Life cycle assessment of light-emitting diode downlight luminaire—a case study

PURPOSE: Light-emitting diode (LED) technology is increasingly being used for general lighting. Thus, it is timely to study the environmental impacts of LED products. No life cycle assessments (LCA) of recessed LED downlight luminaires exist in the literature, and only a few assessments of any type of LED light source (component, lamp and luminaire) are available. METHODS: The LCA of a recessed LED downlight luminaire was conducted by using the data from the luminaire manufacturer, laboratory measurements, industry experts and literature. The assessment was conducted using SimaPro LCA software. EcoInvent and European Reference Life Cycle Database were used as the databases. The LCA included a range of environmental impacts in order to obtain a broad overview. The functional unit of the LCA was one luminaire used for 50,000 h. In addition, the sensitivity of the environmental impacts to the life was studied by assessing the LED downlight luminaire of 36,000 h and 15,000 h useful life and to the used energy sources by calculating the environmental impacts using two average energy mixes: French and European. RESULTS AND DISCUSSION: The environmental impacts of the LED luminaire were mostly dominated by the energy consumption of the use. However, manufacturing caused approximately 23 % of the environmental impacts, on average. The environmental impacts of manufacturing were mainly due to the driver, LED array and aluminium parts. The installation, transport and end of life had nearly no effect on the total life cycle impacts, except for the end of life in hazardous waste. The life cycle environmental impacts were found to be sensitive to the life of the luminaire. The change from the French to the European average energy mix in use resulted to an even clearer dominance of the use stage. CONCLUSIONS: The case study showed that the environmental impacts of the LED downlight luminaire were dominated by the use-stage energy consumption, especially in the case of the European energy mix in use. Luminous efficacy is, thus, a relatively appropriate environmental indicator of the luminaire. As LED technology possesses generally higher luminous efficacy compared to conventional ones, the LED luminaire is considered to represent an environmentally friendly lighting technology. However, data gaps exist in the data in LED product manufacturing and its environmental impacts. The environmental impacts of different LED products need to be analysed in order to be able to prec