Three years ago I thought the Plantagon vertical farm in a dome was pretty much vaporware, that a dome made little sense, and I was, like many others, tired of all of these architectural fantasies. Since then, some small test facilities have actually been built, and some serious academic work has been done to give the concept some substance. Now, they are actually breaking ground on one, using a very silly three handled shovel that is an interesting analogy to the vertical farm: yes, you can make one, but why would you, and does it work any better than the traditional technology?
The press release says that the project will be
A new type of greenhouse for vertical farming; an international Centre of Excellence for Urban Agriculture; a demo-plant for Swedish clean-tech and a climate-smart way to use excess heating and CO2 from industries. The potential is tremendous and ambitions high for the new greenhouse being built in Linkoping, Sweden, near the regional energy company, Tekniska Verken.
The new website gives some greater detail about how the Plantagon system works, and gives some jazzy renderings of an alternative to the dome. The key is still the a helix system:
The basic idea is to grow vegetables in pots. The pots are then put into trays, which are transported around the growing helix where the cultivation takes place. The trays are equipped with a light sealed nutrient solution reservoir, and the pots are irrigated about three times per day using an ebb-and-flow technique. A capillary mat at the bottom of each tray protects the individual plants from drought. Excess nutrient solution is collected and reused after disinfestation.
They are not kidding around when they say they can scale the thing, proposing this "Plantascraper."
They are indeed pretty vertical farms, in various designs:
The different system designs basically all have the same production flow and location of equipment. The machinery is located in the basement on one or two floors and the trays are transported to the top of the helix by a special tray elevator. The crops grow during the slow transport down the helix and are ready for harvesting when they reach the end of the helix at the basement level. Food is harvested in batches using an automatic harvesting machine. After harvest, the trays and pots are disinfected, and the pots are separated and replanted with another seed for the next round in the cultivation loop. After germination, the pots are recombined with the trays and elevated to the top of the growing helix to repeat the process.
That is totally clear.
Like Gordon Graff's proposal, the Plantagon appears to use plant residues and local manure in an anaerobic digester to generate biogas, to run boilers and chillers for heating and dehumidification. They are building their demonstration plant next to a generating plant to use its excess heat as well.
Is this all more sensible than a three handled shovel? Or is it, as Adam Stein called it, Pie in the Sky? We shall see. More at Plantagon.