EMS signs contract to upgrade Bajina Bašta substation to 400 kV

Serbia’s grid modernisation push is moving from planning into construction, with Elektromreža Srbije (EMS) signing a contract to expand and reconstruct the Bajina Bašta substation into a higher-voltage hub. The upgrade—moving from 220/35 kV to 400/220/35 kV—matters for investors because it shifts part of western Serbia’s transmission backbone onto a more capacity-rich platform at a time when the system must handle growing renewable output and cross-border power flows.

Contract scope: Bajina Bašta expansion and Obrenovac line-bay works

The works awarded after an international tender will be carried out by a consortium of Energotehnika Južna Bačka and Elnos. In addition to the Bajina Bašta substation reconstruction, the project includes fitting out two 400 kV line bays at the Obrenovac substation. EMS designed this step to connect with a new double-circuit 400 kV transmission line currently being built between the two sites.

Part of the third phase of Serbia’s grid-modernisation programme

Financially, the investment forms part of the third section of Serbia’s grid-modernisation programme that links Bajina Bašta and Obrenovac with a new 109-kilometre 400 kV line. That section is valued at €113.5 million, with completion targeted for the end of 2028.

Funding will come from a €64.5 million KfW loan, a €21 million grant from the Western Balkans Investment Framework, and EMS’s own resources—mixing external development finance with internal capital allocation.

Why the voltage shift is strategically important

The core significance is not only the civil and electrical scope but the voltage upgrade itself. EMS is effectively replacing part of an aging 220 kV backbone in western Serbia with a more modern 400 kV platform. The expected benefits include higher transmission capacity, improved system reliability, and network readiness for a heavier mix of generation alongside increased cross-border flows.

That preparation becomes more relevant as Serbia deepens regional market coupling and faces mounting pressure to integrate additional renewable capacity without compromising grid stability.

Support for flexibility needs, including pumped storage

EMS also positioned the upgrade as part of future system flexibility. The company said it will help create technical conditions needed for integrating new production assets, including the planned Bistrica pumped-storage hydropower plant—widely viewed as one of Serbia’s most important balancing resources in its medium-term power strategy.

In that sense, EMS’s work goes beyond routine network refurbishment: it becomes part of an infrastructure base intended to strengthen dispatch flexibility, reserve support, and westward transmission capability.

Broader implications for Serbia within the Trans-Balkan Corridor

The contract also underscores how the Trans-Balkan Corridor—valued at around €221 million—is reshaping Serbia’s position in south-east Europe’s electricity network. Earlier corridor sections connected Pančevo 2 to the Romanian border and Kragujevac to Kraljevo, while later stages are expected to extend from Bajina Bašta toward Višegrad and Pljevlja. Those extensions are intended to increase cross-border transfer capacity toward Bosnia and Herzegovina and Montenegro.

Taken together, EMS’s decision reflects a broader logic: rather than reinforcing one node in isolation, Serbia is steadily positioning itself as a higher-capacity regional transmission hub between eastern and western power markets.