Only four of around 50 Danish data centers are using their surplus heat, according to a new tally from the Danish Energy Agency. Most of the heat is still released into the air.
DR reported on August 15, 2026 that the Energy Agency counts four out of 50 data centers making use of excess heat. When many of the facilities were established in Denmark about ten years ago, surplus heat was highlighted as one of the positive effects.
At the time, it was said that the heat could contribute to local heat supply. According to DR, that has not happened at the majority of the sites. The heat is vented into the air instead of being used for household heating.
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Data center servers run around the clock, and the facilities cannot use the large amounts of heat they generate themselves. Henrik Hansen, director of the industry association Datacenterindustrien, puts the number of centers using surplus heat at seven, not four. He told Ritzau that it has proven more difficult than most imagined, as reported by DR.
Tax and price cap cited as obstacles
Hansen says legislation has made it hard for the companies. Surplus heat has been subject to a tax and a price cap, which he describes as a poor business model. Following a law change in 2022, companies can avoid the tax if they enter an arrangement with the Energy Agency.
Climate, energy and supply minister Samira Nawa says surplus heat from data centers should in principle be used, but that it has to make sense locally. In a written answer to Ritzau, cited by DR, she said the assessment depends on the site’s position relative to the district heating grid and on whether pipes and equipment must be installed. She added that it must not result in larger heating bills for residents of municipalities that host data centers.
TV MIDTVEST reported the same Energy Agency figure and noted that even fewer centers channel heat into district heating networks. In most cases, the outlet reported, the heat is simply released into the air rather than used for homes or industrial processes. BT also reported the four out of 50 figure and the gap between expected and actual use.
Hansen expects use of surplus heat to rise because of new EU guidelines. According to him, there is now a different incentive and pressure to examine all available options, DR reported.
Guidance from the Danish Energy Agency states that rules implementing EU requirements took effect on October 11, 2025. The rules require certain companies, including data centers above 1 MW, to submit cost-benefit analyses. The analyses are intended to assess whether surplus heat can be used profitably, including in district heating.
