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Archive for November 2015

The houseboats of Hamburg

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Houseboats on the leafy Eilbek Canal

Houseboats on the leafy Eilbek Canal

Hamburg’s real estate is not all land-based; there are some houseboats, too. Surprisingly few, actually, given the extent of shoreline along rivers, lakes and canals. This is a water city; locals boast that Hamburg has more bridges than Venice and Amsterdam together. Maybe the lack of houseboats is due to the fact that many of the canals are tidal, and the Elbe itself can be fairly temperamental.

Walking distance to downtown, yet this is your backyard (on the Eilbek)

Walking distance to downtown, yet this is your backyard (on the Eilbek)

Nonetheless, there are houseboats to be found. The best known may be along a stretch of the lovely Eilbek canal. In 2006, the city issued a design challenge called “Living on the Water”. The prize winners would be granted the right to their own berths, and would be picked for innovative solutions to the constraints: canal navigation and bridge access was had to be unimpeded, draught had to be 80 cms or less, etc. As a result, there are now ten houseboats moored along the canal; these are the winners out of over 400 entries, attesting to the popularity of the idea.

Your neighbours across the canal.  Despite the leafyness, it is a very urban area

Your neighbours across the canal. Despite the leafyness, it is a very urban area

Along the Eilbek

Along the Eilbek

 

 

 

 

 

 

 

 

 

 

 

One of the winners, architect Amelie Rost, says it’s not all fun and games. The biggest downside is the additional maintenance required. But Rost says it’s worth it; one feels more connected to nature, feeling the waves. She adds that she sees this as a viable option for cities.

The process for developing floating houses —and cities, who knows?—is just starting in Hamburg and Germany and it’s not always easy. But it’s a great option for developing living space in growing cities, and if cities and their municipalities also think one step further, it could also be an option for creating new urban spaces.

New houseboats have now been built in the Hammerbrook area, an booming office neighbourhood close to downtown; some of the houseboats can be rented as a floating hotel suite. There are also floating restaurants and offices in the same neighbourhood.

Corporate houseboats in the Hammerbrook area

Corporate houseboats in the Hammerbrook area

The idea that floating buildings may be the future of cities has been developed on a larger scale through the IBA’s “Floating Dock”. This was designed as the main office of the 2013 International Building Exhibition, as well as a demonstration centre, a purpose it still serves. The floating three storey building has 1900 m2 of floor space used for offices, conference rooms, a visitor centre, and a café with an outdoor terrace. The building, floating on hollow concrete pontoons, can easily handle the three meter tides of the Elbe. And like all other buildings in the IBA, it is an energy miser, incorporating 25 cms of insulation in its outer walls, as well as solar collectors. But it also uses a feature for which houseboats have an advantage: a geothermal heat exchanger that makes use of the relatively constant temperature of the water over which it floats. The power needed for the heat pump is matched by what the photovoltaic panels on the roof produce, so that during summer the air-conditioning system is completely carbon-neutral.

The IBA Dock

The IBA Dock

So this might be the future. But I have a definite fondness for the past, when houseboats were used by poor but independent and resourceful people. These still exist in Hamburg and have recently been captured in Evgeny Makarov’s beautiful photography series. They’re a bit reminiscent of the shacks on Finn Slough in Richmond. Cryptically, these ones are described as being “in the south side of the city”, which I take as meaning they’re located either along the Bille or the Harburg area, where there are labyrinths of old channels squeezed between the industrial harbour.

One of the houseboats in Evgeny Makarov's series

One of the houseboats in Evgeny Makarov’s series

Another one from Makarov's series.

Another one from Makarov’s series.

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Written by enviropaul

November 22, 2015 at 4:58 am

Trabrennbahn: green infrastructure with impossible soils

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Thr Tranbrennbahn complex on Google view.  Note the solar panels.

The Tranbrennbahn complex on Google view. Note the two ponds in the courtyard and the solar panels on the north side.

Imagine you’re building a residential complex. How do you make sure it doesn’t flood in a downpour?

In the old days, you would just dig storm drains, and let the city sewers handle it. But what if the sewers can’t? Either you get flooded as the sewers back up, or there is a sewage spill into a creek somewhere downstream. Not good either way, and increasingly riskier, as climate change is bringing on bigger storms.

