There are three differences between our study and previous academic studies published. First is on the scope of analysis. In previous life cycle analyses of wind energy, the focus has mainly been on individual wind turbines with rated power outputs ranging from 100 kW to 4.5 MW rather than on entire wind power plants [2,7-9]. Only two studies surveyed have considered wind power plants, but these plants consisted only of wind turbines with relatively small rated power outputs ( 500 kW). As the wind power plant is in fact the smallest and most basic functional object and turbines of larger rated power outputs become more and more common, there is a need to update these studies. In this study, we discuss the differences in CO2 emissions between wind turbines and wind power plants. The second difference concerns methodology.