Data centers, the buildings and campuses that house computer servers and related data-storage equipment, generate massive amounts of waste heat, which is usually released into the atmosphere. However, that’s not the case for a data center in the UK, which is now using its waste heat to power a public swimming pool in the city of Devon.

Even small data centers produced a lot of heat, so a group of researchers thought they could use this instead of simply wasting it. The principle is straightforward: computers at the data center are surrounded by oil, which then captures the heat produced by the machines, and is then pumped into a heat exchanger that can raise the temperature in the pool to around 30 °C for 60% of the time, the BBC reported.

The data center is run by the start-up Deep Green, founded by Mark Bjornsgaard, which uses computers to power artificial intelligence and machine learning. The founder told the BBC he’ll also refund the leisure center’ electricity costs for running the heat exchanger. He has requests for another seven pools in England to be part of the scheme.

Sean Day, in charge of the leisure center that has the swimming pool, told BBC they were expecting their energy bills to reach $100,000 this year. The partnership with Deep Green allowed them “to reduce the costs of what has been astronomical over the last 12 months,” he said, claiming their “energy and gas prices have gone through the roof.”

In 2022, an NGO industry association in the UK, said its members were facing bills up to 200% higher than in 2019, with costs expected to increase up to 240% this year. Jane Nickerson, the governing body for swimming in the UK, told the BBC that it was good to see the pools “embracing innovative solutions” amid the higher energy costs.

Data centers and energy usage

Data centers are estimated to account for 1% to 2% of global electricity usage. The percentage is higher in Europe, where it accounts for 3% of all electricity. They produce a lot of waste heat, some of which could be repurposed to help homes and businesses. The possibility has now become more viable with the high energy bills due to the war in Ukraine.

Amazon, Apple and Microsoft have started connecting, or announced plans to connect, big data centers to district heating systems in Ireland, Denmark and Finland. Alphabet is reviewing similar opportunities, while Meta is ahead of the game, recovering excess heat from its data center in Denmark since 2020 – with plans to expand this further.

Legislative efforts in Europe are also encouraging the recovery of heat from data centers, such as the Energy Efficiency and the Renewable energy directives. New data centers with a total energy input exceeding 1 MW will have to recover excess heat and deliver it to the network unless they can prove it’s not technically or economically feasible.

Data centers are usually cooled with air, and the hot air they release isn’t always as hot as needed by municipal heating systems – which then requires heat pumps to be installed to warm the air. Also, residential buildings and offices only need the heat half the year or less during winter, which potentially makes most of the production go to waste.

Despite these challenges, the pressure is mounting on tech giants to run their data centers more efficiently. In Denmark, for example, officials asked Apple to connect its 485,000-square-foot data center to the local heat network, which the company finally agreed to do. Similar discussions are taking place in Uruguay with a data center from Google.