Microsoft simultaneously announced plans for the
construction of the data centres, which will be powered by renewable energy,
with their location chosen to allow for recycling of heat created from the
cooling of computer servers.
District heating is widely used in Finland, pumping hot
water through pre-insulated underground pipes, and has traditionally relied on
fossil fuel sources.
Fortum operates a system of underground pipes stretching 900
kilometres and serving 2,50,000 users in the Helsinki metropolitan area. Once
completed, the data centres will account for 40 percent of the system's heat
supplies, the two firms said.
Fortum said its investment for the heat capture side from
the data centres was estimated at 200 million euros, with expectations this
would cut some 4,00,000 tonnes of CO2 emissions annually.
Microsoft declined to say how much it would invest in the
centres. It estimated however that it would initially require some 400-500
gigawatt-hours (GWh) of renewable energy per year, which it said was comparable
in scope to other local industries such as a paper or pulp mill.
Microsoft plans to buy the electricity via one or several
long-term power purchasing agreements (PPA), although no supplier has yet been
selected, the company told Reuters.