European energy security
Europe's firm capacity turns out to be weather-dependent: river-cooled nuclear and hydropower fail in exactly the weeks a heatwave pushes demand to its peak. Hungary and Romania held the grid together with imports and with large users asked to switch off, and the wind Denmark is buying instead arrives in 2032.

A nuclear reactor is a machine for boiling water, and it needs a much larger flow of cold water to carry the waste heat away. Hungary's Paks plant draws that cooling water straight from the Danube, and Romania's Cernavodă takes it from a Danube branch. When the river drops far enough the intakes no longer reach it, and the reactor has to come down whatever the state of its fuel or its grid. The same drought cuts what the hydropower plants can generate.
That is what happened in the last week of July 2026. Romania's National Institute of Hydrology put the flow where the Danube enters the country at about 1,600 cubic metres a second, less than a third of the July average of 4,700. Paks, which supplies about half of Hungary's electricity, went fully offline for the first time since it opened, taking 2,000 megawatts out of the system. Romania shut one of Cernavodă's two 706 megawatt reactors and declared a national energy alert for August.
Demand moved the other way in the same week, because the heat that emptied the rivers also switched on the air conditioning. A grid short of supply then has two immediate answers, imports and demand. Hungary asked households to shift consumption out of the 17:00 to 22:00 peak and began preparing rules to disconnect large users in rotation. In Romania more than eighty energy-intensive companies were to cut back from 4 August, and the Dacia and Ford car plants stopped until 19 August.
Neither answer is free. Imports only help if a neighbour has spare power, and a continental heatwave is when neighbours have least to spare. Romania went as far as asking Ukraine for emergency evening supply from one of Ukraine's nuclear plants. Price carries the remainder: Eurostat's flash estimate put euro area energy inflation at 10.0 percent in July 2026, against 8.5 percent in June. The contested question is therefore what to build so that a dry August stops costing this much.
One answer is offshore wind. Denmark tendered at least 1.8 gigawatts across two sea areas. On 4 August 2026 a trade outlet reported that Vattenfall had won, but the contracts were unsigned and the Danish Energy Agency's own page still called the evaluation open. Denmark went back to subsidy after its unsubsidised North Sea round drew no bids in December 2024. Otto Brøns-Petersen of CEPOS attacked the subsidy plan in May 2025, arguing the state should tender only as fast as private investors will fund.
”This means that from Monday at the latest 2,000 megawatts will drop out of Hungarian energy production, while residential and public electricity demand keeps rising because of the intensifying heat.”
The numbers
What the comparison shows
Where they agree
Nobody disputes the mechanism. Low water stops the cooling flow, a river-cooled reactor comes down, hydropower falls with it, and the shortfall lands in the evening peak that the same heat has made larger. Hungary and Romania reached for the same two short-term tools: imports from neighbours, and asking large users and households to consume less in the evening. The Commission offered coordination rather than power, saying it stands ready to convene its Electricity Coordination Group. The response was demand-side and short-dated, measured in weeks.
Where they split
The argument is about what to build. Denmark's answer is to guarantee a price for twenty years so that offshore wind gets built at all, after an unsubsidised tender drew nothing. Otto Brøns-Petersen of CEPOS argued in May 2025, against the plan rather than against the result, that the state should only tender at the pace private money will fund, and that guaranteed prices hide the size of the bill. Ciprian Cherciu puts storage and a broader mix ahead of any single new plant. On scale, Hungary's government describes a crisis within days, while Energiaklub's András Perger expects the region to absorb the loss.
What nobody is saying
Nobody names the planning number. None of these sources says how much a river-cooled reactor should be counted on in a dry August, and none cites a European rule that sets one. Interconnection assumes neighbours run short at different times, which Bolojan says is not the case this summer: demand for imported power is just as high next door. The timelines do not meet either. The Danish farms are meant to run from 2032, if the contracts are signed, while the shortfall arrives every summer in between.
Who says what
Says an energy crisis could start within days. He says the shutdown and the cost of the emergency imports could have been avoided if the Orbán government had built the new pumping station at Paks. Asks households and large users to move consumption out of the 17:00 to 22:00 peak, and says the government has begun preparing legislation to disconnect big consumers on a rotating basis if reserves, imports and voluntary restraint are not enough.
