リサイクル技術を考慮した太陽電池ライフサイクル評価

抄録

Objective. Recycling of photovoltaic cell will become more important in the near future because of rapid growth of PV installation since the 1990s. It is needed to evaluate the effect of PV recycling from the economical and environmental points of view. In this paper, input energy, CO₂ emissions and capital costs for the production of photovoltaic modules with recycling process are evaluated using a life cycle analysis method. Furthermore, annual production and installed cost for PV modules are estimated until 2050 when PV recycling plants is installed.
Results and Discussion. The lifecycle input energy of the recycling PV module decreases 20% and 71% for the thermal decomposition and the nitric acid treatment, respectively, comparing with the unrecycling one. The CO₂ emission and the cost are also decreased by the introduction of recycling processes. The cost of the nitric acid treatment is low, and the PV module cost decreases 41%. The result of estimation of the annual production and the installed cost for PV modules with the nitric acid treatment shows reasonable cost on 2017 or later.
Conclusions. It was supposed to be difficult to recycle by the thermal decomposition because of cost for the process. Based on the results of the evaluations performed in this study, however, the nitric acid treatment is desirable for PV module recycling. The nitric acid treatment can be expected as a main process of future solar cell recycling due to the lower input energy, the CO₂ emission, and the system cost. PV module recycling is anticipated a practical application in the near future.