# Cumulative Impact of Wind Farm Noise
## 5 Discussion  
Certain authors [15; 16] point out that the levels of infrasound pressure produced by wind turbines are well below the generally accepted hearing threshold of a human ear, concluding that they cannot produce negative effects on human health. However, many authors [15; 16; 17; 18] still maintain that just as there is no conclusive proof of the potentially detrimental effects of long-term exposure to the wind turbine-generated infrasound, especially in the low frequency range, there is no proof of the opposite either. Therefore, it is not possible to draw strict conclusions on the nature of the impact. One thing is certain, though: the impact of wind power plant noise must meet the legally prescribed values. In this process, special attention should be given to the impact of noise on the well-being of people inhabiting the future wind farm area by using good practice examples, on the one hand, and noise impact monitoring, on the other. The paper shows the way in which aspects of noise produced by two wind farms (cumulative impact) can be assessed as part of the partial assessment in the SEA process. Namely, the foundation for using SEA in planning the development of wind farms is choosing the proper options for minimizing or completely eliminating possible conflicts in space between a wind farm and the elements of the environment [27; 64; 65; 66; 67], in this case in regards to noise generation. In that way, the optimum solution can be reached at the start of developing the project so as to exclude the financial risks in later phases of project development, which is of special importance for investors. When preventive environmental protection is fully applied, SEA becomes the best instrument for assessing the effects of wind farms before designing and developing a particular investment. Partial noise impact assessment for the purpose of SEA is done by integrating the modeling results into the multicriteria evaluation, which is the core of the SEA process. The integration is done according to SEA criteria (Magnitude of impact, Spatial dispersion of impact, Probability of impact, and Frequency of impact), which are elaborated by [PERSON] et al. [24; 67; 68]. In this way, the decision-makers are presented with the expected effects of developing the planned projects--in this specific case, the noise effects. Based on that information, they can either accept the planned solutions or opt to introduce certain changes to the plan. In the specific case described in this paper, the noise limit values are not exceeded, although there are changes in the noise contour as compared with the contours of individual wind farms. Also, in the case of cumulative impact, certain receptors move to the higher noise level contour. If the modeling shows some receptors to be exposed to higher levels of  
Figure 4: Diagram of results of modeling cumulative effect of noise. noise, then wind turbines should be relocated to the optimum position, which is the main point of preventive planning and protection as the most desirable principle. That was the case with some other projects in the territory of the Republic of Serbia, where the modeling results pointed to noise values that exceeded the prescribed day and night limits. In such cases, different approaches to the issue are possible. Wind parks C rni Vrh and Lovcenc are interesting examples of problem solving in the case of noise increase. After the modeling results pointed to the expected rise in levels of noise above the legally prescribed limits, the Investor of the Crni Vrh Wind Farm appropriated facilities in the zone of increased noise levels and eliminated possible issues in later stages of project development. In the case of the Lovcenca Wind Farm, the Investor cancelled seven wind turbines and relocated twenty-nine turbines so as to eliminate the impact on the receptors in the impact zone. The noise impact is not the only reason behind turbine relocations, but it is the major one, having in mind the confirmed effects of noise on human well-being.