Šoštanj Unit 6 in Slovenia shuts early after technical fault, with heat supplied via gas turbines

Operations at Slovenia’s Šoštanj Thermal Power Plant were interrupted earlier than planned after Unit 6 went offline on 10 April, just one day before its scheduled seasonal shutdown. Plant data showed a sharp decline in output during the morning hours, consistent with an unplanned technical stoppage rather than routine operations.

Fault prompts safety shutdown ahead of seasonal maintenance

The operator said Unit 6 had already been set to shut down on 11 April after the evening peak in electricity demand, when heating needs from nearby Velenje were expected to fall. That timeline was brought forward when a technical fault triggered the plant’s safety response system.

In its account of the incident, the plant reported that a disturbance in the generator caused increased turbine vibrations. Those conditions led to an automatic shutdown of the turbo-generator unit. After the event, Unit 6 was taken out of operation.

Heat supply maintained using gas turbines

Although power generation from Unit 6 stopped earlier than expected, heat production was maintained using gas turbines to ensure continued supply. The operator indicated that this approach helped bridge the gap until thermal demand patterns and maintenance timing align again.

Return expected around mid-September

Despite the unexpected nature of the interruption, the outage remains closely aligned with the originally planned maintenance schedule. The operator expects Unit 6 to return to service around mid-September, when seasonal demand for thermal energy typically rises as colder weather approaches.