The other approach, one now mandated by many city governments, is to imitate nature. Let rain water infiltrate into the ground, recharge the ground water. This is done with green roofs, infiltration basins, rain gardens and the like (there are many good examples; here’s a good source).

A pond in the Trabrennbahn complex

A pond in the Trabrennbahn complex

But what if the ground refuses to let water through? That was the problem for the developers of the Trabrennbahn complex, which I visited recently. The complex, built in 1998, is made up of 1,160 in separate low-rise buildings, and include a daycare, a school, and an old-age home. District heating with a co-generation system is used for the whole development, and of course the buildings adhered to the latest insulation and energy conservation standards (see below).

Like Lansdowne in Richmond, the complex is built over a former horse racetrack. The developers chose to retain the shape of the track in their design, as can be seen from the air view. This preserved a large internal area, a large green space from which cars are excluded but kids can play safely. The complex is built outside of Hamburg’s dense core; the air photo shows that the area is mostly single-family housing, but well served by transit.

The challenge for the developers: the soils are made of clay or glacial till, so the usual infiltration design could not be used. Instead, excess rainwater is stored on the soil surface. The grounds already had two large ponds inside the tracks; the developers added numerous ditches with weirs, which can hold a substantial amount of water. All that is needed to prevent flooding is to hold back the water a bit, and then slowly release it to the storm drains (or in this case,a creek). So instead of having a sudden rush of water, followed by no water after the storm passes, you get a sponge-like effect, a gentle increase in flow over a longer period.  During the storm, the water level in your ponds and ditches is a few centimeter higher, that’s all.

An example of a storage and drainage ditche

An example of a storage and drainage ditche

It’s simple, and it also makes for a very pretty, inviting landscape, as I could see when I visited. The central open courtyard is mostly lawn, but its surface is bordered by a mixture of un-mowed tall grass, bushes, and copses of trees.  This provides habitat for wildlife, but also breaks the monotony that a plain lawn would create. As it is, there is ample surface for kids to play games. The area has also been landscaped into gentle rises and dips; the landscape is designed so that water collects and flows in the dips, obviously, but the visual effect is that of a pleasing, natural landscape, even if you know it has been engineering from an original pancake-flat topography.

The designers added an extra touch, which may appear minor but makes all the difference: the ponds and ditches are shallow enough to be safe, so no fences or railings are needed (nothing worse than a fence to make a landscape feel hostile). Copses of boxwood trees add visual appeal, but also ensure that geese find the landscape uninviting (geese prefer large open areas). Conversely, few trees were planted next to the ponds where vegetation is thinned so that the open water of the ponds remains visible.

Design is one thing, follow-up is another. This is why I like visiting older environmental sites: have they aged well? Have they lived up to expectations? In Trabrennbahn’s case, the answer is a resounding yes. It was raining when I visited, but scattered toys and scooters showed that the play areas are well used by kids. The ponds and ditches were in fine shape, and no wonder: maintenance crews were on site during my visit, cleaning ditches and drain outlets, something they do regularly. In fact, inspections and maintenance on a regular basis, as well as planned removal of excess algae (which clog drains) was required in order to get a building permit. And so was the requirement of having a limnologist (a lake and river expert) approve the plan; this was all mandated in a legally binding land-use plan. So no sneaky changes after everyone has moved in – smart.

Another air photo of the site

Another air photo of the site

By the numbers:
District heating: natural gas fueled co-generation system, 1.25 MW electrical, 1.6 MW thermal
Drainage: 1,660 metres of ditches, 2,540 metres of waterside, over 200 underground drain pipes
Open ponds: 12,800 m2 of open water from two ponds where brick clay was originally extracted

Details can be found here (in English), here and here (in German).

Written by enviropaul

November 21, 2015 at 2:58 am

Four sustainability thoughts from a birthday lunch in Hamburg

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Dinah took me out for my birthday, a very nice lunch in a neighbourhood restaurant called Drei Tageszeiten. It was great. And we walked there, a good reminder of all that is good about urban living. As I was sipping my wine, a few thoughts came to me. They’re about the food, the drinks, the dog, and the door – and how these can be expression of sustainability as expressed in daily life.

