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Public Radio's Environmental News Magazine (follow us on Google News)

Swedish Body Heat

Air Date: Week of
Stockholm's T-bana subway system. (Photo: Flickr/James Cridland)

The body heat from the hundreds of thousands of commuters who use Stockholm’s Central Station will be harnessed to heat a nearby office building. Deutsche Welle Radio’s Aarni Kuoopamaki reports.


GELLERMAN: And now another story about harvesting waste heat – this time in Stockholm, Sweden, where the average winter temperature is below freezing. Commuters in Stockholm’s Central Station bundle up to fend off the frigid clime. Now, there are plans to use the heat their bodies generate in the station to warm a nearby building. Deutsche Welle Radio’s Aarni Kuoopamaki has our report.


KUOOPAMAKI: Two hundred and fifty thousand people arrive at Stockholm Central Station every day. Mostly, they are in a hurry. Since the Central Stakhun, as the locals call it, connects commuter trains to the municipal subways system. As the travelers race from one platform to the other in their thick winter jackets, their skins work like a giant radiator. One breath has a volume of about half a liter. Two hundred fifty thousand breaths - that’s taking account of only one for each commuter in every train - amount to about 135 cubic meters. And this is more than just air; it’s energy. And energy is money, explains construction manager Karl Sundholm.

SUNDHOLM: This building doesn’t really need heating because of all the people in here. We’ve got plenty of heat here that we actually just get rid of it out in the air. So instead of getting rid of that, we pump it over to that building over there, ja? See it there?

KUOOPAMAKI: He’s pointing to a flat gray building squatting above the railway tracks.

SUNDHOLM: You can see that all their windows are taken out and we’re beginning to tear it down from the ceiling.

KUOOPAMAKI: It’s not really beautiful I must say.

SUNDHOLM: No, it’s a quite ugly one. It’s actually been named one of Stockholm’s ugliest houses. It’s like 25 years old but it’s got very bad isolation and it’s very low to the roofs and so it’s a bad building. We have tried to figure out how we could use it in other ways but—no way. We found out that the best thing is to tear it down and build a new building up.

Stockholm's T-bana subway system. (Photo: Flickr/James Cridland)

KUOOPAMAKI: The new commercial building will be known as the Kundt’s brew house. Karl Sundholm works for Jernhusen, a state-held private company, which owns the Swedish railway stations and some of the buildings attached to them. For example, the Kundt’s brew plat. The principal of using hot air to generate energy is not in itself new. Warm air is collected and its energy transformed into hot water by a heat exchanger. But in this case, warm air produced by human bodies will be pumped to another building through a pipe several hundred meters long. The system’s simple.

SUNDHOLM: It’s just a couple of pumps and some pipes. There’s no special things needed. No rocket science, as somebody said.

KUOOPAMAKI: The recovery of body heat will provide about 15 percent of the heating and energy needed for the 13-story, 40,000-square-meter Kundt’s brew house. The building will have a parking lot and a hotel underground, shops at street level, and office space on the top. It will be finished in 2010, but Karl Sundholm already sees the ecological system as a way of attracting tenants.

SUNDHOLM: This could be something that the ones who rent these offices could use as a marketing thing for themselves and for their customers. We’re sitting in this house and we don’t use as much energy that we would if we sat in another house. So, we’re going to try to help the offices to work with their environmental issues as well.

KUOOPAMAKI: Everybody is supposed to profit from the energy recycling, not the least the environment. Therefore, the commuters providing the energy seemed more than happy to contribute their body heat free of charge.

MAN: To use people’s heat to heat up a building? Sounds nice.

MAN 2: Ah, that’s a good one! Environmentally friendly, no?

WOMAN: Two hours ago I was watching a movie about global warming so I think that’s a good idea.

MAN 3: Every part counts, doesn’t it? Just every bit helps.

WOMAN: I mean, you get it for free, so yeah, why not?

MAN 3: I think that’s a very innovative and creative solution and it’s cost effective and also it doesn’t create much of an adverse effect to the environment at all so I would say it’s a pretty good way to go. As long as the government is not taxing us for that!

KUOOPAMAKI: From the Central Stakhun, it’s only a few hundred meters to the Swedish Ministry of the Environment. Political advisor Hanes Bury offers us visitor water from the tap. The minister has abandoned bottled water because its transport causes unnecessary carbon dioxide emissions. It’s merely a small gesture among a multitude of measures to protect the climate. All in all, this strategy seems to be successful, explains Bury.

BURY: Sweden is one of the few countries in the Western world that’s managed to decrease our emissions of carbon dioxide meanwhile the economy has grown. So we have managed to decouple emissions and economic growth.

KUOOPAMAKI: In Sweden, the yearly amount of emissions can vary quite a bit, depending on the winter. In the cold northern climate, heating takes up a lot of the total energy consumption. Therefore, the Swedes rely on district heating in urban areas, where heat is distributed to the homes from a single energy efficient plant. Body heat was first recycled in prototype houses, then in public buildings. This latest step takes it from one building to another. But the Swedes, says Hanes Bury, want to do more than that.

BURY: On a global scale we only account for 0.2 percentage of the carbon emissions but one of the ambitions of the Swedish government is to establish good examples and good technologies for technology transfers to other countries. For example, if we can use our examples in district heating and renewable fuels and use them in, for example, China, where they build a new coal plant every week, then we can maybe take part in helping out with a solution on the global level. It’s not enough just to solve the problems at home. We have to help with global solutions as well.


KUOOPAMAKI: Knowing this, commuters in Stockholm Central Station can sit down to relax in the train, sweaty but happy to have done a good deed for the environment.



Deutsche Welle Radio’s “Living Planet”


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