Maybe you’ve started taking long-distance trains in the name of the climate. Or perhaps you’re minimising your carbon footprint by choosing secondhand over fast fashion. But completely cutting your emissions in every area of your life is difficult—some emissions, such as those released by heating our homes, are a necessity rather than a luxury. And with 13 percent of the EU’s total emissions coming from heating and cooling buildings, our need for warmth is rapidly warming our planet.
Meanwhile, there is an ever-growing source of heat that we can use to keep us warm: the waste heat released from cooling data centres. As our lives become increasingly digital, data centre emissions are booming. Not great for the planet but if we can divert their excess towards our buildings, then at least we could reduce heating emissions. And reusing data centres’ heat doesn’t stop at buildings. From swimming pools to fish farms, several innovative solutions ensure the heat generated by our digital lives doesn’t go to waste.
CO2 emissions from data centres are an increasing threat to the planet
The permeation of digital tools in every area of our lives, as well as the increasing dominance of AI, means that CO2 emissions from data centres are on the rise—and show no sign of stopping. Power consumption from data centres is likely to more than double by 2030. We asked Dr Ralph Hintemann from the Borderstep Institute about the threat of data centres to our planet—and what action we can take to mitigate their impact. Read the full interview here.
The projects pioneering waste heat re-use
At 2,860 terrawatt hours per year, the EU’s excess heat (from sources including data centres and supermarket fridges) almost exactly corresponds to its demand for heat in residential and public buildings. In Dublin, Amazon Web Services’ data centre is providing heat for public, commercial and residential buildings, saving 1,400 tons of CO2 emissions a year. Meanwhile, Stockholm strives to use data centre waste heat for 10 percent of its heating, with three data centres already keeping thousands of households warm.
As for swimming pools, British company Deep Green uses data centres to heat local indoor pools, saving leisure centres costs as energy bills soar. And, in order to meet sustainability goals, the indoor pool built for the Paris Olympics was warmed by nearby heat sources, including the Equinix data centre.
It’s not just humans that data centres are keeping warm. With lobsters growing optimally in 20-degree sea water—the exact temperature of water that has cooled data centres—reusing waste heat is a no-brainer. In Norway, data centre company Green Mountain took advantage of this serendipity by warming water in a nearby lobster farm with their excess heat. Another of their projects is a trout farm that not only reuses waste heat but also returns cooled water to the data centre so it can be used to cool down servers, achieving true circularity. Further farming projects include heating greenhouses with waste heat, an initiative that’s active everywhere from Quebec to Finland to India.
How can we ensure a green digital future?
Growing e-waste, carbon emissions from AI, data centre water usage—is rampant digitalisation compatible with a healthy planet? Our latest project explores how digital tools and services can be developed with sustainability in mind.
Matching data centres with sources in need of heat can be challenging
Although there aren’t concrete figures on just how many data centres are reusing their waste heat, we do know that the majority haven’t yet jumped on the bandwagon. But why is that the case? Is it really so complicated or costly to connect a data centre with a source in need of heat?
We spoke to Ralph Hintemann from the Borderstep Institute about the viability of such projects. He pointed out that waste heat reuse is mostly possible when building new projects—it’s rarely an option to adapt existing data centres. This is because, with a new project, developers can take planning into account from the beginning, whereas “replacing an existing heat supply is much more complex”. District heating networks operate at higher temperatures, so the heat from data centres must be increased before it can be reused, which makes reuse hardly worth it. Meanwhile, data centres must be located near the site in need of heating and finding an appropriate recipient in the vicinity of an existing data centre can be tough.
Geographical location also plays a role in whether it’s worthwhile to reuse waste heat. Northern Europe may be an ideal location for such developments but “in Spain or Greece, for example, prescribing the use of waste heat when the outside temperatures are rarely lower than the temperatures in data centres does not make much sense.” The distance between a data centre and the project requiring waste heat is another challenge, as is cost. It’s not always clear who in the partnership should be funding the often expensive building process.
Matchmaking for data centres
A data centre and a building that requires heating are a match made in heaven. But starting these partnerships can be challenging. The Borderstep Institute’s project DC-HEAT uses AI technology to discover the most ideal locations for data centres in relation to local heating networks. Find out more about the project here.
“It’s currently a matter of implementation”
One positive is that we don’t need to spend years innovating to get such projects off the ground. Hintemann assures us that as the technology already exists, “it’s currently a matter of implementation.” Germany has introduced new regulations that require data centres that begin operations in 2026 to achieve an energy reuse factor (ERF) of at least 10 percent. By 2028, the necessary ERF will be 20 percent. “At the EU level, there are no fixed requirements for this yet,” Hintemann adds, “but they are in development.”
With our digital consumption showing no signs of slowing, data centres will continue to meet the demands of our online lives, releasing waste heat as they do so. As Hintemann says, “The use of waste heat from data centres is an issue that will play a major role in Germany and Central Europe in general in the future.”
