Tag archives for sustainable cities

Can underground water cool Stockholm’s city houses?


The house to the right could be the first one by Sergels Torg to be heated and cooled by undergreound water reserves. Photo: Vasakronan.

We don’t often think about what’s under our feet when walking around in the middle of a city, but in the centre of Stockholm there is actually several aquifers – large underground layers of water-bearing rock or gravel – that can be of great use. Since water has an ability to store heat or cold, these aquifers work a bit like a thermos.

The idea is more or less to pump up the cold water at summer to cool buildings above ground. This makes the water temperature rise a bit. Then the water is pumped back down into the ground and stored until next winter, when it can be used for heating buildings. This gives about three or four times more energy than what is used for pumping the water up and down.

Vasakronan, which is a large property company, hopes to be able to use this technology for example in one of the big high-rise buildings just by Stockholms main square, Sergels Torg. According to Vasakronan’s head of development and environment, this system can save energy equivalent to the energy use of 450 detached houses.

I must confess that to me it’s a bit of a mystery how only a few centigrades of difference in the water’s heat can make this big a difference, and how it can spend several months under ground without losing the heat… But in an article about aquifers in the construction industry journal Byggindustrin, Olle Andersson who is a professor in energy storage at the University of Lund stated that this is actually a technology where scientists actually have failed to find any disadvantages.

Greening a small town


The architect students' own image of a sustainable Alingsås.

Earlier I’ve written about the 25 architect students from Chalmers University of Technology who have been concentrating on how to turn the ordinary small town Alingsås into a place that will work and prosper without fossil fuels.
Now the time has come for the students to present their ideas, and yesterday they met local politicians, the Transition Alingsås group and “ordinary” inhabitants in a crowded assembly hall.

All their projects are presented on their website (some of them in English) and several of them focus on the importance of producing food locally in a world where greenhouse gas emissions must decrease and energy will be a more expensive resource.

One of the studies that I like particularly is made by Elin Erlansson, who has sketched the first steps of how to make Alingsås more self-sufficient on food. Her idea is to engage the inhabitants to start growing more food themselves, individually and collectively, and to create a food centre in the middle of town just by the train station. In this centre the locally and regionally produced food would be gathered and then further distributed to consumers coming to the grocery shop by bike or by foot, or transported to people’s home areas with public buses that will anyway make their way through town.The centre also houses a restaurant serving locally produced dishes and Elin discusses the possibility of using a local currency to facilitate these local supply chains.

Another project work written by the students Hajir Latifi, Virginie Ducournau & Daniela Farias (in English) target on how the city centre has been flooded with cars and how this could be changed, making Alingsås a town for pedestrians and cyclists.

It all sounds very nice and when you think about it, it’s easy to start wondering why these aren’t ideas always applied: After all, having towns made for the people living there, making sure they will have food, clean water and encouraging their engagement in the local environment sounds like a good idea, doesn’t it?

Warming Swedes with body heat

This winter has so far been one of the coldest in Sweden in a long time. In December, when temperatures were the lowest for about 150 years and Sweden at the same time had a standstill in some of our nuclear reactors, electricity prises rushed up to record levels.

This was of course not a very happy situation for those who heat their houses with electricity. On the other hand, there are plenty of more efficient ways to do it. One is to use the excess body heat of people in motion. This is done in the Kungsbrohuset building in central Stockholm, which is partly heated by the excess body heat from the 250 000 persons flowing through the central station building every day.

Now the BBC has made a feature  about how this works. It’s fascinating that something most people don’t even think about like body heat can be harvested like this, but as every person generates about 100 watt it does add up…

Vertical farming for future cities


Could vertical greenhouses help cities meet future food challenges? Image: Plantagon International.

“Far from lagom” (lagom meaning something like “just enough”, or moderate) is the slogan of the municipality of Botkyrka in the outskirts of Stockholm. So when they started thinking about urban food safety the idea that came up was also far from lagom: A sphere-shaped vertical greenhouse, about the size of the Stockholm landmark Globen.

But why a giant glass ball filled with vegetables? United Nations expects that the world’s cultivable area won’t be enough to feed a growing global population. At the same time an increasing part of this population lives in cities and transports will be more expensive because of a peaking oil production, so why not produce the food directly where it’s needed?

According to Hans Hassle, CEO of the company Plantagon that makes the sphere greenhouse, this type of greenhouse can get up to four times as productive as an ordinary one, providing as much as ten times the cultivable area compared to the surface needed for the building itself.

Now the Swedish Delegation for Sustainable Cities have granted the Plantagon project 150 000 SEK (about 21 500 USD) to investigate if a greenhouse like this might be something for Botkyrka. The municipality sees it as a way of renewing the million programmes in this area. So who knows, maybe we’ll have a new – food producing – landmark in Stockholm in a few years?

More resilient cities


Ideas for a Shanghai beyond oil in the Urban Planet Atlas

The sustainability discussion is often filled with difficult terms. Most of them can be avoided, but one that I actually find useful is the term resilience.

Resilience, in a simplified sense, can be said to be the elasticity of for example a society or an ecosystem. More exactly it refers to “the capacity of a social-ecological system both to withstand perturbations from for instance climate or economic shocks and to rebuild and renew itself afterwards”. Yet anoother way to describe it: As we cannot prevent all types of shocks, we have to be able to cope with them.

Today resilience could often be better. One example of that is how the effects of hurricane Katrina were much more severe because of a weakened wetland that couldn’t absorb the big waves. Another example is, as I mentioned in my last blog post, how vulnerable cities are if incoming food transports would stop for one reason or another.

One of the places where resilience is specifically studied is at the Stockholm Resilience Centre. This centre has now developed an online platform for sustainable urban development, which will be launched at the Expo2010 in Shanghai.

The idea is to point out the close connections between social and natural systems, and the fundamental role ecosystem services play for human wellbeing.

An upgraded version of the Urban Planet Atlas, as they call it, will be launched in Shanghai in October, but it is already possible to try it online. Shanghai itself is one of the example cities which are already put into the atlas. Check under “Solutions for Sustainable and Resilient Cities” and see how students at the Royal University College of Fine Arts in Stockholm has envisioned a Shanghai beyond oil.

Read more about what resilience is at the Stockholm Resilience Centre.

Also read their and the organisation Albaeco’s interesting blog Sustainable Development Update.

Read more about Shanghai Beoynd Oil.