This works because Denmark already has district heating pipes under most of its cities. The data center just plugged in. The real engineering happened decades ago.
As data centers consume ever more power, one facility in Denmark shows how to turn a costly cooling problem into a heating solution for thousands of households.
Almost all the electricity a data center pulls off the grid comes back out as heat. One overview of the field puts the figure at roughly 90%. A data center is, in effect, a very expensive radiator. But most of that warmth goes nowhere useful. It gets blown into the sky.
The interesting question is what a facility could do with the heat if it decided not to throw it away. Meta’s site in Odense, Denmark is one of the few places we can point to for an answer.
Where the wasted heat goes
Cooling is where the energy disappears. The Environmental and Energy Study Institute estimates that about 40% of the energy a data center uses goes to keeping the servers cool, and nearly all of that ends up as heat.
The catch is temperature. Server exhaust comes off warm but not hot, and warm-but-not-hot isn’t much good to anyone who wants to heat a building. The low temperature of that waste heat limits its direct use, so it has to be raised before it can heat homes. Which is where Odense gets clever.