In this study, the amount of CO2 emitted per kWh of electricity generated was selected as the indicator of the environment impact of wind energy. First, raw material consumption and electricity production during the lifetime of individual wind power plants within the system boundary was collected. Then, the emission factor provided by in the IPCC Guidelines for National Greenhouse Gas Inventories was adopted to calculate CO2 emissions from different materials. Finally, the CO2 emission per kWh electricity produced was evaluated. An advantage of this calculation is the transparency of the whole calculation process and associated results. Besides the material consumption statistics from the turbine producer (Vestas in this study) and the emission factor from IPCC, other data or particular software is needed for the study.