Energy modelling and analysis of vertical farming for vegetable production

Abstract

Vertical farming has gained popularity in the last ten years as a potential solution to produce food using minimal resources. A key challenge in vertical farming is intensive energy usage. Limited research exists however on the energy consumption for vertical farming facilities in cold climate conditions. An energy model was developed to estimate the energy consumption for growing lettuce in a small pilot facility. To validate the model, two tests of butter head lettuce, loose leaf lettuce, and kale were grown in the pilot facility. One test occurred from January – February 2024, and the second was in September – October 2024. During the testing period energy usage for the HVAC (heating, ventilation, and air conditioning) system, lighting, irrigation, and IoT sensor and control were recorded and compared with model estimations. The results showed that the two highest energy usages were from lighting and HVAC. Lighting accounted of 46 %– 75% of the total energy consumption, whereas HVAC accounted for 22% - 52%. Overall, it took approximately 29.6 kWh in the winter and 43.9 kWh in the fall to grow looseleaf lettuce for one crop cycle. It was found that less energy was required to operate the SVF in the winter than in the fall due to not requiring cooling during the winter season. The average energy consumption was 451.8 and 676.1 kWh per month for winter and fall, respectively. The energy consumption per m2 of floor area measured in this study (517.2 - 773 kWh/m2y) was generally lower than that in different geographic regions reported in the literature (850–1150 kWh/m2y). The energy model developed in this study performed well for calculating energy consumption by the lighting system (LEDs) but it was less accurate for calculating heating requirements. Overall, the findings from this study proved that vertical farming could be adapted successfully to cold climate regions.