Protein plant factories: production and resource use efficiency of soybean proteins in vertical farming

Samenvatting

Background
Controlled environment agriculture (CEA), particularly vertical farms (VF), also called plant factories, is often claimed as a solution for global food security due to its ability to produce crops unaffected by weather or pests. In principle, essential macronutrients of the human diet, like protein, could technically be produced in VF. This aspect becomes relevant in the era of protein transition, marked by an increasing consumer interest in plant-based protein and environmental challenges faced by conventional farming. However, the real question is: what does the cultivation of protein crops in VF imply in terms of resource use? To address this, a study was conducted using a VF experiment focusing on two soybean cultivars.
Results
With a variable plant density to optimize area use, and thanks to the ability to have more crop cycles per year, protein yield per square meter crop was about 8 times higher than in the open field. Assuming soy as the only protein source in the diet, the resources needed to get total yearly protein requirement of a reference adult would be 20 m2 of crop area, 2.4 m3 of water, and 16 MWh of electricity, versus 164 m2, 111 m3 and 0.009 MWh in the field.
Conclusions
The study's results inform the debate on protein production and the efficiency of VF compared to conventional methods. With current electricity prices, it is unlikely to justify production of simple protein crops in VF or promote it as a solution to meet global protein needs.