Slovenia’s Šoštanj thermal power plant expects to bring Unit 6 back to service before the winter heating season following inspections that uncovered damage in the turbine’s intermediate-pressure section. The restart is targeted for October, according to the plant’s schedule for returning the unit ahead of seasonal demand.
Damage found during planned summer overhaul
Elevated vibration was detected shortly before the unit entered its planned summer overhaul. Engineers working with specialists from GE Steam Power identified damage in the turbine’s labyrinth section, leading to a wider technical inspection.
The inspection results pointed to an issue affecting the turbine’s intermediate-pressure section. Further checks were expanded beyond the initial findings as part of the technical review.
Refurbishment in Berlin and further high-pressure checks
The affected component cannot be repaired in Slovenia and was transported to GE’s facility in Berlin for refurbishment. The turbine’s high-pressure section is also undergoing a full inspection as a precaution against additional defects.
Commissioning tests are scheduled to begin in mid-October 2026, provided the repair is completed and inspections deliver satisfactory results. The timing is intended to allow Unit 6 to return before electricity and district-heating demand increases during winter.
Regional generation constraints and settlement arrangements
The outage has implications beyond Šoštanj itself. Slovenia is already exposed to lower nuclear production at Krško and hydrological constraints linked to drought and high river temperatures.
A delayed return of Šoštanj would increase reliance on imports during a period when neighbouring systems may face similar generation restrictions. The repair work is being carried out under a settlement agreement previously concluded between the plant and GE.
The settlement includes a long-term service contract worth approximately €110mn, covering planned maintenance, spare parts, manufacturer support and digital upgrades through 2029–2030. The final cost of the current intervention has not been determined, with allocation depending on detailed terms covering warranties, defect responsibility and classification of the damaged component.
Mid-October commissioning window leaves limited contingency
The October target leaves limited schedule contingency for commissioning preparations. Any further defect discovered in Berlin or during reassembly could delay commissioning into the heating season.
The heating season timing is described as materially higher value for the unit, based on system conditions expected during winter demand periods.
