Life Cycle Assessment Of Crystalline Silicon Modules In China

Solar energy uesd as a new clean energy has been widespreadly concerned by governments all over the world. LCA is a method for analyzing the environmental impact of a produc system, and a potential method to find the vital parts that mostly affect the environment and to minimize the impacts. There has been plenty of LCAs on PV in China and around the world, however, these studies have serious shortcomings: 1. The lack of complete LCA study of Chinese solar panels----- most of the existing researched are lack of data selecting dessertation and end-of-life discussion; 2. Most LCA studies lack reliability and uncertainty analysis, so as not to make the reader judge the credibility of the results; 3 LCA lack a frame of discussing the uncertainty and improving the reliability. This paper will solve the problems above.Firstly, a complete LCA of photovoltaic panels in China had been established, which mainly focusing on identifying input and output data of unit processes and inventory calculations, besides end of life had been researched: 1. Analysis of data sources and quality(including information about time representation, technical representative, etc.), functional unit, LCI method and principle of distribution, data moduling method and data representation, integrity, reliability, and checking information; 2. Determined input and output data of unit processes, comparative analysis to select the appropriate upstream inventory database, and developed a tool based on EXCEL to calculate life cycle inventory under various stages such as production stage, waste disposal stage, and full life-cycle stages as well as "From cradle to gate" of inventory; 3. life-cycle impact assessment had been completed, under various stages of the production process of solar panels, which highlighted the impact of various input material on the environment, the results showed that the largest impact were the "human health"; as for input materials, "energy" was the most serious cause; 4. A complete LCA interpretation, including the major problem identification, sensitivity analysis, uncertainty analysis, completeness checks and consistency checks.Next, the reliability and uncertainty analysis had been made according to the results of LCA. The results of the sensitivity analysis showed that silver, POCl3 and silicon carbide has the highest sensitivity coefficient SC to the greenhouse effect, " NaOH in second process", "Energy in second process" and "Energy in third process" had the highest sensitivity ratio SR to greenhouse effect. In addition, comparative analysis of acidic and greenhouse models with different time spans had been discussed, basically resulting the same sensitivity outcomes. Uncertainty results showed that in the case of a confidence level of 97.5%, the average standard deviation was 0.19-0.22, only the "acidified" distribution consistent with the same input material lognormal distribution, and for the three different time spans the "greenhouse effect" was most consistent with the maximum distribution. Silicon carbide, polyethylene glycol, aluminum frame and copper had the highest degree of influence over LCA uncertainty.In the end, this paper put the uncertainty to each LCA process and come up with a new framework which would help the further development of LCA studies.Finally, summary and future prospects had been concluded.