuation of the project

The resolution published on Monday in the Official State Gazette (BOE) marks a step forward in the administrative processing of the Herrera de los Navarros photovoltaic plant, which began its environmental assessment in 2023 and moved to the ordinary procedure during 2024.

The Ministry has now set the conditions that must be incorporated into the project before its approval. The developer will have to technically define the preventive, corrective, and compensatory measures, include their budget, and complete the necessary sectoral authorizations to execute the facilities.

The future solar plant will combine its production with that of the existing 35-megawatt wind farm, but the connection between the two installations will also entail shared environmental monitoring.

The main novelty of the resolution lies precisely in this requirement: the addition of new solar capacity necessitates a review of the wind farm’s operation and its effects on birds and bats.

Herrera de los Navarros is thus facing a new renewable energy project in an area where such facilities already have a considerable presence. Its development will be linked to the implementation of a set of measures aimed at reconciling electricity production with the protection of wildlife, natural habitats, and the environmental resources of the Campo de Daroca.