Energy and cost analysis for a crop production in a vertical farm

Nowadays, the agricultural sector is undermined by arable land and water availability. Vertical farms represent an interesting solution offering the possibility to overcome these issues also reducing pesticides use. However, their high energy demands make it crucial to develop an effective methodology to attribute the specific energy cost to the kilogram of each product harvested. A multi-level model considering the elements that intervene in the energy balance characterizing the cultivation phase in vertical farms is introduced below. A parametric analysis is carried out with it, considering different cities and multiple scenarios in terms of lighting efficiency and intensity, leaf surface temperature, electricity and natural gas cost. The results unveil a strong dependence of the total energy consumption and the specific cost of the product on external conditions, such as the climate, the efficiency of the electric national system and the energy cost. Notably, in Riyadh, the energy consumption (10.1 GWh year-1) is up to 86% higher than in Stockholm and 38% higher than in Naples. By means of the internal conditions’ optimization, the specific cost for energy of the lettuce production in the vertical farm growth chamber, is 0.85 € kg−1 in Stockholm, 1.35 € kg−1 in Naples and 1.75 € kg−1 in Riyadh.