Audio Transcript:

Computer servers at big data centers around the globe generate a lot of heat. A company in Finland has figured out a way to capture that wasted energy and use it to heat homes. The World's Technology Correspondent Clark Boyd has the story from Helsinki.

DAVID BARON: Finland used to be one of Europe's poorest countries. Now it's a hub for high-tech innovation. The big name of course is the cell phone company, Nokia. But there are many Finnish companies that run large data centers. These are essentially huge rooms of servers that computer companies around the world use to store their data. Now some of these servers are being put to a surprising use. Here's The World's Technology Correspondent Clark Boyd.

CLARK BOYD: This story starts in a bomb shelter deep beneath downtown Helsinki. Well, it used to be a bomb shelter. During World War II, the Helsinki City Council held its meetings down here, dozens of feet below the largest Russian Orthodox Church in Western Europe. It's essentially two giant, cave-like rooms carved out of solid bedrock. These days, the space is being used for something very different. A Finnish IT company called Academica is busy installing racks for servers.

PIETERI PARVINEN: So we're actually here now at Academica's data center, which is probably the world's most eco-efficient data center.

BOYD: Pieteri Parvinen of Academica explains that data centers do more than just store bits of information. All those machines also give off a lot of heat. They need to be kept cool. And that's where something called district cooling comes in. You see, about 75 feet below the server room is a series of huge water pipes. They carry cold water, usually Baltic Sea water, throughout Helsinki. That water is used to cool homes and apartments. Or in this case, a room full of running computers.

NIKO WIRGENTIUS: And then we realized, hey, there are a lot of surplus heat related to these kind of a large scale server rooms.

BOYD: Niko Wirgentius is with a city-owned company called Helsinki Energy.

WIRGENTIUS: And then we realized that that's the resources that otherwise would be wasted or unused. So we decided to transfer that surplus heat to the heating network. This is a really simple idea. It's not rocket science. There is two pipelines. One's come from our production plant and comes here to server room. It cools down all the servers and then the warm water comes back to our production plant to heat up the houses and domestic hot water.

BOYD: Estimates are that these two server rooms can heat 500 homes for a year, even in Finland's brutal winters. And using recycled heat, the thinking goes, will also reduce some of the need for fossil fuel. For Academica, the projected cost savings is substantial, says Pieteri Parvinen.

PARVINEN: Actually, we have made calculations that our electricity bill will be around 180,000 Euros lower than in a traditional data center.

BOYD: That's around $240,000 in savings just from a small data center. The savings, Parivenen says, can be passed along to customers. Harvesting heat from data centers seems to be catching on here in Finland. A similar project is under way in Espoo, a high-tech hotbed just outside of Helsinki. Ari Karpinnen is with Tieto, the IT company involved in Espoo's green data center. He says the IT industry is responsible for about 2 to 3 percent of global CO2 emissions. That's about the same amount as the airline industry. And a lot of people, he says, would like to see a greener IT.

ARI KARPINNEN: Customers are asking that, how do we see this green IT? And what are our plans? What is our policy? Pretty hot topic at the moment.

BOYD: Other countries are paying attention to what Finland is doing. Helsinki Energy and Academica recently won a 2010 Green IT award for their data center design from the US-based Uptime Institute. The two companies already have another eco-friendly data center in the works that will be ten times larger than the one in the former bomb shelter. And they're looking for ways to make at least some of the technology work in cities that don't use large-scale water systems to heat and cool their homes. For The World, this is Clark Boyd, Helsinki.