EuroOilWatch Analysis — the drought crosses from freight and power prices into baseload generation.
What happened
Romania's Nuclearelectrica began a controlled disconnection of Unit 2 at the Cernavodă nuclear plant on Thursday 13 August, after water levels in the Danube fell below the threshold the plant's cooling-water intake requires. Levels at the plant were reported at 182cm on 12 August against the 185cm needed to operate.
Unit 1 has been offline since late July for the same reason.
With both units down, Romania's only nuclear station is entirely out of service. Cernavodă normally supplies roughly a fifth of the country's electricity.
What replaces it
Romania's response is a substitution across three sources.
The 330 MW Rovinari 4 lignite unit is being brought out of reserve at Complexul Energetic Oltenia. Hidroelectrica is supplying additional capacity — though within the limits of the same drought-constrained water resources that closed the nuclear plant. The balance is expected to come from regional imports.
That is a workable short-term arrangement. It is also a more expensive, more carbon-intensive and less firm one than the plant it replaces, and two of its three legs depend on conditions outside Romania's control: the weather, and the willingness of neighbouring systems to export during a region-wide heat event.
Why this is different from what came before
Low water has been shaping European energy all summer, but mostly at the margins of the system: barge loadings restricted on the Rhine, freight costs rising, thermal plants trimming output as cooling water warmed. France has trimmed nuclear output on low, warm rivers. Hungary's Paks plant came within a turbine of the first complete shutdown in its 44-year history before a temporary rise in the Danube kept one machine online.
Those were constraints. This is a removal.
A country's entire nuclear baseload has been taken off the grid — not by fault, sanction, attack or fuel supply, but because the river that cools it is too low. The distinction matters because baseload is what the rest of the system is planned around. Everything else — the lignite restart, the hydro top-up, the import capacity — is now doing a job that a single plant used to do on its own.
What it says about the buffer
Romania tried to engineer its way out first. Its military detonated a rock formation in the Danube earlier this month to redirect water toward the plant; the defence minister said the level at Cernavodă rose 2cm rather than falling 2cm.
That intervention bought time. It did not hold.
This is the pattern that has run through the summer: each buffer absorbs the shock until it cannot, and the absorption is invisible right up to the point of failure. Storage covers a supply gap until the storage is gone. A river carries freight at reduced draught until the draught runs out. A nuclear plant runs on one reactor, then on emergency water-routing works, and then not at all.
The relevant question for the rest of Europe is not whether Romania can cover this month. It probably can. It is what remains available if the next shock arrives before the river recovers — and river levels are now an energy-security variable, not simply a transport or agricultural one.
Verified from Romanian and regional reporting of Nuclearelectrica's and the Energy Ministry's statements. Danube levels at Cernavodă and the operating threshold are as reported on 12 August. EuroOilWatch has not independently measured river levels or plant conditions.