Red Eléctrica, the Redeia subsidiary responsible for the transmission and operation of the Spanish electricity system, is progressing with the construction of the battery storage system next to the existing Sant Antoni substation (Ibiza). The progress was reviewed today during a site visit by the Secretary of State for Energy, Joan Groizard, and the Chairwoman of Redeia, Beatriz Corredor.

As the Chairwoman of Redeia explained, the batteries, which will be fully integrated into the transmission grid, will maximise the contribution of the electricity links on Illes Balears, particularly the Mallorca–Ibiza  interconnector. This will make it possible for Ibiza to cover 100% of its demand for much of the year, up from the current annual average of 65%.

In this regard, Corredor highlighted that these batteries, together with those being installed in Menorca, will form “the largest system of its kind – battery storage fully integrated into the transmission grid – in southern Europe, and the first to be installed in Spain. The project is being carried out in close collaboration with the local community, institutions and residents, following a process of engagement and dialogue to ensure social integration and environmental protection.”

The Secretary of State for Energy noted that “this is one of the most important energy storage facilities in Spain, beyond the Islas Baleares themselves, which are a key focus of Spain’s current Electricity Planning and receive the largest budget allocation of any autonomous community. These batteries are proof of the Government’s commitment to advancing the islands’ energy transition.”

This new project in Ibiza involves the installation of a battery storage system with a total capacity of 90 MW and 67.5 MWh. The construction of the batteries, currently in the electromechanical assembly phase, has also required the expansion of the 66 kV Sant Antoni substation, to which they will be connected. This will serve as a strategic point in Ibiza’s electricity system, strengthening the island’s energy flows. 

With the batteries fully integrated into the transmission grid, and under the current system conditions on each island (including demand, conventional and renewable energy generation, self-consumption, etc.), the contribution of the current Mallorca–Ibiza link will be almost doubled, increasing from 100 MW to around 190 MW. This will bring associated benefits in terms of improved system efficiency and reduced CO₂ emissions. 

The Sant Antoni batteries, like those being built in Es Mercadal (Menorca), are pioneering infrastructure within the transmission grid, the first of their kind included in an electricity planning framework. The investment in the Sant Antoni batteries amounts to €77 million and is included in the list of projects eligible for funding from the European Union’s NextGenerationEU – Recovery, Transformation and Resilience Plan.

From a visual perspective, the battery system consists primarily of a set of cells with all equipment housed in modular containers, complying with all safety guarantees and environmental control requirements. The installation of the batteries is expected to be completed in summer. This will be followed by a pre-operational and testing phase prior to their final entry into service, in line with the current Electricity Transmission Grid Development Plan. 

The Sant Antoni batteries, like those in Es Mercadal in Menorca, will feature cutting-edge technology through a dedicated communication system called HERMES, which connects them to the rest of the grid. This system will enable real-time monitoring of the condition and measurements of the links, providing robust communication capable of detecting contingencies and enabling automated response mechanisms.

Environmental commitment: protecting the sargantanes

For the first time in a project of this nature, the development of the Sant Antoni battery infrastructure includes a project to protect the Pitiüsa wall lizard (known as sargantana or Podarcis pityusensis), carried out jointly by Redeia and Ibiza Preservation. 

Prior to the start of earthworks and civil engineering works, a specific survey was carried out to locate sargantanes in the area, and a census of specimens within the project zone was prepared. 

In parallel, a shelter has been built to ensure the protection of the sargantanes on land adjacent to the substation. It is enclosed with a synthetic material that prevents snakes from entering and is subject to regular monitoring and inspection. This initiative reflects Redeia’s commitment to the communities where it develops infrastructure through projects that deliver environmental and social value, within the framework of its Comprehensive Impact Strategy.

Latest investments in the Pitiüses

The Sant Antoni batteries are the latest in a series of investments recently made by Red Eléctrica in new electricity infrastructure for the transmission grid of the Pitiüses, in line with the current electricity planning framework.

The battery system builds on the commissioning of the new interconnection between Ibiza and Formentera in 2023, which has enabled 100% of electricity demand on the smaller of the Pitiüses to be met via the interconnection and allowed the closure of the Es Ca Marí thermal power plant. The investment amounted to €96 million.

In addition, a new 132 kV underground line between the Ibiza and Bossa substations entered into service in 2025, which, together with the new Sant Jordi 132 kV substation and other line reinforcement or voltage upgrade works, forms part of the so-called Southern Axis. This is a set of transmission grid projects in Ibiza that are key to strengthening the island’s security of supply and quality of service.

The Southern Axis infrastructure – representing an investment of €35 million – is a more sustainable alternative to the former Es Fornàs project. While it has an equivalent electrical performance, it avoids the construction of a double overhead line crossing the island from east to west and the need for a new 132 kV outdoor substation in Sant Antoni.