The food
What’s notable on the menu is what’s not found in it. Germans eat seasonally. In the spring you can’t escape asparagus; now they’re nowhere to be found, whether in restaurants or in groceries. Ditto for strawberries, chanterelle mushrooms (everywhere in August), and so on. Dinah and I both had a squash soup: an excellent one, because it is seasonal and made from local produce. What that means is support for local agriculture. It also means that people appreciate the natural cycle of the seasons: the first asparagus! the first apricots! the first local apples! the first new potatoes! They taste so much better when you wait for them. This promotes local agriculture, and often organic agriculture as well.

I ate a filet of Sankt-Peter. One of the great joy of Hamburg is the availability of local fish and seafood, often species I’ve never heard of. I looked up the fish later: its English name John Dory, a widely spread coastal fish often found as bycatch in trawling nets. Unfortunately, in contrast to well-understood organic produce, there is little awareness of sustainable seafood here. My little bit of research shows that the John Dory stocks are probably doing okay, but little is known about them; so as for asking the waiter whether this is from a sustainable fishery, forget it. But man, is this fish ever tasty!

The drinks
Dinah chose a rhabarber schorle. That is something I’ll miss: the juices. And it’s something I wish existed in Canada to help fruit growers: here are juices of every kind, available everywhere. Apple, of course, but also cherry, peach, pear, black current, even rhubarb, Dinah’s choice. The schorle part comes from the custom of mixing the juice with sparkling water (they also do that with beer and wine). It’s excellent.

The downside, from an environmental standpoint, is that Germans buy enormous amounts of bottled water. But fizzers – contraptions that are used to make ordinary tap water sparkling – are becoming popular. I may want to get one for home. I got to like fizzy water, but I still hate the idea of buying water.

The dog
A couple came in the restaurant with their dog, an adorable schnautzer-dachshund cross, who sat quietly under the table. Dogs are everywhere in this country, including public transit. Which means that someone who owns a dog doesn’t have to own a car in order to take their dogs on long walks in forested areas, something commonly done here. Good for dogs, good for their owners, and good for urban planning and transportation.

The door
Leaving and entering the restaurant, I noticed how heavy the door was. In fact, it’s like that much everywhere: doors and windows are heavy because they have good, thick insulating features like triple glazing. I told a local acquaintance that we recently replaced the windows in our Vancouver home to get better insulation. He asked whether they were triple paned; I said no, that would have meant importing really costly windows from Germany. They’re made in Germany, not in Canada. That’s because German policy has created a demand here, so they are manufactured here, common and relatively cheap. But not so in Canada, and since windows come in all kinds of sizes, and are heavy, importing them to Vancouver makes little sense.

Just a few of the things I’d like to see in Canada when I return. C’mon, indulge me, it’s my birthday!

Pumped energy storage (a visit to Geesthacht)

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IMG_8091Often we’re told that renewable energy is not practical without a method to store electricity; after all, it’s not always windy or sunny. I decided to go see an energy storage set-up for myself, in Geesthacht, a small town on the Elbe just east of Hamburg.

Northern Germany is mostly flat, but nevertheless there are small rises. The Elbe has carved some cliffs in these rises. One of these, above Geesthacht, has been used for pumped storage. There, a small reservoir has been dug above the river. It gets pumped full of water from the Elbe below when power is cheap (at night, for instance). When electricity is in high demand (typically, late afternoon for domestic power), water is let out through turbines, generating electricity.

You and I may pay the amount per kilowatt-hour regardless of when we turn on the lights, but it costs much more money to produce electricity when there is a high demand than, say, in the middle of the night. During low demand times, companies rely on so-called baseload power (what coal, nuclear, or large hydro power plants produce day in, day out). But at peak times, special power plants, called “peakers”, are brought on-line to add extra power. In BC, the gas-powered Burrard Thermal plant in Port Moody is an example of a peaker plant; the 900 MW facility is on only about one percent of the time.

An alternative to peaker plants, which produce greenhouse gases, is hydraulic storage, like the one used in Geesthacht. This is just one of fifteen such facilities in Germany (most are in the hillier south). The Swedish company Vatenfall, the owner of the facility, has also built a windmill and a solar farm on site; these two add-ons are also used to pump water uphill.

