Energy cost impact analysis on the total cost of the crop production for different operating conditions. A salad production case study

Nowadays, with the constant global population growth, urbanization, pests use, climate change and resource degradation, the water-energy-food link is constantly stretched. In order to achieve water and food security, sustainable agriculture and energy production, the efforts of the next few years will be aimed to correctly balance these aspects. Therefore, it will be necessary both to improve the energy performance of traditional systems in the agricultural sector and at the same time to develop alternative and innovative ones. In this context, data from a local farm producing salad have been processed in order to relate the energy consumption of each processing phase to the produced kilogram of crop. In particular, thermal loads are attributed to the corresponding primary energy consumption. A thermo-economic analysis was carried out by considering different scenarios in terms of external ambient temperature and specific cost of electricity. Results show that the thermal load exchanged with the external ambient through the walls and the roof of the plant is about the ʹͲΨ of the outgoing thermal load of the evaporator during the lighting hours whereas the thermal load of the auxiliaries (including the production lines) is about its ͺͲΨ. Moreover, the variation of both the fourth range production lines operating time and the external daily temperature causes a variation in the total energy consumption related to the kilogram of processed product – up to 128%. Finally, several economic scenarios have been implemented in order to take into account the variation of the specific cost of electricity