UK puts £90M into heating homes with waste heat from datacenters

The UK government is putting £90 million ($119 million) into heat networks that reuse excess heat from datacenters and factories to warm homes. According to the Department for Energy Security and Net Zero (DESNZ), more than 750,000 homes will get cheaper heating through the scheme.

A mega project under the Thames

The programme includes a "mega heat project" to distribute hot water through a tunnel under the River Thames. It is backed by £41 million ($54 million) and, the department claims, will supply 650,000 London homes alone with "clean heat", cutting the capital's reliance on gas. Similar district heating schemes have run for decades in Copenhagen, Amsterdam, Vienna and Berlin.

Until the tunnels exist, DESNZ says electric barges will carry hot water 25 kilometers (15 miles) along the Thames each day from a waste plant near Bexley. A DESNZ spokesperson told The Register the £41 million covers only the barge stage, expected to start in 2028, while the tunnels are hoped to run in the 2030s; no cost estimate for the tunnel work has been published.

Questions over efficiency

Whether datacenter waste heat is efficient enough for home heating is open to question. The Uptime Institute has noted the temperature is typically too low, so a heat pump is needed, and that uses more energy. A 2024 report from trade association TechUK said the newest fifth-generation heat network designs can work with a datacenter's lower-temperature output, but most UK systems are third-generation, with lower efficiency and higher carbon intensity.

Public support and expert caution

Despite those doubts, polling by EnergiRaven, a firm advising on energy efficiency, found about 60 percent of British people think planning permission for datacenters should be conditional on them supplying excess heat to local homes and businesses. 62 percent said they would be more supportive of a project in their area if it made that commitment. The firm wants all new server farms above 1 MW to include heat-sharing infrastructure.

Alan Howard of analyst group Omdia told The Register that district heating is "a win for any community" and can cast datacenters in a positive light, as some communities are hesitant to embrace them. But he added it is too early to call the plan a project: "at this stage it is a concept". He warned the effort could face a long, messy timeline, and that construction costs could easily balloon.

Other networks getting funding

Other schemes receiving investment include an extension to an existing system in Solihull in England's midlands, a project at Marble Arch in London serving Oxford Street offices, homes, hotels and businesses, and one in Bexley and Greenwich that may serve up to 100,000 homes when fully built.