It is not possible to produce energy completely free from environmental effects. Solar cells do not cause any emissions and therefore have a very good environmental balance compared to other types of energy. However, in the manufacture and disposal of modules, solar energy also consumes resources and generates waste.
Solar cells take about a year to produce enough energy to produce them. Even under unfavorable conditions, it is no more than two years. A photovoltaic system can produce electricity for decades. The manufacturers give a guarantee for 25 to 30 years. In practice, the modules usually last longer.
One kilowatt hour of solar power causes a greenhouse effect that corresponds to around 40 grams of carbon dioxide. On the other hand, one kilowatt hour of lignite electricity causes 1000 grams of CO2 from the fuel alone. This does not even include the construction and demolition of the power plant. According to a current study, one kilowatt hour of photovoltaic electricity causes only 20 grams of CO2. The reason for this In the past decade, the manufacturing process of solar cells has been greatly improved. The silicon layer in the cells is less than half as thick as before, and there is less waste when sawing the silicon. Frameless glass-glass modules have the best energy balance. Because they do not require an aluminum frame and last longer, they save another 22 to 27 percent in CO2 emissions compared to conventional glass-foil modules.
Photovoltaic modules do not contain any raw materials that are scarce or difficult to obtain worldwide. The most dominant substances in terms of quantity are silicon and aluminum extracted from sand. There is also a small amount of silver in solar cells.
Solar cells are non-toxic and not hazardous waste. However, like other electronic devices, they contain substances that should not be released into the environment. The main concern here is a small proportion of lead, which is installed in electrical contacts. Some solar cells also contain traces of cadmium. During operation, these substances are firmly bound and are not washed out; however, it is important that they are disposed of properly.
