There are some strange excesses in the need for more sustainability, and especially with regard to the undefined “greening” of things. One of these, and you notice it more and more, is the tendency to plant trees on buildings. Not on the roof, as you might expect, but especially around the facades, especially on balconies. One of the first remarkable buildings was Bosco Verticale in Milan. And sell it as good for the environment, the climate, or for the city quality. Well, a tree on the 20th floor does not contribute to the quality of life on the street. In any case, a building higher than 5 floors does not contribute to the livability of the city, as I argues before. [1] Let alone trees on the 20th floor. In fact buildings normally look like that after having been abandoned for 20 years or so…
What is going on here, are you wondering? I remember a presentation of a building with a lot of “ green, by Kenzo Tange, and at the end of that lecture I asked him how heavy the building was, because of all that green. He promised to send me figures, but he never did.
What actually is created are trees on concrete foundations. Which in all likelihood does increase the environmental impact of the building, but contributes little to the environmental improvements of the city. Moreover, I can already imagine in case of a storm, all those residents standing on their balcony to hold the trees. Although safety measures will have been provided I hope, since a tree sailing down from 20 floors high will give a nice blow in the street. They will probably be secured with cables, introducing a lot of steel.
Alternatively a park with trees could have been created on the same spot, which would probably have been much more effective, for green and livability.. But that does not, of course, yield any money, for the city or project developer, so together decided to do both: develop the project and the park, only now vertically. That no citizen can profit from it, has been overlooked… And this then is picked up by all architectural magazines. Well done, building sector ….
The ultimate solution takes things eve one step further: We also throw people out of the tower, and give it all the way back to nature: to grow plants inside: The vertical farm. It is already happening, since with modern LEDs you can divide light into separate colors as well, and every plant thrives best with its own specific wavelengths. And if something can be done, you have to do it, right? Of course it has to be realized inside a building, you cant imagine direct sunlight entering, that would destroy the entire growth schedule! Very annoying. So there will be a floor with green light, one for red light and so on. This way we ‘effectively’ grow our vegetables. Huh? Effective? By building a tower for it? And then catch the sun with solar panels, make electricity, separate the light frequencies , install LEDs again to bring those frequencies on a plant, and all that in a mega concrete tower …. That’s putting the horse behind the carriage . In a near future we will be standing sweating outside in a barren plain , and begging at the foot of a tower for an efficiently grown food package.
Long live progress.
Starting from solar panels for electricity and light, since we want to convert the entire energy supply into renewable energy, its not going to work energetically: as already mentioned by Caplow. He developed a rule of thumb: you need about 20 times larger surface area for solar panels for serving the artificially illuminated area. If at all you want to work vertically, it can only be effective with direct light. [1]
So vertical farming is nonsense, although someone like Dickson Despommier, with his book ‘vertical farming’, wants us to believe differently. [2] It is mainly the book of a simple dreamer. Let me cite a review of the book in Treehugger:
“ There is much loose talk in the vertical-gardening world about using renewable energy sources to power their grow-lights. That discussion spirals into some interesting circular logic: that we would use solar arrays and wind farms to convert sunlight’s energy into electric current that would feed lamps that would convert a portion of the electrical energy into artificial sunlight to shine on plants so they can convert that light energy into food. At each of those conversion points, there are big losses of energy and heavy infrastructure costs. It’s about as wasteful as a system can be. Better to let crop plants do what they do best: capture cost-free, emissions-free sunlight for themselves, directly.” [3]
And that same author shows a research from Japan, which calculates around 1200kWh input need, in electricity to grow 1 kg product in dry matter. [4]
The overall conclusion: Whatever artificial energy source you use to grow your plants in a tower, what you actually do is give a boost to climate warming. In other words, it is another great example of creating a hype, with technology push as the soap bubble.
Almost everyone in this getting involved in this debate incidentally ignores the impact of the building itself. With materials in the first place. A huge amount of impact is created in building such a tower. : both by depleting materials as well as in fossil energy to extract and process these materials into ready-to-use products. Which is, by the way, ignored in virtually the entire energy transition story, or at least ‘forgotten’.
In the second place there is the impact of the height of the building. Because what does a high-rise actually do? That steals the potential solar energy from the neighbors. Since the tower casts a shadow far beyond its own building boundaries, And if the tower itself , in the best case, already generates energy with solar panels on the facades, then that energy is stolen solar energy from the neighbors, because they are shadowed and receive less sunlight on their panels. And that is 1 to 1. Not directly visible of course, because the earth rotates and the panels of one neighboring house are only temporarily shaded, but then those of its neighbors and so on. Cumulatively its as much as the tower intercepts. From solar energy point of view, you can have it only once. If you want to deal with this in a decent way , a building will also have to include the shaded ground in its building plan. Which might on average be as long as the building is high. ( on our longitude)
But above all, if you are going to work with artificial light, why should it be in a tower to be built? Its possible just as well underground, in fro instance a abandoned mine, or in excavated tunnels such as in the Netherlands the former limestone quarries, a old tunnel system in a local mountain for example. . These quarries at first have delivered building material, and can now serve as ‘buildings’ for vegetable cultivation.
In short, all that green, all those towers, all that vertical farming. Nonsense. Its Vertical Framing. Just stay with two legs on the ground ….
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[1] Bosco Verticale: https://inhabitat.com/bosco-verticale-the-worlds-first-vertical-forest-nears-completion-in-milan-new-photos/
[2] article on “dead end roads” : http://www.ronaldrovers.com/the-elevator-a-dead-end-road/
[3] https://www.economist.com/node/%2017647627
[4] Despommier: the vertical farm http://www.verticalfarm.com/
[5] https://www.treehugger.com/green-architecture/vertical-farms-wrong-so-many-levels.html
[6] https://www.alternet.org/food/why-growing-vegetables-high-rises-wrong-so-many-levels
[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3881955/
[7] Conference paper 3D exergy approach : https://www.researchgate.net/publication/271269702_URBAN_AND_BUILDING_DYNAMICS_A_3D_EXERGY_APPROACH_REQUIRED