When I visited, the site was wreathed in mist. The windmill was silently turning, invisible except when right under it. The solar collectors were idle. But the impression of raw power was obvious: the three pipes, each nearly four meters in diameter, were churning the Elbe waters down below, three invisible rivers cascading downhill – and the plant wasn’t even at full power.

the windmill in the mist

The windmill in the mist

Using pumped storage instead of a peaker plant prevents the emission of greenhouse gases, so it has a positive impact on the environment and the climate. It’s not problem free, mind you: pumping large amounts of water in and out of a river can be disastrous for fish entrained in the pipes. The environmental group NABU sued Vatenfall recently for this very reason. And the German government considers that pumping water out of the Elbe is like any other extractive water use and charges for the permit. As a result, the Geesthacht facility is not used to its full potential. And the reservoir is small: it is useful for a daily cycle of energy demand, but it is of limited help for longer storage periods.

What is most surprising, at least to me, is the age of the facility. Was it built in the 90’s, in response to climate change? No. In the 70’s then, during the energy crisis? Neither. It dates from 1958. It was built before any of these concerns rose to the surface – just because it was considered good engineering at the time, when Germany’s (re)industrialization was leaping ahead.

What does that mean for us in BC? We have mountains, and we have water. Hydropower can be fairly finely tuned, if necessary, so (except for Burrard Thermal) we have little need for peaker plants. But water storage has much more potential than this: we could manage our current hydro plants in tandem with wind power, which we are nowhere near developing to capacity in the province. The Peace Valley, by itself, has the potential to generate much more electricity that the proposed Site C plant. And we already have an enormous storage potential for those days with little wind…

Air photo of the site, from the Geesthacht tourism office

Air photo of the site, from the Geesthacht tourism office

By the numbers:
Rated power: 120 MW (less than 3% of Germany’s pumped storage capacity)
Reservoir size: 3.6 million cubic meters capacity, 93 meters elevation, 80 meters head
Discharge: 66 m3/s through three pipes with internal diameter of 3.8 meter
Wind turbine: 500 kW, 1100 MWh/a
Solar PV farm: 60 kW, 573 m2, 50 MWh/a

Written by enviropaul

November 16, 2015 at 3:10 am

How do you recycle a bunker? Part 3: the Wilhelmsburg Flakturm

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The Energiebunker with its solar panels looming over the neighbourhood

The Energiebunker with its solar panels looming over the neighbourhood

What is remarkable about this particular bunker is its setting. A Flak tower nearly as large as the Heiligengeistfeld giant, it had been left to decay in Wilhelmsburg, a suburban neighbourhood that, like the bunker, had itself been left neglected.

Wilhelmsburg is the largest island on the Elbe river. A semi-rural part of Hamburg, it was devastated by a flood in 1962. Wedged between downtown and the industrial harbour, it was considered an undesirable location, a place left for the poor and the immigrant. The presence of polluting industries and Hamburg’s largest landfill didn’t help. Restoring the bunker was no priority.

The Wilhelmsburg bunker a few years ago

The Wilhelmsburg bunker a few years ago

This started to change in the 2000’s. The cheap flats and empty lofts were starting to foster an artistic community (this is where the movie Soul Kitchen was set). Meanwhile, Hamburg was planning for growth in Wilhelmsburg, an initiative labelled the “Leap across the Elbe”. Wilhelmsburg had been identified by the city as the next logical place to expand; the island is near downtown and well served by transit. As with Vancouver, internal immigration to Hamburg is causing a housing shortage as the city is growing. Channeling some of that growth to Wilhelmsburg, then, seemed the next logical step. Except that no right-thinking burger would consider living on the island. Something had to be done.

Enter the 2013 IBA, the international building exhibition. This is a prestigious and uniquely European institution where cities showcase their best new architecture and housing ideas. Hamburg decided that this would be the perfect vehicle to spruce up Wilhelmsburg; and energy efficiency was to be one of the major themes of the exhibition – with a role for the old bunker.

Some of the south face solar PV panels

Some of the south face solar PV panels

From the onset, it was decided that the bunker was to be the focal point of the energy network. After major repairs to ensure structural safety, the bunker was festooned with solar panels. On the south facing side are photovoltaic panels, while the roof holds 1350 m2 of thermal collectors, the largest such roof system in Germany.

