## 4 Results and Discussion
### LCA of Wind Turbines or Their Components
The primary data were collected from four representative European power plants with state-of-art technology provided by Siemens Wind Power. The functional unit was 1 kWh. The EoL of the power plants consisted of the management of construction and demolition wastes. The recycling of turbine blades and foundation was included. The recycling process for composite blades was mechanical shredding and incineration in cement production. The recycling process for the cement foundation was crushing with the positive output of crushed gravel. The results in physical units were obtained only for the impact category \"climate change\", and they indicated the preference of land-based wind parks. [PERSON] [84] studied a floating 24-MW offshore wind farm's life cycle from \"cradle-to-grave\". The multicriteria approach was used for LCIA. It is based on the combined performance of ILCD, CED, and ReCiPe 2016 MidPoint method (H). An additional parameter of \"water use\" was estimated according to the AWARE method [85]. The functional unit was 1 kWh of electricity. The recycling technology was not specified. Presumably, this is the usual recycling of metals and landfill for composite blades. The contribution of the EoL stage to all the adverse effects was quite large due to the need to use diesel-powered marine vehicles for decommissioning a wind farm located 16 km from the coast. In a report of Vestas [86], the environmental impacts associated with the production of electricity from a 50-MW onshore wind plant were studied using a cradle-to-grave LCA. The functional unit was 1 kWh of electricity. At the EoL stage, it was assumed that metals are recycled (85-87% of the total turbine mass), and composite blades are incinerated by 50% and landfilled by another 50%. Blades and foundation treatment did not bring avoided environmental impacts. An important distinguishing feature of this work is the high certainty of data on all processes. It included the process of transporting equipment to the installation site and the recycling site and the process of connecting to the grid. The estimated transportation of the turbine components ranged from 50 km for the base to 2200 km for the blades; the transportation distance to the recycling site was assumed to be 200 km. [PERSON] and [PERSON] [87] calculated the emissions of a 1.65-MW wind turbine over its entire life cycle (including EoL). The functional unit was 1 kWh of electricity. An important feature was a fact that emissions related only to energy consumption were taken into account. The initial data were obtained from literature and taken in an averaged form. EoL treatment technologies were not specified, but from the context of the paper, one can conclude that it was recycling of the metal parts of the turbine and the landfilling of the blades. Transportation distance was not specified. [PERSON] [88] performed a classic LCA for several types of turbines: medium ground-level power (1, 2, and 2.5 MW), powerful offshore in shallow water (2 and 2.5 MW), and offshore in deep waters (2.5 and 5 MW). All intermediate and final calculated data were averaged over the class of turbines. The functional unit was 1 kWh of electricity. EoL treatment involved the recycling of metal components of the turbine in the range from 55% (for aluminum) to 90% (for iron, steel, and copper) and 100% disposal of composite parts and a concrete base. Transportation of turbine components to the installation site was taken into account, and the maximum distance was assumed to be 10,000 km. Transportation to the place of recycling was not taken into account. The results of the study show that although offshore wind parks have a higher capacity factor (45-47% compared to 35% for onshore wind turbines), in most categories, they produce more significant adverse impacts. This is precisely due to the contribution of the EoL stage, in which concrete foundations are left in the ground.