Romania’s Cernavodă Unit 1 is scheduled to resynchronise on 6 November after more than three months offline, making the reactor’s return a key factor for Southeast Europe’s winter power supply. The return of existing nuclear capacity is central to the regional outlook as governments assess nuclear generation’s longer-term role alongside expanding wind and solar.
The outage followed low Danube water levels, while Unit 2 remains dependent on a sustained hydrological recovery. Each reactor has a capacity of around 700 MW; the return of one or both would change Romania’s import requirement and the power balance in Hungary, Bulgaria and Serbia.
Romania is also preparing a long-term refurbishment of Unit 1 to extend its operating life for another cycle. The European Investment Bank (EIB) approved an 800 million euros financing envelope for the programme, which has an estimated total cost of 3.2 billion euros. Investment in maintaining existing nuclear capacity can run to billions of euros before new-build projects are considered.
Bulgaria’s nuclear generation is anchored by the 2 GW Kozloduy plant. Unit 6 entered annual maintenance on 8 October and is scheduled to return at the end of November.
Hungary’s four Paks reactors supply around half of domestic generation, and Unit 4 completed its 2026 maintenance at the start of November. Construction of Paks II started in 2026, reinforcing the country’s long-term commitment to nuclear power.
Krško is a key firm power asset for Slovenia and Croatia. It supplied 487 GWh net in September with 100% availability and has an approved lifetime extension.
Greece has no nuclear power plant, but established a government committee in 2026 to examine whether to pursue a national nuclear programme. No decision to build a plant has been taken; the country increasingly relies on gas to cover hours when non-renewable generation is unavailable.
Reactor availability will affect winter prices before new nuclear projects can influence supply. Delayed restarts or additional outages during cold periods with low wind would increase import needs and put renewed pressure on neighbouring markets.
