T5 or T8 fluorescent lamps : making decision with their carbon footprints

Abstract

The environmental impact especially on climate change through the life cycle of fluorescent lamps (FL) was studied in this research. Products of interest are 36WT8, 18WT8, 28WT5 and 14WT5 FL. The different products were compared based on the same illuminating function, i.e. with the same brightness of 143,000 lumen for 36WT8 and 28WT5, and 26,250 lumens for 18WT8 and 14WT5. Majority of greenhouse gases (GHG) emission occurs during the usage stage due to the electricity consumption of FL. The overall GHG emission throughout the life cycle of each FL could be summarized as follows: 36WT8 emitted 21.9 tonCO₂e, 28WT5 16.7 tonCO₂e, 18WT8 5.1 tonCO₂e, and 14WT5 3.3 tonCO₂e. This reveals that T8 FLs released more GHG than T5 FLs as T8 consumed more electricity than T5. On the other hand, when considering only from raw material acquisition stage to manufacturing process of each FL, the results were: 36WT8 emitted 61 kgCO₂e, 28WT5 73 kgCO₂e, 18WT8 17 kgCO₂e, and 14WT5 26 kgCO₂e, which indicated that T5 emitted GHG more than T8. This was because the small size T5 FL inherited a more complicating and more energy consuming processes when compared to T8. However, the replacements of T8 with T5 according to the energy saving policy of Thai’s government necessitated the assessment of the ballast which is the other main component of the FL set and needed to be used together with the lamp. GHG emission through life cycle of 36WT8 with magnetic ballast equaled to 28.1 tonCO₂e meanwhile 28WT5 with electronic ballast was 18.9 tonCO₂e. This result demonstrates that the change of T8 FL into T5 FL can help reduce the amount of GHG emission up to 9.2 tonCO₂e. Therefore this policy could actually decrease the GHG emission per one lamp set. However, this analysis does not try to incorporate other impact categories and economics into the consideration which could have other implications.