| Summary: | Four solar cells dominate the Swedish market today and are divided into two groups; first generation and second generation. The first generation involves of two silicone solar cells called mono-and multicrystalline solar cells. These solar cells were, as the name indicates, first on the market and today receive the highest efficiency. Due to high manufacturing costs, the second generation was developed which became thin film solar cells. The two most common solar cells in that generation are CdTe and CIGS, which account for about 20 percent of the solar cell market today while the first-generation accounts for the remaining 80 percent. Going towards a sustainable future it’s important and clear that both companies, cities and countries are ready meet the challenges. The solar cell technology has gained high confidence to bring in sustainable electricity production. Investors in Sweden experience the lack of a valuation concept from an environmental perspective between the solar cells on the Swedish market. The study has examined how the four different solar cells affect different environmental categories and which materials in the solar cells that are the most critical. By simulating the electricity production for a year with Gothenburg's solar radiation, the amount of electricity that could be used or sent to the grid was obtained. Where the silicon solar cells that have the highest efficiency also received the most electricity per square meter of solar cell. After producing electricity production and electricity consumption, the energy repayment period was calculated. Through LCA, 11 different environmental categories were developed to analyze different areas that are affected by solar cell production. Aquatic ecotoxicity of the marine environment was the environmental category that was most affected by the production for all four solar cell types. From the environmental category Global Warming, the amount of carbon dioxide equivalents was studied and then a payback time was calculated. Solar cells generally have three different phases; manufacture, operating and waste. The use phase is considered to be almost emission-free, the waste phase is relatively new for solar cell technologies. This is because no large waste streams have come than when the first major investments took place only in the nineties. The solar cells need different techniques depending on the type. The strategies should be different as different parts should be recycled and reused as far as possible. Due to the fact that there is unstable waste management, this phase has not been studied but only the manufacturing phase. A square metered solar cell was analyzed. For photovoltaic production in Europe, multicrystalline solar cell panels pay back the carbon dioxide equivalents after 11.5 years, while monocrystalline solar cell panels pay again after 14.3 years, ie after about half the life. CdTe paid the carbon dioxide equivalents fastest, after 2.2 years, and CIGS after 3.6 years. This means that the thin-film solar cells have the fastest time to get minus emissions. It is not justified to invest in solar cells manufactured in China when operating in Gothenburg, only after studying solar cell production. When the repayment period for carbon dioxide equivalents has been calculated, a Nordic electricity mix has been calculated with, depending on which electricity mix is chosen, it either gives reasons to not invest or to invest in solar cells. It is therefore important to be clear about what use the solar cells will have and which electricity is actually replaced before investors decide whether solar cells are the right energy source to invest in.
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