Special arrangements to connect Olkiluoto 3 to the main grid

Fingrid and Teollisuuden Voima (TVO) have begun preparations to connect Olkiluoto 3 to the main grid. The connection will require special arrangements because, once completed, Olkiluoto 3 will be considerably larger than earlier electricity production units.

Located in Eurajoki, Olkiluoto 3 will have a net power output of 1,600 megawatts.

The Finnish electricity system can withstand a fault in a power plant with a maximum size of 1,300 megawatts. During planning of the nuclear power plant, Fingrid and TVO reached a preliminary agreement concerning so-called system protection, which will be used to connect the plant unit to the electricity system. In technical terms, the arrangement means that if Olkiluoto 3 is disconnected from the grid, industrial consumption will be limited in nearly real time so that the disturbance in the electricity system remains within the allowed 1,300 megawatt limit.

Fingrid and TVO have now agreed on practical implementation of the system protection for Olkiluoto 3. In addition, the authorities have ensured that implementation of the system protection will not have an impact on Fingrid’s handling of system responsibility. The next step involves carrying out competitive bidding for the industrial consumption included in the system protection.

In addition to system protection, other preparations for connecting Olkiluoto 3 to the main grid include reducing electricity import capacity from Sweden by 300 megawatts via northern AC connections and increasing the volume of Fingrid’s fast disturbance reserve.

As the transmission system operator with system responsibility under the Electricity Market Act, Fingrid must ensure the technical functioning of the electricity system and maintenance of national system security. The reliability of system protection and the sufficiency of its loads are prerequisites for maintaining the security of the electricity system.

According to the supplier’s updated schedule, regular electricity production at Olkiluoto 3 will begin at the end of next year.