Fortum’s Swedish subsidiary Fortum Värme and Sweden’s oldest internet service provider Bahnhof are to jointly build a 20 MW facility designed to pipe excess heat to Stockholm’s district heating network.  

When it comes online in 2017, the new Green Hub Stockholm – a data centre optimised for heat recovery – will join the ongoing Data Centre for District Heating (DCDH) project, to which three of Bahnhof’s data centres are already connected.  The project is run by the Fortum-Bahnhoff joint venture Elementica.  

The Green Hub will use seawater for cooling, while its excess heat is pumped into the district heating system through a series of heat pumps. It will run on 100% renewable energy, the firms said.  

Selling data centres’ waste heat is good economics, the companies believe. “This promises to provide us with exceptional OPEX savings through the sales of heat,” said Bahnhof CEO Gustav Bergquist. “The heat represents value. It’s this value that will allow us to provide a very cost-efficient and completely sustainable data centre operation.”

Fortum’s district heating network supplies 80 per cent of Stockholm’s homes, shopping centres and offices.