At least that’s what you see from the outside. What you don’t see is a panoply of generators: a wood chip boiler, a biogas-fueled cogenerator, and a gas boiler for peak demand. These all work together with the solar panels to provide heat for the district, fifty hectares home to three thousand households. The cogenerator, along with the solar panels, also provides electricity for a thousand households.

But the bunker is cavernous, so aside from the generators and boilers there is room for the showpiece: an enormous (2000 m3) insulated water tank for heat storage. Hot water from the thermal solar collectors is stored there overnight; the heat is released in the early morning when heating demand comes on. As a result, the power output from the boilers need only be about half the size as they would be without heat storage (6.5 MW as opposed to 11 MW without). This means huge savings with respect to the cost of the boilers, but it also means that much less fuel and therefore far fewer greenhouse gases are emitted as a result. The thermal storage also makes it possible to recover heat from the nearby Nordische Oelwerke plant, heat that would otherwise be wasted.

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Looking out from Cafe Vju

As an engineering prof from TUHH told me, “they threw in everything they could think of”; and indeed, the bunker has become a demonstration project for a variety of technologies. This really matters: people are understandably reluctant to invest in unproven technologies, which is why successful demonstration projects are so valuable. (Even so, acceptance is slow in coming in some areas; some the appartment building owners near the heating grid have refused the connection, even though it was shown to them that an annual saving of 40 Euro cents per square meter would be realized, and that the building would become eligible for an energy conservation subsidy. Go figure.)

Be that as it may, the massive building still looms over the neighbourhood, but is now a benevolent, warm, tamed giant. The elevator to the eight floor opens onto Café Vju (pronounced “view”), a pleasant setting with a bare-concrete-chic décor and one of the very best views of the city.

And the neighbourhood? Yes, it is gentrifying; that is unavoidable with projectys like these. But here’s the kicker: housing is, if anything, cheaper. The buildings now heated by the bunker pay less for energy than before. Yet most of these belong to SAGA-GWG, a government company that looks after social housing (social, or subsidized, housing comprises a much larger proportion of the housing stock than in Canada); so, rents are controlled. Not bad!

By the numbers:
Solar PV wall: 670 m2, 0.1 MW, generating 78 MWhr
Solar thermal roof: 1350 m2, 750 kW of hot water
Cogenerator: 510 kW electric, 2700 MWh/a; 600 kW thermal, 3750 MWh/a, using biogas from the wastewater plant
Wood chip boiler: 2 MW thermal, 10,500 MWh/a
Natural gas boiler: 2.15 MW thermal, 3570 MWh/a (used for peak loads only)
Recycled waste heat: 500 kW, 4000 MWh/a
CO2 savings: 6,600 tonnes/a
Production: 22,500 Mwh/a of heat for 3000 homes in a 0.5 km2 area , 3000 MWh/a of electricity for 1000 homes

How do you recycle a bunker, part one, is here, and part two is here.

Written by enviropaul

November 11, 2015 at 9:42 am

The Isebek, or how to bring a canal back to life

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A view of the Isebek canal in Hamburg

A view of the Isebek canal in Hamburg

The Isebek is the most urban of all the canals that flow into Alster Lake in Hamburg. It is also the most polluted – or at least it used to be. How it came back to life is a remarkable story, and one that has lessons for Vancouver.

The Isebek canal, west of Alster lake

The Isebek canal, west of Alster lake

A bit of historical context is needed here. The Isebek river gets its name from a dialect form of Eisen, or iron; this already indicates potential problems. The river was channeled into a canal in the nineteenth century, to facilitate transport, at about the same time as sewers were being built. (This was done after 1842, when the city rebuild after a catastrophic fire that destroyed most of the city.). Before then, waste flowed directly from gutters into the creek, or was dumped from buckets, causing citizens to complain about the stench in summer. The sewers helped, but there was no treatment: both rainwater and wastes were conveyed through these pipes, what we now called combined sewers. But the lack of treatment meant that, even with the smaller population of the 1800s, the creeks and canals were badly impacted; since many had to get their drinking water straight from there, it is no surprise that Hamburg suffered a massive cholera epidemic in 1892.

