Denmark imports record power as grid hits limits

A grey, still day over the North Sea. No wind, no sun. The Danes call it a dunkelflaute: a stretch when wind and solar output collapse together across a wide area. For Denmark, which has retired much of its domestic backup generation, these dead calms force the grid to pull power through undersea cables from Sweden, Norway and Germany (Politiken). Denmark imported more electricity from neighbours in 2025 than in any previous year (Portfolio.hu). That growing dependence tests a bet spreading across Europe: that cross-border cables can replace the power plants countries are shutting down.

Denmark's grid is running out of room

Weather is only the first problem. Energinet, the Danish grid operator, says data centres, hydrogen plants and battery projects have applied for connections totalling about 60 GW, roughly eight times the country's current peak demand (Energinet). Much of that is speculative: companies file early, and many projects will never get built. But even a fraction would strain a grid that already cannot keep up. Energinet has stopped accepting new transmission-level connection requests.

District heating shows the squeeze from the demand side. About one in four Danish district-heating companies report delayed grid connections or less capacity than they requested. The industry group Dansk Fjernvarme projects that district heating's electricity share will jump from roughly 10% today to 45% by 2035 (Via Ritzau). More electric demand, fewer domestic plants, the same constrained grid.

Who sells power, who pays for it

Europe's electricity market moves power from cheaper areas to more expensive ones through cross-border cables until those cables fill up (European Commission). That works when shortages are local. It fails when everyone is short at once.

France shows what happens when you keep power you can switch on. In the first half of 2026, France exported a net 51 TWh, earning producers about €3 billion and generating roughly €1.3 billion in cable-usage revenue for RTE, the French grid operator (Le Figaro). France sold at an average of about €61.9/MWh. Importing countries paid nearly double, around €111.6/MWh (Les Énergies Renouvelables). Nuclear power lets France produce on demand and earn when neighbours are short.

Even so, French household tariffs will rise 2.5% on 1 August for about 19.37 million households (Challenges). Grids and backup capacity cost money regardless of the wholesale price. In the same six months, French wholesale markets logged 407 hours of negative prices, moments when surplus electricity had nowhere profitable to go, yet the infrastructure bill keeps climbing.

Sweden reveals a different split. Its grid is divided into pricing zones, so southern regions nearest Denmark face higher wholesale costs when Danish demand pulls power across the border (GP). Swedish generators profit from selling into a tight Danish market. Swedish households in the same zones pay more. The Danish island of Bornholm gets only 35 MW of guaranteed import from Sweden, well below the cable's technical limit, because stress on southern Swedish grids caps what can be promised (Bornholm.nu).

Germany is buying its own insurance. The Bundesnetzagentur, Germany's energy regulator, holds 7,407 MW of grid reserve for winter 2026/27: plants kept outside the normal market and switched on only in emergencies (Bundesnetzagentur). Berlin passed a capacity-market law in May 2026 that will pay plants and batteries to exist and stay ready, even when they rarely run. That is backup Denmark chose not to keep.

Finland underlines the physical risk. When one of its two undersea links to Estonia went offline for repairs, prices spiked and supply tightened immediately (Grivolt). A cable can be cut, congested, or down for maintenance at the worst moment.

ENTSO-E, the body coordinating Europe's grid operators, runs continent-wide checks on whether countries will have enough power during stress periods, because cross-border help is conditional, not automatic (ENTSO-E, ACER). Denmark lays bare the deal underneath Europe's green grid: cables lower costs in normal times, but they do not guarantee power when wind dies across an entire region. Countries that kept plants they can switch on will set the price. Countries that trusted the cables may pay more in the hardest hours.