## 4 Results and Discussion
### PV Panels LCA
\begin{tabular}{c c c c} \hline \hline
**Source** & **Functional Unit** & **System’s Boundaries** & **Life Cycle Impact Assessment** & **Results** \\  & & & Method, Software & **CWP** (100 years) 67984 kg CO\_ep+s \\  & & & OOP 5.50 kg 181.5C+s \\  & & From the collection, transportation (600 km) and recycling of F/V water (thermal & Human Toxic (Cancer) 270.7C TiA) & \\  & & & Human Toxic (Cancer) 270.7C TiA & \\  & & & Human Toxic (Cancer) 39.50 C TiA & \\  & & treatment of the F/V modules and the & Human Toxic (Cancer) 39.50 C TiA & \\  & & & & \\  & & partial removal of & Particle Matter 39.50 kg 182.5-q \\  & & the organic F/VA in a noble gas & & Ionizing Radiation 2.86 kg 125.9M/voc-eq. \\  & & environment to final production of the & & Productional zone formation 1.53 kg 2000-eq. \\  & & & Architecting 50.85 m m/s & \\  & & & & \\  & & recovered St & & \\  & & & & \\ \hline \hline \end{tabular} 
\begin{tabular}{c} The thermal treatment of the \\ decompositional [FOOTNOTE:]Footnote : footnotetext: The changes in the \(\Delta\)-\(\Delta\)-\(\Delta\)-\(\Delta\)-\(\Delta\)-\(\Delta\)-\(\Delta\)-\(\Delta\)-\(\Delta\Delta\)-\(\Delta\Delta\)-\(\Delta\Delta\)-\(\Delta\Delta\)-\(\Delta\Delta\)-\(\Delta\Delta\Delta\)-\(\Delta\Delta\  
For the case of c-Si PV modules, the weighted average of multi- and monocrystalline Si PV modules was considered. It was estimated that the used modules would be transported by truck over a total distance of 500 km. The technology of recycling is mechanical. The desirable outputs of the recycling process are the bulk materials of glass cullets, aluminum scraps, and copper scraps. For the case of CdTe PV modules, the average transport distance from the place of installation to the recycling plant was considered as 678 km (data of First Solar's recycling facility located in Germany). The recycling process includes shredding and milling the used CdTe PV modules in the first step, then removing and dissolving the semiconductor film as the second step. The LCIA results for both types of panels are presented in Table 2. As one can see, CdTe PV modules are superior in environmental performance to c-Si PV modules in all categories of environmental impact. This conclusion can also be used in the eco-design of energy systems. Note that even though both LCAs of [41; 67] were performed throughout the entire life cycle, they still do not provide a complete picture of all the adverse effects of a PV plant. They do not take into account the productivity of a PV plant at the operation stage. More efficient PV plants (both by capacity factor and by energy conversion coefficient) can produce more useful products (electricity) for their life cycle and thereby reduce the need for the production and installation of additional PV capacity. Therefore, it is more appropriate to use 1 kWh of generated electricity as a functional unit for the LCAs of all energy facilities, including solar panels. Recalculation of the results of these two studies into other functional units (1 kWh of electricity), unfortunately, is impossible, since the location of the installation of solar panels is a source of uncertainty in this study. In locations with a high level of solar radiation, the total adverse environmental effects over the entire life cycle can be lower due to the greater volume of produced useful products (electricity). [PERSON] and co-authors [72] apply the LCA methodology to a pilot process of recycling of crystalline-silicon (c-Si) PV panels on the Italian \"SASIL S.p.A\" company. The functional unit was 1000 kg of PV waste panels, including internal cables. The system boundaries of the LCA included \"gate-to-gate\" recycling processes, starting from the delivery of the waste to the recycling plant and ending with the sorting of the different recyclable material fractions and the disposal of residues. The transportation of PV waste to the recycling plant was considered, while the decommissioning of the PV plant was not.