The city responded – grudgingly, and too late – by providing a network of piped water, and eventually channeling all the sewers into large pipes that deliver sewage to treatment plants along the Elbe. This helped clean up the creeks and canals, and fish came back.

This should have been sufficient for canals like the Isebek, except for one thing: the older sewers are still combined sewers. This means that they overflow during storms, straight into the canals. This is particularly acute along the Isebek, since the area is densely built-up and there are few natural areas that allow rainfall to gently seep into the ground. (A similar issue exists in Vancouver and New Westminster, by the way: sewers in both areas are combined, and overflow into the Fraser or Burrard Inlet at every major storm.) As a result, though fish were now back living in the Isebek, fish kills following storms were frequent until the 1990s.

The Isebek runs through tony Eimsbuttel - right behind these buildings

The Isebek runs through tony Eimsbuttel – right behind these buildings

In the 60’s the city thought that the easiest way to deal with the problem was to make it go away: pave the damn thing. This was narrowly avoided through extensive public protests. So Hamburg – grudgingly, again – launched a series of initiatives, and then got caught at its own game, deciding to get serious and push for the Greenest City Award, which it got in 2011.

First, the city built a series of underground storage basins to collect storm runoff and prevent overflow of the combined sewers into the canals. The storage basin for the Isebek, on Lehmweg, has 7,500 m3 of capacity and helps prevent overflows from six combined sewers outfalls. Curiously, the structure is often used as a meeting point for walking groups.

The sewage reservoir on the Isebek

The sewage reservoir on the Isebek

(This is something that I’d like to see Vancouver do. Yes, these are big, costly projects. But they create jobs, and mostly, they really help, and our salmon could use a hand.)

That alone isn’t quite enough. Combined sewer overflows have been reduced by 70%, which is great. But Hamburg is looking at the writing on the wall: climate change. Worse storms are coming.

So the city has decided to embark on a series of new initiatives. One is the completion of a mega interceptor to channel sewage away from the combined sewers. This is a huge project, and my first inkling of it was a chance meeting with a legal photographer: someone who takes pictures of all the buildings, heritage and otherwise, before work proceeds, so that if someone sues the city for cracks or damages, there is documentation.

Another measure that has been used on the Isebek is aeration. The canal is quite shallow (less than one meter in places) and the water is often stagnant. So the canal would stink in summer, even without overflows. To prevent that, the city installed an aeration tube that runs the length of the canal, diffusing air into the canal water like some giant aquarium. The system, two kilometers worth of pipe with 6000 diffusers, has been in operation since 1990.

Despite the urban setting, the Isebek has some wooded shorelines

Despite the urban setting, the Isebek has some wooded shorelines

But another key initiative is the one called the Green Network. Ostensibly intended to create green spaces, one of the main objectives of the initiative is stormwater management. By increasing surfaces where rain water can infiltrate – green roofs, rain gardens, porous pavings, etc – the city hopes to prevent the worse of local storm flooding. As a result, storm sewers have less water to deal with, and are less likely to overflow.

Does that mean that the water is now fine and safe? By and large, yes, but not completely. A few years ago, a 44 year old man came down with a mysterious illness characterised by a high fever. This was a rare case of leptospirosis, and he most likely contracted the bug while practicing eskimo rolls in his kayak on the Isebek. Leptospirosis is caused by a nasty bacterium carried by mice and rats, and is not a reflection of poor water quality; but still.

I would so love to see my city copy some of these initiatives. Vancouver has embarked on a 100 year-long program of replacing combined sewers with separate sanitary sewers and storm drains. It is hugely costly, and of questionable effectiveness, since storm water itself can be fairly contaminated. (In separate sewers storm waters are not treated.) Instead, how about a few storage basins, a clever system of outflow control, and especially, especially, green infrastructure: rain gardens, green roofs, infiltration basins…it’s not like we lack the space, being built much less densely than Hamburg. Yet, dense as it is, Hamburg is finding a way to go green.

A little pontoon house nestled among the buildings

A little pontoon house nestled among the buildings

Why is that so? I don’t know, but here’s a hint. The environmental group NABU mounted a campaign, a few years ago, against a project approved by the city. This was to be an office complex near the Isebek; NABU said it was in the wrong place, would damage some critical bird and bat habitat, and mostly the paving of the site would send a lot of excess surface runoff to the beleaguered Isebek. Faced with ongoing public opposition, the city relented and withdrew its approval. They listened to their citizens.

