## 4 Results and Discussion
### LCA of Wind Turbines or Their Components
[PERSON] and [PERSON] [57] performed a life cycle inventory and assessment of the various phases of the 2-MW Gamesa onshore wind turbine life cycle in terms of TRACI impact categories with SimaPro Software version 8.3.2. The study considered RES recycling (OLR) with 98%, 90%, and 50% recycling rates for metals, plastic, and electronic components, respectively. Fiberglass (blade material) and lubricants were considered 100% landfilled. The most notable result of the study is the conclusion regarding the environmental friendliness of transporting new turbines to the installation site: the impact of truck transport for the distance 656 km is, in most cases, comparable or even greater than that of transoceanic ship transport, which was 8325 km. The effect of transporting the used parts of the turbines to the place of recycling or landfill was not taken into account. [PERSON] [89] used GEMIS software for modeling the entire life cycle of two types of wind turbines: a 2-MW turbine with a gearbox and a 1.8-MW turbine without a gearbox. The paper assumed that the 2-MW turbine was transported for a distance of 2700 km, and the 1.8-MW turbine was transported for a distance of 1100 km by truck. The transportation distance to the place of recycling or landfill was not indicated. Only energy-related impact categories were considered. Recycling of stainless steel, cast iron, and copper was considered, whereas epoxy, plastic, and fiberglass were incinerated. The concrete foundation was 100% landfilled. Comparing the results for the two turbines, the authors concluded that the impact of the 1.8-MW turbine without gearbox was a little less. The authors of [90] compared energy demand for the entire life cycle of 2-MW onshore wind turbines with a tall (76.16 m) tower. The study compared the ecological impact of traditional steel and innovative lattice towers. A lattice tower needs around 35% less steel, and it has an almost 33% lighter foundation, which gives a significant advantage for transportation and construction. GEMIS software was used for modeling total energy demand. The transportation for 240 km by truck and 1020 km by ship to the location of installation was considered. EoL treatment included recycling of metals with 5-10% loss, the 100% incineration of epoxy, fiberglass, and plastic, and 100% landfill of the concrete foundation. The distance to the place of processing, incineration, or landfill was not indicated. The study concluded that the turbine with a lattice tower was 32% less impactful on the environment in terms of CO2 emissions. Of the studies modeling LCAs of composite materials, only a few can be distinguished. For example, in [91], recycling by pyrolysis of carbon fiber reinforced polymers (CFRPs) was investigated with an LCA according to the ReCIPe Midpoint (H) 1.10 method. The functional unit was 1 kg of CFRP waste. It was estimated that recycling can avoid \(-\)0.08 kg CO2 eq. due to the recovery of methanol and ethyl acetate. In [92], a limited version of LCA was carried out for several possible options for handling CFRP waste. Only CO2 emissions were taken into account. The models in this study were based on hypothetical CFRP treatment routes because exact facility locations were not identified. \"Gate-to-grave\" models have been developed for CFRP waste treatment by landfilling and incineration, beginning at the point of waste collection and including waste processing (disassembly, shredding), transport, and waste treatment (landfill, incineration). For recycling, a \"gate-to-gate\" approach is taken, which includes the production of composite materials from recycled carbon fibers (r-CF) and the use and/or disposal of other recyclate materials. Maintenance and facility construction is also not included in the LCI boundaries. The results demonstrated that landfilling produced minor GHG emissions (24 kg CO2 eq/t CFRP) due to the inert nature of CFRP waste; incineration resulted in the greatest net GHG emissions (2011 kg CO2 eq./t CFRP) from the combustion process.