Energy-economic-environmental cycle evaluation comparing two polyethylene and polycarbonate plastic greenhouses in cucumber production (from production to packaging and distribution)

Abstract

Excessive consumption and improper management of inputs would lead to environmental damages, as well as decreased economic benefits. Thus, a thorough examination of the entire production process from the viewpoint of energy flow, economic profit, and environmental effects can identify hotspots and facilitate input management. Accordingly, in the current investigation, energy, economic and environmental aspects of greenhouse cucumber production systems were measured by life cycle assessment (LCA) technique and cumulative exergy demand (CExD) analysis by considering different greenhouse structures. Furthermore, the data envelopment analysis (DEA) approach was used to determine the efficiency of manufacturing units and optimal consumption pattern. The information required was acquired through interviews and questionnaires with 35 greenhouse owners, and consultation with greenhouse enterprises in the Khuzestan province of Iran. Based on the findings, energy consumed was 6626.45 MJton^-1 in Sc1, and 6410.32 MJton^-1 in Sc 3. The findings of benchmarking revealed that boosting the efficiency of the crop production process can lower input energy by 14.80%. The energy consumption for the construction of the first and second type of greenhouses was calculated to be 14,811.13 and 17,541.73 MJ (1000 m²)^-1, respectively. With regard to the production variable costs, chemical fertilizers and labor had the largest contributions to the total expenses, at 7.6 (15.41%) and 7.87 $tonne^-1(15.94%), respectively. In the evaluation of the energy and economic indicators, the combined indicator of Energy Intensiveness for the first and second types of greenhouse systems was found to be 80.26 and 77.07 MJ$^-1, respectively, indicating higher energy-economic productivity of the first type of system. Based on LCA results, direct emissions due to input consumption (air: carbon dioxide (CO₂), and nitrogen oxides (NOx); soil: mercury (Hg), copper (Cu), and lead (Pb)), and indirect emissions induced by chemical fertilizers, greenhouse structures, and chemical pesticides production are the environmental hotspots.

Keywords: Cumulative exergy demand; Life cycle assessment; Polyethylene and polycarbonate plastic-greenhouses; Vegetable production systems.