Miljökrav på solceller : En utredning om koldioxidutsläpp från kristallina kiselsolceller

Sammanfattning: This master thesis is an investigation of environmental sustainability of photovoltaic (PV) modules. The purpose is to examine how purchasers of PV systems could put requirements on the modules so that their life-cycle carbon dioxide emissions reduces in the most effective way. The purpose is also to survey environmental third-party certifications for solar modules. Only mono- and multicrystalline silicon modules are considered. In the first part of the thesis, the carbon dioxide emissions from the manufacturing and transportation of different modules are calculated. Furthermore, the solar electricity production is simulated in the software PV syst. Modules with different peak power capacity, origins and manufactured with different techniques are compared. In part two, recycling techniques and regulations for management of end-of-life-modules are investigated. The number of end-of-life modules based on Solkompaniet Sverige AB´s historical installations are estimated and out of these, their potential economic value, based on two different recycling scenarios, is calculated. According to the results, monocrystalline modules cause higher emissions than equivalent multi-crystalline from the same manufacturer. Modules with the same peak power and silicon but with different origins and silicon manufactured with different technologies, produce about the same amount of electricity, but show a large variation in carbon dioxide emissions, mainly due the electricity consumption and the characteristics of the electrical mix used in the manufacturing process. The modules’ operating time in addition to pre requisite conditions for mounting are crucial for thee missions per produced kWh electricity, contrary the transports have very little effect on the total emissions. Carbon dioxide emissions could be reduced through re-usage of elements from recycled end-of lifemodules, particularly aluminum and silicon, but economic factors hinder this today, mainly due to too few end-of-life modules. Silveris the most expensive element in a module. The value of end-of-lifemodules will decrease by decreasing silver content, but overall increase due to increased waste volumes. The future economic value of end-of-life modules is hard to estimate, but could be crucial for the possibility to take advantage of the environmental benefit from treatment of end-of-life modules. In order to reduce carbon dioxide emissions from solar modules, requirements should be directed towards the module manufacturing process. This thesis emphasizes pre requisites expected to give lower emissions, hence modules that are more likely to cause lower environmental impact than others. To be able to develop specific requirements, more transparent and reliable energy consumption data is necessary. It exists very few, and no Swedish environmental certifications specifically designed for solar modules. The ranking list Solar Scorecard is not a certification but seems to be the most used in order to demonstrate manufacturers' environmental performances.