Hidden deep within the bedrock of a massive cave underneath popular orthodox Christian landmark Uspenski Cathedral, the planned data center -- which will be comprised of hundreds of computer servers -- is expected to emit substantial amounts of heat.
That heat will then be captured and channeled into the city's district heating network, a system of water-heated pipes that are used to warm homes in the city.
How's that for renewable energy?
The new data center is due online in January and is intended for use by local IT services firm Academica. It's a novel way of using the power consuming nature of data centers -- known to be energy hogs -- for good.
Data centers themselves have recently been under scrutiny for their expense, which can account for up to a third of a corporation's total energy bill. Together, those data centers add up: the server farms run by Google alone use 1 percent of the world's energy, and demand for more power only grows each year.
Temperature is part of the problem. Often, more power is used to cool large data centers than actually compute with them.
What's more, all that power consumption leads to emissions: data center emissions of carbon dioxide total one-third the amount that airlines produce, according to a Reuters report, grow 10 percent each year.
That's enough emissions to rival entire nations such as Argentina or the Netherlands.
The new Helsinki data center promises to use half as much energy as the average data center, and its capacity to heat homes will be the energy-producing equivalent of one large wind turbine -- about 500 large homes.
The data center is expected to shave approx. $561,000 per year from Academica's annual power bill, said sales director Pietari Päivänen.
Oh, and the significance of the church above it? Security. The cave used to be a World War II-era bomb shelter for city officials to escape from Russian air raids.