Slovenia and Italy Ink €250 Million Deal for Major Cross-Border Grid Upgrade

Historic Agreement Signed

Slovenian and Italian electricity transmission system operators, ELES and Terna, have officially signed an agreement for a substantial cross-border grid upgrade. The joint investment, valued at approximately €250 million, is set to significantly enhance electricity transmission capacity between the two nations. The agreement, finalized on November 10 or 11, 2025, marks a crucial step towards deeper market integration and improved energy security in the region.

Boosting Transmission Capacity

The ambitious project is designed to increase cross-border transmission capacity by an additional 600 megawatts (MW), representing a more than 50 percent increase in physical transmission capacity between Slovenia and Italy. This expansion is vital for managing growing electricity imports and exports, particularly as countries transition away from fossil fuel-based energy production.

The upgrade encompasses three key improvements:

• The 400 kV Divača–Sredipolje (Redipuglia) line will see its phase-shifting transformer at the Divača substation upgraded with a new third unit, raising its capacity from 1,200 MVA to 1,800 MVA.
• The 220 kV Divača–Padriče (Padriciano) line will undergo an upgrade of its phase-shifting transformer at the Padriče substation and its conductor, utilizing low-sag or low-voltage conductor technology. This will double its capacity from 350 MVA to 700 MVA.
• On the Italian side, the 220 kV Padriče–Sredipolje (Redipuglia) link and the Sredipolje substation will be upgraded with a new transverse or phase-shifting transformer to optimize internal power flow management.

Project Timeline and Funding

Construction work for the grid upgrade is projected to commence in 2029, with the entire project slated for completion by the end of 2031. The total investment of approximately €250 million will be shared, with Slovenia's portion estimated at €90 million and Italy's at €160 million. ELES has indicated its intention to apply for European funds to finance the investments on the Slovenian side.

Strategic Importance for Regional Energy

This collaboration is seen as a strategic investment for the future, ensuring the reliability, resilience, and connectivity of the electricity grid. Aleksander Mervar, CEO of ELES, emphasized that 'With an additional 600 MW of cross-border capacity, Slovenia is solidifying its role as a key electricity hub between Central and Southern Europe and as a reliable regional partner.' Enrico Maria Carlini, Head of Power System Planning and Permitting at Terna, added that the agreement 'reinforce our long-standing high-level cooperation.' The upgrade is expected to significantly strengthen market integration and the adequacy of the interconnected power system.