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What is the cost of vertical farming?

Whether vertical farming can contribute to food production also depends on the costs for water, energy and CO2, says Luuk Graamans of Wageningen University & Research.

The Greenhouse Horticulture Business Unit of Wageningen University & Research and TU Delft are investigating the feasibility of vertical farming as a new production system.

Complex

So, how can vertical farming contribute to (inter)national food production? This question is more complex than it initially seems, according to Luuk Graamans. “The answer does not only depend on the production, but also on the costs for water, energy and CO2‘”, he says.

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The combination of high-density crop production and a closed construction necessitates a different approach with respect to heat, cooling and dehumidification when it comes to vertical farming. - Photos: AFP
The combination of high-density crop production and a closed construction necessitates a different approach with respect to heat, cooling and dehumidification when it comes to vertical farming. - Photos: AFP

Greenhouse models

Graamans gives an example: “How much does it cost to produce one head of lettuce? The answer is fairly well known when it comes to cultivation in greenhouses in the Netherlands. Greenhouse models and growth models can be used to predict the production at a certain consumption of water, energy and CO2.”

Also read: Indoor farming technology market to grow to $ 40.25 billion

However, according to the scientist, those models are not suitable cultivation in a vertical farm. “The combination of high-density crop production and a closed construction necessitates a different approach with respect to heat, cooling and dehumidification.”

Energy consumption of a vertical farm

Graamans says the key question when comparing both cultivation systems is: how much energy does a vertical farm need? “The required amount of water and CO2 can be reduced compared to a ‘traditional’ greenhouse, but this is not the case for the cooling and dehumidification demand. The high internal heat load and the lack of natural ventilation ensure a high cooling demand, which consequently results in residual heat.”

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 A worker checks on baby kale grown in vertical grow towers in Newark, New Jersey (United States). Residual energy coming from vertical farms could be exchanged energy with other users in cities.
A worker checks on baby kale grown in vertical grow towers in Newark, New Jersey (United States). Residual energy coming from vertical farms could be exchanged energy with other users in cities.

Re-use residual heat

Graamans says the question is whether this residual heat could be used in the surrounding urban environment. “One of the key features of vertical farming is that it can take place in the city, which would allow it to exchange energy with other users. Those other users could become customers of the residual heat from the vertical farm.”

Feasibilty of vertical farms in 5 steps

WUR and TU Delft have joined forces to calculate the feasibility of vertical farms in 5 steps. The first step investigates how plants process energy in a closed cultivation system. The second step concerns the total energy demand: how much energy does vertical farming need? Step 3 focuses on optimising this energy consumption and step 4 on the integration of the vertical farm into the city.
Ultimately, this information is used in step 5to calculate the financial feasibility of (urban) vertical farming. The research project will be completed by the end of 2019.

Also read: First automated vertical farm almost operational

One comment

  • JG Lodge

    As is so typical this article fails to mention the biggest costs of vertical farming. When talking about growing crops that most growers pay more to deliver than to grow we must take into account that the final mile is always the most expensive. Swapping a few trunk road miles for extortionate city building costs will never make sense. For fresh produce this is due to the amount of transit only packaging we then expect the customer to dispose of responsibly while they already pay to dum CO2 and heat. Then there is the crazy situation of restricting what can be grown by paying to shut out sunlight and paying even more in a vain attempt to recreate it. Those who make claims about sustainablity and using renewable energy fail to acknowledge they need more agricultural land to be covered with Solar PV than they claim to save. The last thing we should be doing is adding unnecessary costs for food those who most need to improve their diets can't afford when there are ways for urban farming can reduce costs.
    Finally there is the need to look beyond what it takes to grow a healthy crop. We humans (just like most animals) need trace elements and nutrients a plant doesn't. Using Electrical Conductivity as a proxy for nutrient levels is not enough. Using too much of the wrong technology is preventing some benefits that can be acheived far more effectively with less effort.

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