太陽能電池之生命週期評估

Abstract

本研究藉由生命週期評估技術，以生命週期軟體DoItPro，並採用Eco-indicator 95 為環境衝擊評估模式，量化多晶矽與 a-Si 薄膜太陽能電池產品於製造及使用階段所衍生的環境衝擊大小，針對能源、物料、空氣污染物、水污染物及廢棄物進行盤查分析，並計算各階段之環境衝擊，進而比較二種太陽能產品對環境衝擊的差異。 研究結果發現，太陽能電池在製造階段對環境主要衝擊為能源及水資源耗用，製造1kWp a-Si薄膜太陽能電池需要消耗能源7,940 MJ、水資源3,918 Kg；製造1 kWp多晶矽太陽能電池則需消耗能源4,446 MJ、水資源2,226 Kg。 使用階段太陽能電池對環境衝擊為正向，主要以降低能源耗用及削減全球暖化為主。以20年使用壽命計算，1 kWp a-Si薄膜太陽能電池可產生能源3,589,50 MJ、削減20.9 公噸CO2排放；1 kWp多晶矽太陽能電池可產生能源326,408 MJ、削減19 公噸CO2排放。 整個生命週期評估結果顯示，太陽能電池使用階段產生能源遠大於製造階段消耗之能源。從原料開採到產品使用階段，1 kWp a-Si薄膜太陽能電池可產生能源351,010MJ，多晶矽太陽能電池可產生能源321,962 MJ，對於削減能源使用有相當貢獻。

This research which is applied with the life cycle appraisal technology is used the life cycle DoItPro software and Eco-indicator 95 as the environment impact appraisal pattern to quantify the environment impact which grows in the manufacture and the operational phase of the Polycrystalline silicon and a-Si thin film solar cell. To make a questioning analysis on the energy, the material, the air pollutant, the water pollutant, and the waste and calculate the environment impact of various stages, then, compares the environment impact differences of the two kind solar energy products. By the study results we can find that main environment impact on the solar cell manufacture stage are energy and water resources consumption. To produce 1kWp a-Si thin film solar cell need to consume 7,940MJ energy and 3,918 Kg water resources, otherwise, make 1 kWp Polycrystalline silicon solar cell need to consume 4,446 MJ energy and 2,226 Kg water resources. The environment impact of the solar cell operational phase is forward, to reduce energy consumption and the global warming are the major objectives. By the 20 year service life statistics, 1 kWp a-Si thin film solar cell may produce 3,589,49 MJ energy and reduce 20.9 tons CO2 emissions, otherwise, 1 kWp Polycrystalline silicon solar cell may produce 326,408 MJ energy and reduce 19 tons CO2 emissions. The appraisal result of total life cycle showed that the solar cell operational phase energy is higher more than the energy of manufacture stage consumption. From raw material to the product operational phase, 1 kWp a-Si thin film solar cell may produce 351,010 MJ energy and the multi-crystal silicon solar cell may produce 321,962 MJ energy, which are really contribution for energy reduction.