Google Hamina data center

The story

Stora Enso stopped paper production at its Summa mill on the Gulf of Finland in January 2008, and in 2009 Google bought the buildings and most of the site for about EUR 40 million. The mill's 1950s seawater tunnel became the cooling intake: Baltic water runs through a heat exchanger, then is mixed with more seawater before it flows back, and Google said the halls would need no chillers. The first data centre opened in 2011; a sixth was being built by 2020 and a seventh was announced in 2024. Waste heat now goes to Hamina's district heating network, which the local utility expects to cover about 80% of annual demand. Google puts its investment in the region at EUR 3.5 billion.

Notable

• Seawater reaches the site through a tunnel built for the Summa paper mill in the 1950s; in 2011 Google said the facility would run without chillers.
• Before it returns to the gulf, warmed water is mixed with fresh seawater in a 'tempering building' so it goes back closer to the inlet temperature.
• Stora Enso sold the buildings and most of the Summa mill site to Google for about EUR 40 million in February 2009.
• Google reports a trailing-twelve-month PUE of 1.09 for Hamina in Q2 2026.
• Under a 2024 deal, Hamina's waste heat goes free of charge to Haminan Energia's district network, expected to cover about 80% of its annual heat demand.

Expansions

• 2009: Google buys the buildings and most of the closed Summa paper mill site from Stora Enso
• 2011: first data centre opens in the converted mill
• 2012: second hall announced (about EUR 150 million)
• 2020: sixth data centre under construction, due in 2021
• 2024: seventh data centre announced; offsite heat recovery deal signed with Haminan Energia