|Authors: ||T. Shiina, D. Hosokawa, P. Roy, N. Nakamura , M. Thammawong, T. Orikasa|
|Keywords: ||artificial light, carbon dioxide (CO2) emission, electricity, impact assessment, lettuce, life cycle assessment (LCA), spinach|
Life cycle assessment (LCA) is a tool that can be used to evaluate the environ-mental load of a product, process, or activity throughout its life cycle.
Such assessment comprises four steps: (1) goal definition and scoping, (2) life cycle inventory analysis (LCI), (3) impact assessment, and (4) interpretation.
Protected cultivation is a promising production system for stable supply of vegetables.
On the other hand, environment control, e.g., temperature and light, inside the greenhouse requires the use of energy and it results the environmental load.
In this study, a LCI was conducted to evaluate the carbon dioxide (CO2) emission from two different types of plant factories, where leafy vegetables were grown.
Depending upon the degree of the growth environmental control, one is called a perfect control type, and the other is called a hybrid type meaning the sunlight is used in addition to the use of artificial illuminants in the facility.
The functional unit (FU) was set as the amount of CO2 emission per kg of vegetable.
In a perfect controlled facility, the amount of 6.4 kg of CO2 was emitted per kg of leaf lettuce production, and 2.3 kg of CO2 was emitted by spinach production in the hybrid type plant factory.
The amount of CO2 emission from lighting and air-conditioning tended to be large in both plant factories. 90 and 70% of CO2 were emitted from the use of artificial light and air-conditioning system in the perfectly controlled factory and the hybrid factory, respectively.
The result suggested that consumption of electric power was highly responsible for the amount of CO2 emission in the plant factories.
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