I guess they have to: like its federal counterpart, the political system here has been mixed proportional since the end of the war. That means government by coalition, where being attuned to the public is key to staying in power.

Written by enviropaul

November 10, 2015 at 12:19 pm

The Doppel X building

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Doppel X at night, a photo from the rental agency

Architecture geek that I am, I went to take a look at the Doppel X building, a twelve-story office tower completed in 2000. Designed by Hamburg starchitect Hadi Teherani, the building won several prizes and incorporates low-cost construction material with energy saving features, as well as indoor gardens. It owes its name (double x) to its floor plan, which looks from the air like a double cross.

When I went to visit the building was eerily empty. I later found out that its tenant, a large insurance company, pulled out in 1999 as the economic crisis worsened. One of the design flaws of the building, all 17,000 m2 of its floor space, may be that it is meant for occupancy by a single tenant.

The empty building when I visited

The empty building when I visited

But it won’t remain empty much longer. Faced with a critical shortage of of housing, the city has decided to rent the building and convert it into housing for 1100 refugees. In Hamburg, there is a vacancy of nearly one million square meters of office space, and half of this will be conscripted for temporary housing, the city paying market rates for renting the space. How the refugees will adapt to these unusual living quarters remains to be seen, but it has to be better than tents.

I knew none of that when I went to see the building, which intrigued me for several reasons. One is the envelope: this tower looks from a distance as if covered in cling-wrap. This is an external, transparent wall that serves to further insulate the building and act as a sound barrier, while allowing natural light to shine in as well as allowing for natural ventilation. Double X has taken this approach to an extreme, where the outside cladding encloses a rectangular space that includes much of what would normally be considered “outdoors”. Several other buildings also use this approach, notably the nearby Berliner Tor Centre and the Unilever Tower in Hafen City.

Another thing that I noticed is the fact that the energy performance – how much heat and electricity is needed to run the building – is clearly advertised on real estate sites that advertise office space for sale or lease. I later found out that this is a legal requirement.

Indoor gardens are an integral part of the design

Indoor gardens are an integral part of the design

According to its Energieausweis für Nichtwohngebaüde (energy certificate – for non-residential buildings, ironically), heat comes from district energy at a rate of 209.7 kwh/m².a, while the electricity needed is 58.6 kwh/m².a. The audit certificate, valid until 2020 (all buildings must have one), states that the building is operating better than the average building of this type (320 kwh/m².a, if you must know). The certificate looks like the “Enersave” designation we use in Canada for appliances, but with many more details. For instance, specific amounts of energy for ventilation, heating, lighting, and air-conditioning, are all listed. It also states that the CO2 emissions are 83 kg/m².a.

And of course, the degree to which the indoor plants are an integral component of the building is pretty cool. There used to be a indoor pond, as well, but this water feature has been replaced by a glass shard sculpture. The water was causing some humidity issues for the tenant. A design flaw, to be sure, but I love the fact that here, builders are willing to try new approaches.

The other two buildings I mentioned that use this double envelope approach, the Berliner Tor Centre and the Unilever Tower, are both highly performing buildings themselves. But this double envelope is not a must for energy savings; while looking up the Unilever Tower, I stumbled upon an article about the old Unilever Tower, a bland 23 story tower built in the 60s, now known as the Emporio building.

The facade of the Berliner Tor Centre, showing the envelope element

The facade of the Berliner Tor Centre, showing the envelope element

This building was completely renovated –rejuvenated, really – in 2012. The original glass of the transparent façade was removed and replaced by modern, high-efficiency glazing. The building is now as performant as a new design; its CO2 emissions and energy requirements per square meter of floor area are actually better than that of the Doppel X. The Emporio is now rated silver for the German Sustainable Building Council and LEED platinum.

Hmm…LEED platinum, German silver, something tells me that the German criteria are somewhat more demanding. But the key lesson is this: the energy hogs built in the sixties can and should be upgraded to high energy efficiency. But we can also build new, spectacular architecture, and make them supermely efficient. The technology is there to do it all.

Written by enviropaul

November 2, 2015 at 12:43 am