There has been overheating in an engine at Ringhals 2, causing smoke, but there are no visible flames, Anna Wallrud, press manager at Ringhals, tells TT.
The fire service has been on site and the alarm has been cancelled. No injuries have been reported.
According to Wallrud, there are no operations in the area where the smoke was generated.
There is a construction site at Ringhals 2. It is being dismantled.