Waste heat from a Google data center in Finland will be used to warm homes and businesses as part of a €1 billion ($1.1bn) investment in the facility.

The heat recovery system at the data center near the city of Hamina, in the south of Finland, is the first project of its kind Google has undertaken, the tech giant said.

It will see heat generated at the data center routed into a district heating system operated by energy company Haminan Energia, which serves homes, schools, and public service buildings in the area.

The number of properties connected to the network has not been disclosed, but Google said heat from the data center will provide 80 percent of the network’s requirements when the heat recovery system comes into operation next year, and that it will be free of charge.

Ilari Soosalu, mayor of Hamina, said: "Google and the city of Hamina have a long and flourishing history together. Google is an excellent example of a company with strong sustainable future orientation. It feels good to be the hometown of Google in Finland."

Google bought its Hamina data center in 2009. It is built on the site of the former Summa Mill and uses sea water to cool its servers.

The data center has been upgraded several times over the last 15 years, and in 2022 Google purchased 50 acres of land next to the data center to accommodate a possible expansion.

The €1 billion ($1.1bn) investment announced this week will see the number of staff working at the site grow to 500 over the next months. Google has not disclosed what impact, if any, the investment will have on the data center’s capacity.