Serbia’s 66 MW Kostolac wind farm remains offline while EPS and turbine supplier Siemens Gamesa continue to work through outstanding issues affecting formal handover and commercial operation. The project is an EUR 145 million development with all 20 turbines installed and connected to the grid. Electricity generation has taken place during trial operations, but regular commercial output has not started.
Commercial operation has not begun nearly two years after the project’s original completion target of October 2024. EPS said in June that Siemens Gamesa had not met all contractual obligations, which led the utility to decline signing the Taking-Over Certificate. A joint statement released the next month said the project engineer issued the certificate on 6 March 2026, confirming completion of construction and installation works.
Trial generation and continued suspension
Trial operation at Kostolac started in November 2025, with all 20 turbines connected to the grid by the end of that year. The wind farm delivered 37.37 GWh of electricity to the grid by 22 February 2026. Generation was then suspended, and no timetable has been announced for restarting operations.
The companies involved stated they would continue working together to address remaining matters after the certificate issuance. The specific grounds for keeping the plant shut have not been clarified publicly. Unconfirmed reports have linked the dispute to additional maintenance payments, but EPS, Siemens Gamesa and Serbia’s Energy Ministry have not disclosed detailed information on the outstanding contractual points.
Expected output and financing structure
If fully operational, Kostolac is expected to produce about 115 GWh annually. That level of generation is described as sufficient to cover consumption equivalent to around 30,000 households. The project’s completion is also cited as part of Serbia’s efforts to expand renewable generation and reduce reliance on a power system still heavily dependent on coal.
The project received primarily international development support. KfW provided EUR 110 million in loans and a EUR 1.8 million grant, while the European Union contributed EUR 31 million through the Western Balkans Investment Framework. EPS added an additional EUR 2.2 million.
The EU said its contribution had been fully disbursed by March after issuance of the certificate by the FIDIC project engineer . The funding structure reflects the role of Kostolac as one of Serbia’s major publicly supported renewable-energy projects . Despite technical readiness indicated by installed and grid-connected turbines, unresolved contractual and operational matters continue to prevent entry into regular service.
