Tera Batteries is commissioning CATL cabinets at two Balearic Islands substations, moving a 140 MW/105 MWh grid storage project into its final phase.
Spanish grid operator Red Eléctrica developed the project, integrating battery systems into the transmission network at substations in Mercadal, Menorca, and San Antonio, Ibiza. Combined, the two make up the largest Storage as Transmission Asset (SATA) system in southern Europe and the first of its kind in Spain, said Red Eléctrica.
Tera Batteries is commissioning and verifying equipment to ensure the system meets technical specifications ahead of grid integration. The company told pv magazine the project “is in its final phase of execution, assembly and commissioning,” with completion expected in early 2027.
The project supports Red Eléctrica’s strategy to strengthen Balearic supply security and boost capacity on the Mallorca links. Early work expanded the Mercadal and Dragonera substations for new renewables. Red Eléctrica awarded NHOA Energy the battery-supply contract in November 2024, following a €99.87 million ($114.5 million) tender.
Mercadal construction began in February 2025 with a €50 million investment: two 25 MW units totaling 37.5 MWh, fully integrated into the transmission network. San Antonio adds 90 MW/67.5 MWh, strengthening the Mallorca-Ibiza link and adding operational flexibility.
The project uses modular cabinets rather than large containers, easing installation, site-specific configuration, and maintenance; independent liquid cooling per cabinet extends performance and lifespan. Mercadal uses 176 modules for its 50 MW/37.5 MWh; San Antonio’s larger array reaches 90 MW/67.5 MWh.
A shared control system links both sites, functioning as one storage resource for the Balearic grid.
From pv magazine España
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