Kostolac Wind Farm: 145 Million Euros, Still No Power

The contractual deadline for completing the Kostolac wind farm expired on October 30, 2024. Nearly two years later, twenty wind turbines with a combined capacity of 66 megawatts still stand on the reclaimed land of closed surface coal mines, and none of that capacity is feeding Serbia’s power grid. The plant’s owner, state utility Elektroprivreda Srbije (EPS), has not said when it might start operating again.

The total value of the investment is 145 million euros. The financing breaks down as follows:

• loan from the German development bank KfW: 110 million euros
• grant funding from the European Union, through the Western Balkans Investment Framework: 31 million euros
• KfW donation: 1.8 million euros
• EPS’s own funds: 2.2 million euros

The loan agreement with the German development bank was signed in 2017, setting the October 2024 deadline. The equipment was supplied by the German Spanish company Siemens Gamesa, itself formed that same year, 2017, through the merger of Siemens’s wind energy division and Spain’s Gamesa. The turbines were erected at the Drmno, Petka, Cirikovac and Klenovnik sites, on land belonging to the Kostolac thermal power plant and mining complex. The installed capacity of 66 megawatts across twenty units works out to 3.3 megawatts per turbine.

The Trial Run Showed the Plant Works

EPS put the Kostolac wind farm into trial operation in late November 2025, and by the end of that year all twenty units were connected to the grid. As of February 22, 2026, the plant had delivered 37.37 gigawatt-hours of electricity during trial operation, with all twenty turbines running in automatic mode.

According to earlier estimates published on the EPS website, the wind farm was expected to generate around 115 million kilowatt-hours a year, enough to supply about 30,000 households. The 37.37 gigawatt-hours delivered during trial operation therefore came close to a third of the projected annual output, achieved in under three months over winter. Judging by that figure, the technical side of the job works.

Production stopped after the trial run ended. The reason given is unfulfilled contractual obligations on the part of the equipment supplier, not weather conditions or an equipment fault.

Two Statements That Do Not Match

This is where the story stops being a technical one. In June 2026, asked why the plant was not operating, EPS stated that no handover had taken place at all:

Given that a year and a half after that deadline the contractor had not fulfilled its contractual obligations, Elektroprivreda Srbije did not sign the taking over certificate, so from EPS’s standpoint as investor the project is still not finished. EPS is continuously working to overcome this situation and has shown readiness for active cooperation with the contractors in order to remove the key obstacles and successfully complete the project, which is in the interest not only of EPS but also of the contractor and equipment supplier Siemens Gamesa, as well as of all participants, including the donors and creditors, namely the European Union and the German development bank.

Less than a month later, in mid-July, EPS and Siemens Gamesa issued a joint statement with the opposite content. It says that construction and installation work was successfully completed and that the handover did take place:

With the issuance of the Taking Over Certificate by the Engineer, on March 6, 2026, it was confirmed that the wind farm was operational at that time.

The gap between the two statements is not a matter of wording. In the first, the investor claims it never took over the plant. In the second, it claims it took over the plant five months earlier. Neither statement gives a date for when the plant will restart.

Why March 6, 2026 Matters Financially

The taking over certificate is not just a formality between buyer and supplier. The European Union has stated that all 31,003,040 euros in grant funding had been drawn down by March 2026, after the engineer, under the rules of the International Federation of Consulting Engineers, issued the taking over confirmation. The same document EPS described in June as unsigned served as the basis for releasing the final tranche of European money.

The European Union added that the project is monitored through semi-annual portfolio reviews with leading international financial institutions and through annual implementation reports, alongside monthly technical assistance reports from the Western Balkans Investment Framework, and that projects it finances are subject to audit by the European Court of Auditors.

The German development bank confirmed it is following the situation:

We are aware of the temporary standstill, after the installation works on the project were successfully completed, as stated in the Politika article from July, which was confirmed by the issuance of the Taking Over Certificate.

The bank added that it is taking part in talks with all interested parties, with the goal of resolving the remaining issues so the project can deliver its expected benefits.

When Does the Kostolac Wind Farm Restart?

There is no answer. EPS, Siemens Gamesa and the Ministry of Mining and Energy did not respond to questions about the project’s status. The actual subject of the dispute has not been officially named. Unofficially, it has been said that the sticking point is the supplier’s request for additional maintenance funds, but no side has confirmed that.

The cost of the standstill can be measured. On an annual basis, that is roughly 115 million kilowatt-hours missing from the grid, in a year of record low water levels and high consumption, while the 110 million euro loan keeps running on its agreed schedule regardless of whether the blades turn. The Kostolac wind farm was meant to be EPS’s first wind power generating facility and a reference point for every state owned renewable energy project that followed. Instead, the first public record it has left behind is two statements from the same company that contradict each other.