ENVIRONMENTAL LOAD REDUCTION EFFECT BY RECYCLING USED PHOTOVOLTAIC GENERATION PANEL GLASS

Abstract

 The demands of photovoltaic generation (PV) are increasing as the public eco-awareness grows, but there is concern of enormous volume disposal of PV panels in the near future. It is calculated by Ministry of the Environment that if the PV panels life expectancy were 25 years, its final disposal amount reaches 800,000 ton in 2040. And its disposal amount is equivalent to 6% of the present final disposal amount of whole Japan. Considering the load to future's final disposal site, its influence can't be ignored any more.
 For this reason, some companies are already working to develop the recycling method of PV panels in Japan. However, details of its reductive effect of environmental load is not so certain. So the purpose of this study is to uncover the reduction in CO2 emissions by the recycling of PV panel's glasses (main constituent materials of PV panels are glasses which accounts for more than 50 % by the weight ratio.) through the inventory analysis.
 At first, we carried out hearing survey on PV panels disposal service vendors, recycled products manufacturers and so on, in order to grasp component materials of PV panels (5 kinds of PV panels were targeted in this research), manufacturing process of recycled products, specification of prosessing apparatus, etc.
 Then we set two flow charts based on hearing survey. First are proposal procedures that are processes of PV panel's glasses recycling to ceramic tiles, paving blocks, and sound proof panels. Second is currently procedure as a comparison that is process of PV panels recycling to roadbed materials (we also considered that currently procedure is landfill disposing without PV panel's glass recycling). We calculated respective procedure's CO2 emissions per PV panel ton treatment by the inventory analysis.
 The followings are the main findings of this study:
 ·Each of PV panels are composed of different materials ratio, so there are difference of reduction in CO2 emissions between respective PV panels.
 ·At the time of recycling to ceramic tiles, it was confirmed that the fuel consumption in the baking process can be reduced 33 % by using glass, not a natural raw material like a feldspar. Therefore, the substantial CO2 reduction effect was suggested.
 ·Recycling to ceramic tiles, paving blocks and sound proof panels using glass of PV panels gave more than 10 % CO2 reduction ratio, even when any PV panels were subjected. It was the case when CIGS PV panels are recycled to sound proof panel that the CO2 reduction ratio becomes biggest, and its CO2 reduction ratio was 61%.
 ·We showed that which productization or occasion of PV panel kinds are able to get the amount of CO2 reduction beyond 140kg-CO2. It was the case when CIGS PV panels are recycled to ceramic tiles that the amount of CO2 reduction becomes biggest, and its amount of CO2 reduction was 441.6kg-CO2.
 ·Amount of CO2 reduction didn't become substantial minus effects in the comparison even when the currently procedure is landfill disposing. Combined with the volume reduction of final waste, it is suggested that PV panel recycling reads to significant reduction of environmental load.