Video: Helsinki's Underground Data Center

CNN's Richard Quest looks at Helsinki's underground city- a vast network of man-made tunnels and caves that houses much of its industrial infrastructure, including coal storage and a huge district heating and cooling systems. One of the newest tenants of the city's subterranean section is a new data center developed by utility Helsingen Energia and ISP Academica. The 2 megawatt facility is located 30 meters below the Uspenski Cathedral, a historic church. The data center uses cold sea water in its cooling system, while the waste heat produced by the servers is piped via a heat pump into the district heating network to heat Helsinki buildings and the residents' domestic hot water. When the hall is full of computers, the heat it produces is enough to heat up to 500 large single-family houses in Helsinki. The data center is featured at the 3:30 mark in this video, which takes a broader look at the city's underground infrastructure. More on the data center after the video.

Juhaa Sipila of Helsingen Energia discussed the underground Helsinki data center at The Uptime Symposium last spring. H estimated that the 2 megawatts of capacity can operate at an annual savings of $200,000 from an equivalent above-ground data center in Helsinki. Sipila has a larger vision for how underground data centers could support Helsinki's district heating system.

"Eco-efficient computer halls could really save significant amounts of primary energy and at the same time recover wasted heat for recycling," said Sipila. "It is perfectly feasible that a quite considerable proportion of the heating in the capital city could be produced from thermal energy generated by computer halls. When it’s cold outside, you need a lot of heat to warm the house. But the data centers were putting all of this heat into the atmosphere."

For more on underground data centers, check out these features: