Slovakia prepares major power boost as Mochovce 4 approaches grid connection

Slovakia is preparing to add another major source of electricity to its transmission network as the fourth reactor at the Mochovce nuclear plant moves towards grid connection. Transmission system operator SEPS expects the unit to begin supplying the national network in the first half of October, following several months of technical preparations.

The 471 MW reactor is currently progressing through its commissioning programme after receiving regulatory approval in September to move into the power start-up phase. Output is being increased gradually while operators test the reactor and associated systems under different conditions. Connection to the transmission network is expected when the unit reaches approximately 20% of its rated capacity.

Preparations have extended beyond the power station itself. SEPS has adapted operating systems, documentation and infrastructure associated with the 400 kV Veľký Ďur substation, which will receive electricity generated at Mochovce. Modernisation of the surrounding transmission infrastructure is continuing as Slovakia prepares the network for the additional generating capacity.

Once commissioning is completed, Mochovce 4 is expected to provide electricity equivalent to around 13% of Slovakia’s annual consumption. The unit will still have to pass further tests at increasing output levels before completing the process required for regular operation.

The timing is significant for Slovakia’s industrial economy. Manufacturers, battery producers, technology companies and other electricity-intensive businesses are placing greater emphasis on power availability and network reliability when assessing investment locations. Additional national generation does not automatically provide connection capacity at individual industrial sites, but it strengthens the wider electricity system on which future development depends.

Mochovce 4 therefore represents more than an expansion of Slovakia’s nuclear fleet. Combined with investment in transmission infrastructure and energy storage, the additional capacity strengthens the country’s underlying energy platform at a time when access to dependable electricity is becoming an increasingly important factor alongside labour, transport links and available industrial land in competition for new investment.