Cernavodă shutdown strains five power grids

At 19:25 on Tuesday, Romania was consuming more than 8,000 MW of electricity. Its plants were producing 5,873 MW. Imports filled the 2,150 MW gap (Agerpres, Adevărul). That gap is about to widen. Romania began preparing to shut down Cernavodă Unit 2, its only running nuclear reactor at roughly 700 MW, because Danube water levels can no longer cool it safely (Argus, Economica). The immediate test is whether five countries can share scarce evening power without someone paying a steep price.

Why 19:00 matters

The problem is timing. During the day, solar panels flood the grid with cheap power. But between 19:00 and 23:00, air conditioning still runs while solar output drops to zero. Romania, Hungary, Bulgaria and their neighbours all need firm generation or imports at the same hour.

Romania formally notified Brussels and neighbouring countries that it had entered an electricity crisis. The legal basis is EU Regulation 2019/941, which requires governments to alert the Commission and their neighbours when supply is at risk (HotNews, Ziare). The Commission convened an Electricity Coordination Group on 11 August and concluded the system was strained but stable (European Commission, Digi24). That lowers blackout risk. It does not lower evening prices.

Europe's single market can route electricity from cheaper zones toward stressed ones through market coupling (the automatic process that shifts power across borders until cables are full). It cannot create new megawatts.

Who sells, who buys

For now, Bulgaria has the better side of the trade. Romanian and Hungarian traders requested 3,500–4,000 MW of Bulgarian cross-border capacity, according to ESO dispatch director Dimitar Zarchev (Mediapool). But Bulgaria's Kozloduy nuclear plant sits on the same river, and energy minister Iva Petrova said it could keep running about another week and a half at current Danube levels (DBR). Day-ahead prices climbed toward 150–170 €/MWh from 100–120 €/MWh a week earlier, a windfall with a visible expiry date (Mediapool).

Hungary is the most exposed buyer. Paks, its main nuclear plant, ran at half power for 11 days before returning to full output. That pushed Hungary into evening imports averaging 218 €/MWh on 4 August. One hour hit 439 €/MWh for 3,522 MW of imported power (VG, Portfolio). Slovakia's energy regulator ÚRSO warned of an "unusually tense" electricity situation across the region (STVR).

Inside Romania, households are shielded for now. The government's emergency plan targets large industrial users for staged curtailment between 19:00 and 23:00 as a last resort (Agerpres). But if suppliers keep paying more to secure power at peak hours, those costs will reach household contracts. Expert scenarios put possible day-ahead averages between 850 and 1,800 lei/MWh, with isolated evening peaks above 5,000 lei/MWh (Economica, Adevărul).

Coal, recovery money and the real trade-off

Bucharest paired the crisis notification with a familiar ask: keep coal units Rovinari 4 and Turceni 5 running beyond their planned closure dates (HotNews). Coal plants help at evening peaks because they generate regardless of sun or wind. But Romania promised to close them under its national recovery and resilience plan (the reform commitments tied to receiving EU recovery funds), and the Commission can suspend payments if those milestones are reversed (Ziare). The Commission's own conclusion that there is no short-term supply risk weakens Romania's emergency case.

Europe's grid can keep the lights on. But stability is being preserved through higher import bills, industrial curtailment plans and reserve coal politics, not through abundant supply.