Life cycle assessment and economic aspects of laterally integrated solar cell.

Abstract

Sustainable development requires use of many different methods and tools to measure performance with regards to environmental impact. Environmental impact counts for both the emission from the system and also the emission during the manufacturing of the system. The standards for solar cells are given in the ISO 14000 series. ISO standards can only be used for solar systems that are in service. This paper will try to analyze a system which is in its design phase by combining the ISO 14000 series with a quantitative approach from simplification of process-LCA. At the same time it will also try to compute the economics behind the new design to generate a sustainable design. This study is done to analyze the design phase only and to identify any possibility of improvement. This paper also tries to identify the effect of solar insolation on the output of the solar cell. The design that will be analyzed is called a laterally integrated solar cell. In this design, the semiconductors are laterally assembled. Laterally integrated photovoltaic cell design technology is intended as a substitute for a traditional photovoltaic cell offering higher efficiency, lower cost, minimal maintenance and most importantly sustainability. This paper considers energy flows from cradle to gate starting from silica extraction to the final panel assembly. The after use or recycle phase is not considered because this study is intended to understand the design phase and its environmental impacts. The different semiconductors used for this technology include Indium Gallium Nitride (InGaN), Polycrystalline-Si, Amorphous-Si, and Cadmium Telluride (CdTe). The most critical phase is the transformation of extracted raw material into a 99.999% pure form to be used in the production of solar cells. Maximum power point (Pm) and Energy Payback Time (EPBT) have been evaluated, considering different geographic locations with the use of relevant real time values of solar radiation, latitude, longitude and elevations. Evaluation of an existing solar panel system located at UMD as compared to a laterally integrated PV solar panel is also performed. It was concluded from the study that the energy payback time of the system is comparatively higher than other systems present in the market. Solar insolation also plays a big role in the output of the solar system. The difference between the maximum and minimum EPBT of laterally integrated systems at different locations across the globe was about 7.4years. Levelized cost of energy of the system is around $247/MWh. It is very high compared to other conventional and non-conventional energy sources. The factor that supports the design is the present worth of electric power the system will generate over its entire life of 30 years. System results were promising when compared with the University of Minnesota-Duluth solar panel. A laterally integrated system, if substituted for the panel at UMD, will generate 19438.53kWh of electricity and save 12370.68 kg of CO2, 48.60 kg of NO2, and 69.98 kg of SO2 within 18 months of its service.