”Ez azt jelenti, hogy legkésőbb hétfőtől 2000 megawatt kiesik a magyar energiatermelésből, miközben a fokozódó hőség miatt folyamatosan nő a lakossági és közületi villamosenergia-felhasználási igény.”This means that from Monday at the latest 2,000 megawatts will drop out of Hungarian energy production, while residential and public electricity demand keeps rising because of the intensifying heat.
The institutional position. Brussels says it is watching Hungary and Romania and stands ready to convene an ad hoc meeting of the Electricity Coordination Group, which the Commission says would help share information and coordinate next steps in the region. She stressed at the same time that there are currently no immediate energy security concerns.
”Although the operator has emergency measures in place to guarantee nuclear safety, an event of this kind could further strain the regional electricity balance”Although the operator has emergency measures in place to guarantee nuclear safety, an event of this kind could further strain the regional electricity balance
Declared a nationwide energy alert for August and put the arithmetic in public: the evening deficit is being covered by imports, and losing the second Cernavodă reactor would mean losing about 20 percent of national generation. Has asked Ukraine for emergency evening supply from one of Ukraine's nuclear plants, and pressed large industry to cut or reschedule.
”Față de un consum normal de peste 7.000 MW în orele de seară, importăm aproximativ 1.700 MW. Dacă se oprește și grupul doi, ar trebui să importăm peste 2.500 MW.”Against a normal consumption of over 7,000 MW in the evening hours, we are importing around 1,700 MW. If the second unit stops as well, we would have to import over 2,500 MW.
Cuts against the alarm. He puts Hungary's loss at 25 to 30 percent of output and calls it a serious test of national and regional supply, but does not expect the shutdown to create serious problems for the region. He notes that imports can cover part of the gap, while adding that hydropower availability is itself limited across the region.
”Although the situation in Hungary is stretched, I don't expect this to cause serious regional problems”Although the situation in Hungary is stretched, I don't expect this to cause serious regional problems
Says Romania lacks a coherent national energy strategy. He would have refurbished the hydropower plants, built new generating capacity and expanded wind and solar as an alternative for the weeks the nuclear plant cannot run at full output, and puts electricity storage above all of it.
”Above all, Romania should have invested in developing electricity storage capacity. This is an area where the country remains significantly underdeveloped”Above all, Romania should have invested in developing electricity storage capacity. This is an area where the country remains significantly underdeveloped
The dissent on the supply side, written fifteen months before the award. In May 2025 he attacked a support plan the government was then negotiating, arguing that offshore wind should be tendered at the pace private investors will fund, and that guaranteed prices leave neither politicians nor voters able to see what the final bill is. He put that plan at up to 50 billion kroner before VAT for three gigawatts.
”Hvis havvind skal være støttefri, skal man skal belave sig på at udbygge i den takt og det omfang, der er markedsmæssig interesse for, og ikke beslutte udbygningstakten blandt folketingspolitikere omkring et forhandlingsbord.”If offshore wind is to be subsidy-free, you have to be prepared to build out at the pace and on the scale there is market interest for, and not decide the pace of build-out among members of parliament around a negotiating table.
Our coverage
- Drought forces Poland to cut coal output as the Vistula runs lowFriday, 7 August 2026
- Romania on energy alert: Dacia and Ford halt production as drought cripples power supplyWednesday, 5 August 2026
- Vattenfall wins both Danish offshore wind tenders after Denmark restored subsidiesTuesday, 4 August 2026
- Hungary's only nuclear plant close to shutdown as the Danube falls to record lowsMonday, 3 August 2026
- Hungary shuts down its only nuclear plant as the Danube hits record lowsSunday, 2 August 2026
- Euro area inflation rises to 2.9 percent in July as energy prices climb 10 percentFriday, 31 July 2026
- Record-low Danube shuts down Paks, and the Commission weighs an emergency meeting on power supplyFriday, 31 July 2026
- Record low Danube forces Hungary's only nuclear plant to shut downThursday, 30 July 2026