Microsoft data centre to heat homes

Across the world, massive energy-intensive data centres are whirring away as the backbone to the digital revolution. They power our smart building systems – integral to cutting real estate’s emissions – yet they also release a steady stream of wasted heat. But what if we could harness that waste?

That’s the thinking behind Microsoft’s collaboration with European energy provider Fortum. The partners last week announced several new data centres near Helsinki, Finland that transfer heat from the server cooling process into homes in the city’s metropolitan area.

Powered by 100% renewable energy, the data centres will become a source of clean heat for the city.

Though not the first to channel data centre heat into homes, the partnership is significant for being the largest of its kind in the world. Unlike other similar projects, the location of the data centres was chosen specifically with heat recycling in mind, Fortum says.

Sustainable solutions can be simple

Data centres give off a lot of excess heat: Germany’s Network for Energy Efficient Data Centers, for example, estimates that the country’s data centres convert about 13bn kWh of electricity into heat, releasing it into the atmosphere, unused.

While wasted heat itself is a marginal contributor to climate change, the energy needed to heat homes does have a significant impact. In the US, 20% of emissions come from heating, cooling and powering homes. Redirecting waste heat from data centres that use renewable electricity to our homes could cut overall emissions.

The Microsoft data centres in Finland will connect to Fortum’s existing district heating infrastructure of 900km of underground pipes connected to 250,000 users around Helsinki in cities like Espoo and Kauniainen. Once the data centres are up and running, about 60% of the area’s heating will come from recycled waste heat (though this includes other sources as well, such as purified water waste).

Fortum expects the data centres to reduce carbon emissions by 400,000 tonnes annually in the area.

“Sometimes the most sustainable solutions are simple ones: by tapping into waste heat from data centres, we can provide clean heat for homes, businesses and public buildings in Espoo’s and the neighbouring communities’ district heating network in Finland,” Markus Rauramo, president and CEO of Fortum, said when the Microsoft partnership was announced.

Other heat capture projects

Bunhill 2 Energy Centre, Source: London Borough of Islington

Facebook | In Odense, Denmark, the social media giant – now Meta – installed two large server halls that feed surplus heat into the city’s district heating network in 2019. With a third site announced a year later, the data centres have the capacity to heat about 11,000 homes.

London Underground | In 2020, the London Borough of Islington launched an energy centre that extracts warm air from London Underground tunnels and pumps it into the neighbourhood through a network of underground pipes. At the time, Bunhill 2 Energy Centre could provide heating and hot water to 1,350 homes, a school and two leisure centres in the borough.

Stockholm Data Parks | A collaboration between the city of Stockholm, energy provider Stockholm Exergi (part owned by Fortum) and several other stakeholders, the project’s goal is to put a) make Stockholm a cheap and attractive place for data centre operators and b) recycle all the heat they generate into homes. Eventually, SDP hopes to supply 10% of the Swedish capital’s total heating demand.

Could data centres heat homes anywhere?

There are two key reasons why the Nordics are home to major heat recovery projects. First, the grid is green. According to Fortum, about 80% of the electricity in the Nordics is carbon-free, which means powering data centres is much more environmentally-friendly than in parts of the world more reliant on fossil fuels.

Second, district heating networks are common in major cities in the region. Not only do they remove the need for individual boilers in people’s homes, they also provide energy infrastructure for data centres to tap into and sell their excess heat to – as Microsoft will do in Helsinki.

But data centres – and other buildings with a lot of wasted heat – could help reduce emissions in heating around the world, especially as grids become greener. Demand for these digital powerhouses will continue to rise, and so will demand for greener homes.

“If we are to limit global climate warming to 1.5°C as required by the Paris Agreement, we need innovative thinking to drive change at higher pace and bigger scale,” says Nebahat Albayrak, Fortum’s SVP of corporate affairs, safety and sustainability.

“This investment in the data centre region is a flagship example of climate action and circularity. The project is the first of its kind of this size, but we hope to inspire further development in the use of waste heat to deliver clean energy.”