Greenhouse Gas Emission Calculation Model of Printed Circuit Board for Power and Industry System (the second report)

Abstract

Power and industry systems include Printed Circuit Board（PCB）and manufacturers are required to conduct Life Cycle Inventory（LCI）analysis in the aspects of GHG and CO₂ emissions. However, it can be difficult to obtain numerical data used for LCI of PCBs due to a large number of parts composing, and thus subjects remain in promoting LCI. To solve those problems, Power and Industry Systems LCA WG of the Japan Electrical Manufacturers’ Association（JEMA）has been working toward calculations of GHG and CO₂ emission factors through development and updating of guidelines and release of the first report which is predecessor of this report. Regarding the GHG and CO₂ emission factors of PCBs derived from the first report, there were still challenges such as the small number of samples and no quantitative classification. Therefore accuracy improvement of emission factors of PCBs was aspired through increasing the number of samples by additions and subdivisions, and analyzing whether numbers of layers affect GHG and CO₂ emissions. As a result, authors could establish a flow chart to derive emission factors of PCBs by applying areal density and number of layers as parameters, and formulas to derive emission factors considering numbers of layers. For PCBs including active elements, GHG emission factors are 100 - 250 g-CO₂eq/g and CO₂ emission factors are 65 - 215 g-CO₂/g, depending on numbers of layers. On the other hand, for PCBs including passive elements, GHG emission factor is 45 g-CO₂eq/g and CO₂ emission factor is 35 g-CO₂/g, not depending on numbers of layers.