Danish engineers are drawing up plans to connect an Apple datacentre to a district heating network in Denmark that will use its waste energy to heat homes and provide hot water.
This comes a decade after the US phone giant announced plans to build one capable of community integration, and five years after it started operating.
The breakthrough arrived after the Danish parliament agreed, in January, to scrap a price cap on waste industrial heat that deterred district heating operators from plugging datacentres into their networks.
With a final parliamentary bill wanting, but a government pledge it will be enforced by 1 July still standing, community firms are exhuming plans for major industrial heat reuse projects.
But while datacentres have been a focus for political campaigners and industry lobbies, demanding the immense waste heat the computer facilities emit be put to good use, the possibility of doing so looks severely limited. The breakthrough’s greater benefit may be in the public image of datacentre operators, say Danish industry experts.
Morten Abildgaard, CEO of Viborg Varme, the district heating company working with Apple on its Danish datacentre, told Computer Weekly it plans to invest in a €50m heat pipe and equipment needed to feed heat from the industrial park housing Apple’s datacentre, 4.5km out of Viborg, to residents in the city. This is 10 years after the US firm first offered it.
“Now they have decided to remove the price ceiling,” he said. “We are back on track. With the surplus heat [Apple] say we can expect to get, we have a feasible business case. We are not able to find a better heat source in winter time.
“Right now, I’m working with our engineers, finalising the technical details. I believe we can start construction on 1 October. It’s the most feasible option,” added Abildgaard, in comparison with the wood incinerators, air and water heat pumps, and even solar energy, the heat network already uses.
Even natural gas, with Denmark planning a tax to phase out fossil fuels and future price increases expected, was not as feasible as datacentre heat.
Yet little of Apple’s heat might end up being used, with the rest being exhausted “for the sparrows” on the roof, as the Danish Ministry of Climate and Energy put it when declaring in January that its political breakthrough might allow all datacentre exhaust to heat homes.
Danish heat networks have sources of much greater utility than lukewarm datacentre exhaust, according to experts. And Danish law requires heat networks to use the cheapest sources they can get.
The Apple datacentre is operating at a capacity of only about 7MW, according to Apple’s 2025 Environmental progress report. But Viborg expects it eventually to produce an over-abundance.
“If you look at the full scale of the datacentre, when it’s fully built, it will produce far more heat than we could ever use,” said Abildgaard, even with the network’s peak winter demand averaging 70MW.
Yet still Apple won’t heat the whole city, as Viborg wants multiple sources so its residents need never depend solely on one.
“If we are in that lucky situation and we have a lot of surplus heat sources, we would like to choose the best ones, and that means the hottest ones,” he said.
Contract negotiations
District heating firm DIN Forsyning has little expectation of using datacentre heat despite being in contract negotiations with several datacentre operators for whom its City of Varde is a choice location. The city has international fibre internet connections and a high-power electricity grid fed with green electricity from the North Sea, said DIN Forsyning business development manager Claus Nielsen.
DIN is meanwhile counting on two hydrogen electrolysers, adding to one already in its catchment. District heating firms moreover tended to already have invested in other sources. “That’s the reason why we’re a little bit resistant to datacentres,” he said. “Because maybe we’ll get better-grade energy from hydrogen production.
“We also have some food production where we can do heat extraction at higher temperatures, so we’re a little bit on hold in terms of how to manage [datacentres],” said Nielsen. “If you already have technologies that are sustainable and efficient then the economic value of using [datacentre] heat is quite low.”
The electrolysers alone would supply more heat than the district could use. DIN was therefore exploring ways to use it for other things such as greenhouses.
The heat firm is, however, investing in heat infrastructure to connect a planned 30MW datacentre. But that will feed only 1,700 homes initially, and perhaps 5,000 when fully operational, said press statements. That would turn about 23-70% of energy consumed by the datacentre into heat to serve about 4-10% of homes on the network, assuming it operated at half capacity when fully built.
Another datacentre being built in DIN’s catchment will feed most of its heat to a greenhouse.
Officials and heat experts were unanimous in their praise for the government removing the cap. Heat, energy and data industries alike celebrated it as a means to cut fossil fuels.
Gaining kudos
Henrik Hansen, director of the Danish Data Center Industry association, said datacentre operators got no benefit from it themselves bar the kudos, but that was not an insignificant gain.
“As a datacentre operator, you like to have these projects going, but it’s not business-critical,” he said. “It’s a way of engaging with the local community, producing this heat, and hopefully replacing some fossil energy sources used to heat up the houses.
“It’s a good narrative and a good enabler for bringing down your footprint and your climate impact, which is very important [for] datacentres today – to have a good relationship with the local community.”
